THESIS-FINAL PAPER

Drew University: Undergraduate student;The Department of Biology

An Observational Study at the Raptor Trust to Determine the Ecological

Status of Wild BirdsAmanda Cox

Abstract

Analysis of qualitative data from a wild bird rehabilitation center, the Raptor Trust, was

statistically analyzed and converted to quantitative data. Statistical chi square analysis was

conducted to isolate trends and construct background for future research, while determining the

validity of researchers’ and rehabbers’ hypotheses. Ultimately aiming for the advancement in

knowledge about direct and indirect human causes to wild bird endangerment and population

risk factors in the state of New Jersey.

Introduction

Classification

By 1979, it was recorded that 9,672 species of birds existed in the world9. In order to

identify these numerous and various species, Carl Linnaeus’s taxonomical classification had

been utilized at the start of the 1700’s. This type of classification considered a generalized

similarity between many species, grouping them together into their own phenotypic cluster11.

Taxonomy also considered the phylogenetic, or cladistics, classification and further grouped

species by specific characteristics in common11.

Two major types of data are utilized to classify birds into their correct taxonomical

nomenclature. “Morphological data are those that arise from measurement of characteristics of a

bird’s form or appearance”9. Since the 1980’s, behavioral data has also been included to assist

with classifying birds by phylogeny; for example, bird calls have been included in

accompaniment with nesting and breeding behaviors9. The other major type of data collection is

biochemical data, which developed closer to the 20th century9. Biochemical data considers the

DNA and chemical similarities between individuals9.

Birds have since been grouped into three major categories: Precocial birds, Altricial

birds, and Raptors. Precocial birds incubate within their eggs for a long period of time, allowing

significant time for development13. As a result of this, when the birds hatch they are able to walk

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immediately and are covered in feathers13. This category includes waterfowl birds as a majority;

such as, geese, ducks, and other webbed foot birds. They remain with their parents for long

periods of time to allow for proper social interactions, protection, and to learn proper foraging

techniques13. On the other hand, altricial birds hatch in a state of underdevelopment, requiring

their parents to physically feed and house them while providing protection and social

interactions14. Altricial birds include passerines as a majority: robins, blue jays, grackles, etc.

Raptors, also called ‘birds of prey’ significantly vary in type. ‘Birds of prey’ encompasses those

with talons and hooked bills that are predatory; for example, owls, hawks, eagles, etc. However,

these are just major categories with varying scientific classification within each.

The History

Once the hype of classification had died down, birds were considered little more than

vermin. This was particularly true for raptors because of their predatory behavior. “Some raptors

eat lambs, poultry or game birds, and they have been slaughtered in millions”8. Between 1850

and 1900 bird hunting was officially encouraged, each kill rewarded with a bounty8.

Pennsylvania permitted the scalping of owls and hawks, paying fifty cents for each scalp8. This

resulted in the slaughter of 180,000 birds in a two year period8. Market hunting emerged in the

19th century as a result of the feather trade and destroyed the pigeon, waterfowl, and shorebird

populations11. Gradually the methods of killing birds increased and diversified.

Shooting was utilized whenever birds congregated at a known nest or nesting site, as well

as when they flew within range of a gunman due to migration or foraging8. Leg traps were

extremely common and contained a spring jaw that held the bird tethered to a perch, pole,

carcasses or nest causing it to die of starvation8. In some cases, hunters would even poison birds

with pesticides deliberately, but also accidentally. Raptors often fell victim to bioaccumulation

which occurred when rodents and other prey animals were poisoned due to nuisance, the raptors

then consumed these animals and fell victim to the poison they contained11,8. Illegal live bird

trade also occurred in this time period, creating a “multi-million-dollar industry”1. Although

parrots were particularly susceptible to this industry, hawks and falcon populations also suffered

due to their desirability in falconry11.

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Vast killing focused on populations at the immediate start of the breeding season. This

particular time period was the population’s seasonal low, and eliminated the breeding adults,

causing extreme population decline8. Many species suffered elimination in the 1900’s as a result

of killing breeding pairs at the start of the breeding season8. The past 190 years has resulted in

population thinning and threats8.

Populations and Habitat Influence

After years of overexploitation, scientists decided that it was time to prevent population

depletions. They began to assess populations on a global scale, determining “the density of a

species as a measure of the number of birds in a standard area, and the geographic range as the

area over which the species occurs”11. The size of a bird often impacts the population density,

meaning larger birds tend to have lower densities because of the necessity for larger ranges to

forage11. To clarify, “overall abundance of bird species depends on the extent of its geographical

range, amount of suitable habitat within that range, and a mean density achieved within that

habitat”9.

Available habitat for particular species influences population sizes11. A habitat that is

suitable and beneficial to a species permits high rates of reproduction and overall survival of the

population11. “Sites where population is able to produce an excess of young are called sources,

and other sites, called sinks, do not support self-sustaining populations and rely on immigration

of excess birds from source populations to replace those that succumb to disease, predators, and

the like”11.

Loss of these necessary habitats cause population declines in great significance11. Habitat

depletion is a direct or indirect result of humans11. Habitats can be lost because humans convert

land for agricultural and developmental purposes; destroying native grasslands11. Wetlands are

lost as a result of water diversion to increase water availability for cities11. “More than half of the

wetlands have disappeared in the last 200 years; in California less than 10 percent remain11.

Shrub habitats are especially concerning because the natural disturbances that cause these

habitats to form no longer occur, meaning the available shrub habitats that currently exist are the

last of their kind11.

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Habitat destruction can also occur in fragments, leaving patches of unusable land. This

fragmentation reduces the likelihood of immigration among a population, reducing the chance

for an individual to move away from its birthplace for reproduction11. It also causes edges on

each habitat, an edge is where two different habitats meet, increasing the likelihood of a

predatory attack11. Since the highest density of a population remains on the interior of a habitat,

most bird egg and nestling predators remain on the edge of habitats preying on population

stragglers11. In particular, brood parasites tend to occupy open areas; thus fragmentation allows

brood parasites to occupy spaces intermittently throughout a population habitat, this gives them

more access to nests within that habitat11.

Bird Counts

As a result of constantly changing habitats and population sizes, it is important to

document bird counts periodically. This assists with determining species success, specific

species themselves, and the overall environmental success. However, studying a numerical value

for a whole population on a global scale is impossible. This causes scientists to focus population

studies on a particular area9. This defined area must consist of a large enough range that could

logically influence the estimate of the species population as a whole9. Since not all bird species

migrate at the same time or distance, it is difficult to use migration for population counts.

Thus other aspects of count are utilized; for example, counting specific concentration

areas, breeding pairs, breeding display males, etc. Due to the variety of ways to count birds, it is

necessary to know their annual cycles which are common to the majority of birds. Most birds

undergo a summer breeding season where population counts increase because reproduction rates

are higher than mortality rates11,9. Non-breeding winter season is where population counts

decrease because mortality rates are higher than reproduction rates11,9.

The desire to monitor populations caused the creation of the National Audubon Society

and the American Society for the Prevention of Cruelty to Animals11. Currently, there are “three

nationally coordinated efforts to gather data on bird populations: The Christmas Counts and

Breeding Bird Census sponsored by the National Audubon Society, and the Breeding Bird

Survey sponsored by the US Fish and Wildlife Services”15. The Christmas Count was the first

record of bird populations, originating in 1900 at Central Park in New York4. This count focuses

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on birds present in the non-breeding winter season, and remains the longest continuous record in

existence15. The Breeding Bird Census is to determine breeding pairs within a defined area and

requires repeated recordings15. This particular study enlists the help of bird watchers, and often is

not entirely accurate due to “imbalanced coverage, inadequate plot sizes, and poor record

continuation”15.

The Christmas Bird Count enlists the manpower of volunteers who follow an assigned

recording route15. Along this route of rural roads, the volunteers stop every half mile to record

the birds heard and saw in a three minute interval15. Each route occurs for about three hours

every May and June each year, to accompany each population peak and lull15.

Present Threats

Population and bird counts fluctuate throughout the year naturally, however; both are

significantly affected by existing threats that are mostly human based. As mentioned, habitat loss

and fragmentation is of great concern due to urbanization, but other threats also exist9. Pollution

from agricultural runoff, pesticides, or oil can cause significant damage to bird survivability.

Rainwater passing over streets can cause contaminants, including oil, to run into sewage which

eventually joins natural waterways11. Pesticides accumulate up the food chain by

bioaccumulation, poisoning predatory animals11. “Sewage treatment plants, livestock barns,

paper mills, mines, garbage dumps, factories, and traffic” all add to the pollution accumulating to

negatively affect birds11. There are other forms of pollution as well, but one might not consider

them to fall under this category; such as, light pollution disrupting night-migration pathways or

nocturnal birds11.

Climate change and global warming also plays a part in population changes9.

Temperature change as a result of fossil fuels, as well as, rainfall fluctuations contribute to

habitat distribution and food availability changes11. This forces species into undesirable habitats

by default and limiting reproductive success. It has already been documented that climate has

caused breeding seasons to shift in particular species, ultimately affecting migration which uses

breeding season as a signal factor11. Not only that but “the distributions of predators and disease

are also likely to change if weather patterns are altered”11. Even resources can undergo shortages

as a result of climate change9.

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Populations are also affected by naturally occurring factors. A factor to consider is inter-

specific competition where an “overlap in food and other resources provides the potential for

competition, because some of the resources removed by one species might otherwise have been

available for a second9. But competition is not limited to food resources. Thus, nests can also

undergo shortages as a result of another species overtaking them prior to the opportunity for a

second to obtain them9. Simply put, competition creates advantages for one species but

completely reduces the potential success of another; this can even cause aggressive disputes

between those individuals9.

Indirect human disturbances also prohibit natural behaviors of birds, thus negatively

affecting their survivability. Such disturbances could be vehicles utilizing back-roads, which

disturbs species nesting in isolated areas11. Overhunting still occurs in some areas and limits bird

populations9. Even netting from fishing gear or wires from telephone poles cause population

declines9.

Conservancy

George Fenwick founded the American Bird Conservancy in 1994 because “12 percent of

4,230 species in North and South America were threatened with extinction”4. Thirty-seven

percent of United States native species are currently declining in population4. The goal of the

conservancy was to collaborate the interests of many and create a uniform society that values the

protection of birds throughout the world, ultimately considering the wellbeing and effect of birds

with every use of land and environmental policy4.

This conservancy built its visionary statement knowing that birds have always been

admired, even if only by a small few. In fact, images of birds appear in “Neolithic caves,

Egyptian pyramids, Mayan temples, American homes”, and many other places4. Specific birds

have been used as symbolism for stories and life events: owls, crows, and ravens representing

death, even using storks as representation for human birth4.

Various state governments throughout the United States track wild bird populations to

determine the health of an environmental area. As stated previously, birds are extremely

sensitive to habitat changes; therefore, the health of birds in a particular area help measure the

overall health of a habitat4. Thus counting birds help measure ecosystem success, which predicts

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agricultural production, overall wildlife success, water cleanliness, and the success tourism might

bring as a result4. And of course, high tourism turnout results in increased profit for an area.

Birds also contribute to rodent and insect control, eliminating the high necessity for pesticides

that are harmful to animals and the environment4. Birds, such as hummingbirds, assist with plant

pollination and seed dispersal4.

Beyond the Conservancy’s vision statement, it has a plan of action set up to aid in its

cause. Halting extinctions to promote endangered bird population revival; targeting a network of

70 wildlife reserves aimed to protect rare species, funding support through policies, and

promoting sustainability of fisheries for seabird revival4. Conservation habitats to provide

sustainable conditions for resident and migratory birds by helping landowners manage their

properties, preserving resting sites of migration, and increasing migratory bird conservation

through funding4. Eliminating threats by addressing human-caused populations decline factors:

feral and outdoor cats, window strikes, collisions with turbines, pesticide use, and depleted

fisheries4. Finally, empowering people through communication and unification4.

Wildlife Rehabilitation and Licensing

Willowbrook Wildlife Haven founded the National Wildlife Rehabilitators Association in

1982 at the first Wildlife Rehabilitation Symposium, an event that encompassed 262 guests and

22 states7. Those attended represented various facilities working to promote wildlife

survivability: zoos, universities, and nature centers to name just a few7. The goal of the

association aimed to improve the profession of rehabilitation, develop a code of ethics and

standards, encourage unification and cooperation, and serving as a voice of respect and

professionalism7.

When a sick, injured, or orphaned wildlife animal is found, it is required by law to

immediately contact a wildlife rehabilitator or facility. Ultimately the goal of these facilities is to

release wildlife back to the wild and ensure the public’s health and safety; whether that be by

feeding babies hourly, preventing hypothermia, providing emergency stitches, or euthanasia to

prevent inhumane suffering5. However, rehabilitation facilities are required to undergo

inspection to obtain licensing. The beginning step is to obtain a rehabilitator permit, which

covers only certain species and requires only temporary holding of the animal.

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Obtaining this permit requires an apprenticeship, a letter of recommendation from that

mentor, a letter of loyalty and commitment from a willing veterinarian, an on-site inspection, and

annual reports and renewals5. Volunteers may be utilized to assist a rehabilitator at a facility, but

they must be trained with adequate knowledge5.

Funding is rarely provided by the state, unless specific studies are proposed (ie. studying

an eagle for a particular reason), and it is illegal for the rehabilitator to charge for the care of

admitted wildlife. Facilities are permitted to acquire donations, if the public citizens choose to do

so themselves5. Various general requirements must also be maintained: posting the permit,

permit renewal, maintaining a telephone and answering system, facility inspections, and accurate

record maintenance5.

Wildlife rehabilitation facilities must incorporate indoor and outdoor enclosures, strongly

encouraging enclosures that allow public viewing in some aspects, but requiring some which

prevent viewing in others5. Noise and odor levels must be limited to simulate natural wild habitat

conditions5. These facilities are also strongly encouraged to host educational programs yearly to

promote knowledge and unification for those with common goals5. And birds they release back

to the wild must meet minimum standards constructed by the state: “recognize, obtain and

process naturally found food, evade and defend against predators, acquire shelter and defend

territories, and perform normal socialization with conspecifics (though there are variations

among species)5. Any bird unable to meet these conditions must be euthanized humanely or

made a residential ambassador bird; depending on suitability determined by the individual’s

condition5.

The Raptor Trust

In 1968 Leonard J. Soucy was a naturalist, photographer, lecturer, author, and raptor

researcher that founded the Raptor Trust Avian Rehabilitation Center. However, this was not the

facility’s name originally, because the facility began in Soucy’s 14-acre backyard in Millington,

New Jersey. His 45 years of Raptor experience made him extremely capable, and the logical

option, to undertake injured raptors and nurse them back to health. It was well-known that he

kindled an intense thirst for knowledge, admirable networking skills, extensive libraries, and

strong management skills.

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This facility now encompasses a medical infirmary, an educational center, a gift shop,

and 70 exterior aviaries12. There are both indoor and outdoor aviaries, as well as, rehabilitation

and residential aviaries. By the 1970s, hundreds of birds were admitted annually at the Raptor

Trust. “From 1982 to 2015 over 90,000 hawks, owls, and other wild birds have been cared for at

the facility and nearly half have been released to the wild”12.

Currently 50 un-releasable raptors live permanently at the Raptor Trust, the majority of

which are females. These birds are kept for various reasons: inability to survive in the wild,

captive breeding, foster parenting, and public education12. It was in 1982 that the facility received

its name and became a non-profit corporation. The facility has since obtained awards and

recognition from US Fish and Wildlife Services, Us Environmental Protection Agency, NJ

Veterinary Foundation, and the Humane Society of the US12. The facility was awarded the

National Wildlife Rehabilitators Association Lifetime Achievement Award in 198612.

The mission of the Raptor Trust is to care for injured, sick, and orphaned wild birds. With

the medical facility, they are capable of doing “diagnostics, intensive care, x-rays, orthopedic

repair, and specialized diets”12. As well as educate people about wild birds, in particular about

Birds of Prey, through educational programs run by two full-time teachers and naturalists12.

These educational programs are hosted on the premises of the facility, but also are held at

schools or nature organizations12. The programs include live birds to help increase admiration

and interest, pamphlets of facts handed out, and a website with free informational resources12.

The Study

Rehabilitation facilities send annual reports to the state based on intakes and releases, but

after their submission these reports are rarely analyzed extensively. Not only that, but all birds

are initially admitted for reasons determined by the finders of the birds. These admit reasons are

rarely examined, except for the times some statistical trends are used for educational programs.

Thus these admit reasons were researched to determine commonly admitted species and

admit reasons to which they are susceptible. Analyzing the data over the past five years will lead

to an advancement in knowledge about indirect and direct human causes to wild bird

endangerment and population risk factors. As well as shifts in natural behaviors like breeding

seasons, migration patterns, or incubation periods.

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This knowledge will assist in determining preventatives that can be implemented to

revise protection plans. The hope is that this research can be incorporated into existing

educational programs and protection policies, currently in place, to further protect wild bird

populations and educate the public about the benefit of rehabilitation centers; such as the Raptor

Trust.

Methods

TRT Data Collection

Wild birds brought to The Raptor Trust are catalogued in an online database created by

one of the facility’s staff members. This database records basic information provided by the

finder of the bird. Initial questions are recorded at the time of admittance; for example: the date

of admittance, the number of birds being admitted by that finder, the state, town, and county

where the bird was found. The finder’s name, address, and phone number are also recorded. This

enables the facility to obtain further details about the initial condition a bird was found in, obtain

specific locations and spots for reintroduction after full recovery, or even to obtain records of

populations seen in a particular area for state and federal protected species. The finders also

inform the staff members of why they brought the bird to the facility by checking off a box of

common admit reasons.

Following admittance, all birds undergo an exam by a staff member. These exams

determine the bird’s species, age, and whether the bird has external parasites. Another

examination occurs after the bird has destressed in an enclosure located in the intensive care unit

or the raptor holding area. This follow up examination determines overall health of the animal,

which often includes dehydration or malnutrition, fractured bones, neurological disorders, or the

presence and degree of imprint. At this point, the admit reasons provided by the finders are

updated to reflect the true nature of the bird’s condition to provide insight as to why it required

the assistance of humans. Throughout the bird’s time at The Raptor Trust, all medical treatments

and changes are recorded in the digital database. The final outcome of the bird is the last thing to

be updated into the system, whether that means the bird was humanely euthanized, released,

transferred, or died on the premises.

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Over 11,500 data entries were obtained from the digital database and organized into an

excel file by admit date. These data entries span from April 8, 2010 to September 5, 2015.

Admit Reasons: Originals and Condensed

As previously stated, initial admit reasons are recorded by the finder of the admitted bird.

This is done by checking off a reason from a provided, staff written, list of common admit

reasons. Such admit reasons include: Caught by cat, caught by dog/other, found on side of

road/sidewalk, found on ground in yard, flew into window, hit by car, impact/other, caught in

netting/fishing line, fell from nest/orphaned, or shot. Staff members then update these admit

reasons after examinations based on injuries and the information provided by the finder,

ultimately to record a more realistic and correct reason for the bird’s presence at the Raptor

Trust.

In order to run understandable statistical tests and to ensure clarity of the research, the

admit reasons were condensed by similar categories. “Caught by cat” and “caught by dog/other”

were combined into one admit reason of “caught by animal”. “Found on side of road/sidewalk”

and “found on ground in yard” were combined to “found on ground”. “Flew into window”, “hit

by car”, and “impact/other” were combined to “impact”. “Fell from nest/orphaned”, “caught in

netting/fishing line”, and “shot” were all kept the same because they did not relate significantly

with another admit reason category.

Omitted Data

There were some admit reasons that were omitted, completely, for various reasons. For

example, despite the attempts of the Raptor Trust staff members some admit reasons are

unknown by the finder and records. This could be a result of the finder not seeing any incident

occur, delivering the bird to the facility for a friend, or any number of other reasons. As a result,

there are two admit reasons in the digital database called “Blank” and “reason not given” where

an admit reason is simply not provided. As a result, data falling into this category were omitted

because the category does not fit into a study where research focuses on admit reasons of wild

birds in rehabilitation centers.

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Some birds are admitted by the Raptor Trust staff members as a result of coming upon

injured and orphaned birds when not at the facility. Although these birds often have a particular

reason for admit, like impact, they are generally categorized as “TRT-Off site”. Due to the

uninformative nature of this particular admit reason, it has been omitted to prevent inaccuracies

in the data. The same is also true for the admit reason “Transferred”, which encompasses birds

that have been admitted from other rehabilitation centers and rescue facilities; such as the

ASPCA.

Finally, the admit reason “other” was omitted to prevent confusion and inaccuracies. This

admit reason is often checked off by the finder themselves and should be updated upon further

examination of the bird; however, this does not always happen due to immediate euthanasia,

death, or release. As a result, this admit reason is a bit misleading, indicating unknown injuries or

reason for admittance when there may truly be a more specific admit reason that explains the

bird’s condition.

Statistics

A Chi Square goodness of fit test was utilized to compare the distribution of admit

reasons overall, as well as, pairwise among all of them. For clarity the top five species, those

with the highest admit counts, were focused on for a chi square test of independence. This test

compared the distribution of the five specific species among themselves to determine the most

and least likely admit reason for each species. Another Chi Square test was utilized to determine

if population sizes in the state of New Jersey contributed to the intake counts of particular

species. All Chi Square tests were processed by the Drew University SPSS statistical program,

and all testing was overseen by a Drew University Statistics professor.

Population Data

Species population data was collected through the Audubon Society’s Christmas bird

count. All population data was tabulated and organized in a marked line graph by the Audubon

Society’s website. The population data obtained were constricted to the five-year period of

interest (2010-2015).

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Comparison Data

To determine if the statistical analyses and trends determined from the data collected

from The Raptor Trust were specific to that facility, data were also collected from other wild bird

rehabilitation center in New Jersey. By using data that was analyzed by the same statistical tests

as the Raptor Trust data, it can be determined if the admit reason trends are specific to this

particular facility or common throughout the many wild bird rehabilitation centers located in the

state of New Jersey. All data from other facilities were emailed by the facility directors or other

staff members with permission to be utilized in this research study.

Results

Admittance vs. PopulationA chi square goodness of fit test confirmed that the thirteen species of interest were not

admitted in equal numbers to the Raptor Trust facility. The same was true for all admit reasons;

the chi square goodness of fit test confirmed that admit reasons were not equal in number to each

bird admit at the Raptor Trust facility (they were not uniform). Utilizing a chi square test of

independence, it was found that all data were statistically significant. Birds were admitted to the

Raptor Trust in different proportions than expected based on their NJ populations. Admit reasons

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varied in likelihood for each species of interest at the Raptor Trust.

Figure 1: The 5 most admitted species to TRT based on admit counts were admitted in different proportions than their state population totals between 2010-2015 (A). The 5 most admitted raptor species to TRT based on admit counts were admitted in different proportions than their state population totals (B). TRT has species admitted that are considered threatened, endangered, or a special concern as determined by NJ US Fish and Wildlife Services; these species were admitted in different proportions than their state population totals (C).

According to the chi square test of independence, all thirteen species of interest at the

Raptor Trust are admitted in proportions different than their NJ populations (N= 1,050,445,

df=12) = 37,653.84, p < 0.0005. It can be seen that the five most admitted species, highest admit

count, entered the Raptor Trust in counts different than expected based on their NJ populations

(Figure 1A-C). For example, based on NJ populations, the Common Grackle was expected to

have 2,872 individuals enter the facility (as determined by the chi square test of independence).

However, only 629 individuals were actually observed at the facility (Figure 1A). In contrast,

the Mourning Dove was expected to have 341 individuals based on NJ populations; however, the

Raptor Trust admitted 1,068 individuals (Figure 1A). The Red-Tailed Hawk was also admitted in

higher numbers than expected based on the NJ populations (Figure 1A).

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The five most admitted raptor species, highest admit counts, at the Raptor Trust all had

higher admit counts then expected based on their NJ populations (Figure 1B). It can be seen that

Red-Tailed Hawks were the most admitted species of the five species focused on specifically

(Figure 1B). Based on population data, Red-Tailed Hawks were expected to be admitted most

often with an admit count of 47 individuals, but were actually admitted with 633 individuals

(Figure 1B).

Furthermore, the Raptor Trust has admitted five species that are classified as threatened,

endangered, or of special concern by the US Fish and Wildlife Services. Of these five special

interest species, all are admitted to the facility in higher counts than expected by their

populations (Figure 1C). For example, the American Kestrel was expected to have 4 individuals

admitted to the Raptor Trust, but 175 individuals were actually observed at the facility (Figure

1C). The Peregrine Falcon was expected to have 2 individuals admitted, but 63 individuals were

admitted in actuality (Figure 1C).

Admittance vs. Proximity

Figure 2: National Audubon Society has many Christmas Bird Count routes throughout the world (A). NJ has a total of 8 licensed rehabilitation centers that take in wild birds (B).

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TRT receives admit birds in counties around NJ, but the majority tend to come from counties near the facility that lack other rehabilitation centers (C).

It can be seen that the National Audubon Society has recorded an extremely large number

of Christmas Bird Count routes to account for vast numbers of bird populations (Figure 2A).

New Jersey has a total of eight rehabilitation centers that accept wild birds (Figure 2A). The

Raptor Trust, specifically a wild bird rehabilitation center, is located in Morris County. It can be

seen that the thirteen species of interest are admitted in counties relatively close to the Raptor

Trust (Figure 2C). Furthermore, it can be seen that birds from counties with other rehabilitation

centers get admitted in far less numbers; thus, proximity plays a role in admittance (Figure 2C).

Species Entering TRT for Various Admit Reasons

Figure 3: Admit totals of the top 5 most admitted birds to TRT by count. Mourning Doves admitted to TRT enter in different proportions than expected for each admit reason (A). Mallard Ducks admitted to TRT enter in different proportions than expected for each admit reason (B). Common Grackles admitted to TRT enter in different proportions than expected for each admit reason (C). American Robins admitted to TRT enter in different proportions than expected for each admit reason (D). Red-Tailed Hawks admitted to TRT enter in different proportions than expected for each admit reason (E).

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According to the chi square test of independence, all thirteen species of interest at the

Raptor Trust are admitted for various reasons (N= 4946, df=60) = 1,678.89, p < 0.0005. Thus, it

can be seen that each of the five most admitted species at the Raptor Trust were likely to be

admitted for certain admit reasons over others (Figure 3A-E). The Mourning Dove was more

likely to be admitted to the Raptor Trust because they were found on the ground (39.08%), and

least likely to be admitted due to a shooting injury (0%) (Figure 3A). The Mallard Duck was

more likely to be admitted to the Raptor Trust as a result of falling from their nest (80.88%), and

least likely to be admitted due to a shooting injury (0%) (Figure 3B). The Common Grackle was

more likely to be admitted to the Raptor Trust because they fell from their nest (56.3%), and

least likely to be admitted to the facility due to being caught in netting/fishing line (0%) or a

shooting injury (0%) (Figure 3C). The American Robin was admitted to the facility more often

due to falling from their nest (62.45%), and was less likely to be admitted due to a shooting

injury (0.06%) (Figure 3D). Red-Tailed Hawks were more likely to be admitted to the facility

because they were found on the ground (66.19%), and least likely to be admitted because they

were caught in netting/fishing line (0.21%) (Figure 3E). In all cases, the most likely admit reason

(between 2010-2015) for the top five species of interest was falling from their nest or being

found on the ground (Figure 3A-E).

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Figure 4: Admit totals of the top 5 most admitted raptor species to TRT by count. American Kestrels admitted to TRT enter in different proportions than expected for each admit reason (A). Cooper’s Hawks admitted to TRT enter in different proportions than expected for each admit reason (B). Eastern Screech Owls admitted to TRT enter in different proportions than expected for each admit reason (C). Great Horned Owls admitted to TRT enter in different proportions than expected for each admit reason (D). Red-Tailed Hawks admitted to TRT enter in different proportions than expected for each admit reason (E).

It can be seen that each of the five raptor species of interest were likely to be admitted for

certain admit reasons over others (Figure 4A-E). The American Kestrel was more likely to be

admitted to the Raptor Trust because they fell from their nest (65.75%), and least likely to be

admitted due to being caught in netting/fishing line (0%) or a shooting injury (0%) (Figure 4A).

The Cooper’s Hawk was more likely to be admitted to the Raptor Trust as a result of being found

on the ground (59.62%), and least likely to be admitted due to being caught in netting/fishing

line (0%) (Figure 4B). The Eastern Screech Owl was more likely to be admitted to the Raptor

Trust because they were found on the ground (44.8%), and least likely to be admitted to the

facility due to a shooting injury (0%) (Figure 4C). The Great Horned Owl was admitted to the

facility more often due to being found on the ground (55.84%), and were less likely to be

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admitted due to a shooting injury (0%) (Figure 4D). Red-Tailed Hawks were more likely to be

admitted to the facility because they were found on the ground (66.19%), and least likely to be

admitted because they were caught in netting/fishing line (0.21%) (Figure 4E). In all cases, the

most likely admit reason for the top five raptor species of interest was falling from their nest or

being found on the ground (Figure 4A-E).

Figure 5: Admit totals of Threatened, Endangered, and Special Concern birds to TRT. American Kestrels admitted to TRT enter in different proportions than expected for each admit reason (A). Barred Owls admitted to TRT enter in different proportions than expected for each admit reason (B). Bald Eagles admitted to TRT enter in different proportions than expected for each admit reason (C). Peregrine Falcons admitted to TRT enter in different proportions than expected for each admit reason (D). Red-Shouldered Hawks admitted to TRT enter in different proportions than expected for each admit reason (E).

It can be seen that each of the threatened, endangered, or special concern species at the

Raptor Trust were likely to be admitted for certain admit reasons over others (Figure 5A-E). The

American Kestrel was more likely to be admitted to the Raptor Trust because they fell from their

nest (65.75%), and least likely to be admitted due to being caught in netting/fishing line (0%) or

a shooting injury (0%) (Figure 5A). The Barred Owl was more likely to be admitted to the

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Raptor Trust as a result of being found on the ground (72.22%), and least likely to be admitted

for any other admit reason (Figure 5B). The Bald Eagle was more likely to be admitted to the

Raptor Trust because they were found on the ground (61.54%), and least likely to be admitted to

the facility due to being caught by an animal (0%) or being caught in netting/fishing line (0%)

(Figure 5C). The Peregrine Falcon was admitted to the facility more often due to being found on

the ground (51.43%), and were less likely to be admitted for any other admit reason (Figure 5D).

The Red-Shouldered Hawk was more likely to be admitted to the facility because they were

found on the ground (60.0%), and least likely to be admitted because they were caught in

netting/fishing line (0%) (Figure 5E). In all cases, the most likely admit reason for the top five

species of interest was falling from their nest or being found on the ground (Figure 5A-E).

Analysis of Admit Reasons

Figure 6: Over a 5-year period Admit Reason totals vary in count (A). In 2010, most birds admitted to TRT enter because they were Found on the Ground (B). In 2015, most birds admitted to TRT enter because they Fell from their Nest or were Found on the Ground (C).

Over a 5-year period (2010-2015), all admit reasons have increased in total counts

(Figure 6A). Both fallen from nest and found on ground are admit reasons that increased the

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most (Figure 6A). It can be seen that in 2010, the majority of birds admitted to the Raptor Trust

entered because they were found on the ground (Figure 6B). In 2015, fewer birds were admitted

to the Raptor Trust due to being found on the ground, but an extremely high number were

admitted to the facility because they fell from their nest (Figure 6C). Overall, admit reasons at

the Raptor Trust increased in admit counts by 2015 (Figure 1A, C).

Similarities between Rehabilitation Centers within New Jersey

Figure 7: The Avian Wildlife Center admits birds for similar Admit Reasons to TRT. In Sussex County, at the Avian Wildlife Center, the majority of its birds were admitted due to Impact Injuries in 2014 (A). In Morris County, at TRT, the majority of its birds were admitted due to falling from their nest (B).

It can be seen that the Avian Wildlife Center in Sussex County admits birds to the facility

for similar reason to the Raptor Trust. Of these admitted birds, the majority were admitted due to

impact in 2014 (Figure 8A). Morris County’s Raptor Trust admitted more birds over all in a 1-

year period; for example, TRT admitted 489 American Robins in 2014 but the Avian Wildlife

Center admitted 45 American Robins in the same year. The Raptor Trust admitted the majority

of its birds because they fell from their nest in 2014 (Figure 8B). However, both facilities

admitted the thirteen species of interest; all were admitted for similar reasons despite the two

facilities being in different counties (Figure 8A, B).

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Raptor Trust Success

Figure 8: Over a 5-year period most birds admitted to TRT enter because they Fell from their Nest or because they were Found on the Ground (A). Following their recovery at TRT, the majority of birds are released back to the wild to live a healthy life (B).

To reiterate, the admit reasons found on ground and fell from nest had the two highest

admit counts at the Raptor Trust (Figure 7A). The least likely admit reason at the Raptor Trust

was caught in netting/fishing line in the 5-year period (Figure 7A). It can be seen that the Raptor

Trust records all final dispositions for individual birds admitted to the facility. Of the thirteen

species admitted to the Raptor Trust, the majority are released back to the wild after

rehabilitation (Figure 7B). Very few individuals of the species of interest are kept as residential

ambassador birds (Figure 7B).

Discussion Qualitative data from the Raptor Trust, an avian wildlife rehabilitation center, was

statistically analyzed for trend observation. Manipulating the data into quantitative information

was useful to provide validity to impressions provided by local rehabilitators and

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conservationists. Speculated reasoning for rehabilitation necessity was supported by the data in

various ways.

Admittance vs. PopulationFive years of data from the Raptor Trust was initially analyzed to determine if some

species were admitted to the facility in higher numbers simply because that particular species has

a higher population in New Jersey. However, statistical analysis confirmed that population

densities throughout New Jersey do not impact the rate of admits at the Raptor Trust; instead,

each species is admitted in different proportions than would be expected based on their

populations.

Furthermore, when considering the five most admitted species to the facility, it is noted

that Common Grackles should be admitted in much larger quantities based on their population in

the state (Figure 1). Thus, it can be stated that Common Grackles are able to protect themselves

against potential threats that would result in their admittance to rehabilitation centers; more so

than any other species analyzed. One might believe that habitat behavior would attribute to

increased safety, or at least limited exposure to human interference, but Common Grackles are

present in various habitat types. These birds can be found in parks, residential areas, meadows,

or even agricultural fields; to name a few4. It is possible that the flocking behavior of the

Common Grackle provides increased protection per individual, especially since these flocks are

known to be extremely vocal4. After all, there has been evidence of passerine species, considered

cooperative breeders, that defend territory and young in flocks by offensive attacks against

predators11,4.

The success of Common Grackles raises the question of whether self-sustainability is a

common trend among other passerine birds admitted to the Raptor trust. However, it is noted that

the American Robin is admitted in close relation to the expectation created by population

densities in New Jersey. Surprisingly, American Robins are extremely similar to Common

Grackles: encompassing the same habitats, foraging the ground, nesting in trees, and maintaining

year round residence in New Jersey4. Perhaps Robins enter the facility in higher number because

they are simply more appealing to human finders (Common Grackles resemble Blackbirds and

Crows); however, survey and observational studies are necessary to confirm this hypothesis.

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In contrast, Mourning Doves are admitted to the facility in extremely high quantities,

much more than population density suggests (Figure 1). Thus, it can be concluded that Mourning

Doves are more susceptible to potential threats. This could be a result of habitat preference,

because these birds are often found in open areas lacking foliage4. Thus, it is important to

analyze where each species was found in terms of the facility, as well as, why each species of

interest was admitted to the Raptor Trust. Further analysis to determine which admit reasons the

species were more susceptible to in New Jersey was important for all raptor species analyzed.

This is because all five of the most admitted raptor species to the facility, including those

categorized as “threatened, endangered, and special concern” by the US Fish and Wildlife

Services, enter in extremely high amounts relative to their population densities (Figure 1).

Admittance vs. Proximity Upon analysis of proximity, it is apparent that a higher density of admitted birds occurs in

counties closer to the Raptor Trust’s location in Morris County (Figure 2). Furthermore, fewer

admits are observed in counties encompassing their own wild bird rehabilitation center. This in

itself is reasoning enough for why counties closer to Morris County result in higher admit

numbers. However, further research should be invested in comparing the admit densities per

county with the residential density of each county. It is hypothesized that there is a correlation

between county development and the amount of individual birds found in the area; a testament to

habitat loss and fragmentation.

Species Entering TRT for Various Admit ReasonsStatistical analysis of admitted counts indicated each of the five most admitted species

are categorized as “fallen from their nest” or “found on ground”. Since the categorization of the

birds at initial admit are based on the knowledge of the finder, they are not always one hundred

percent accurate. In cases of “impact” or “caught by animal”, the staff members of the facility

have the ability to adjust the admit reason to reflect a more accurate portrayal of an individual

case. However, in the case of “fallen from nest” or “fallen on ground”, it can be a bit more

difficult to determine accuracy: the bird’s age should be considered and medical assessments

utilized to determine potential pathogens or injuries, both of which can be difficult and

subjective.

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In the case of the five most admitted birds to the Raptor Trust, “found on ground” is the

most likely admit reason for Mourning Doves and Red-tailed Hawks (Figure 3). As mentioned

previously, Mourning Doves are extremely susceptible to potential threats causing high admit

numbers of this species; thus, it can be rationalized that Mourning Doves are most susceptible to

being found on the ground. This could be a result of their habitat preference, because they are

known to prefer scarce or barren lands (ie. Deserts or open grounds)4. In fact, this species is

known for scavenging the ground for extended periods of time before retreating to a higher

altitude11. Furthermore, Mourning Doves have little bias when it comes to nest construction; in

fact, they are willing to nest in dense foliage or even on the ground in the presence of humans7.

This could account for the high volume of individuals of this species entering rehabilitation

because they were found on the ground. To clarify, it is possible that humans simply misinterpret

the condition of the mourning doves, admitting healthy or normal behaving birds out of concern

for their location; such as the ground, which is actually normal with this species. Although, it is

possible that some individual birds found on the ground have fallen from their nest but were

incorrectly categorized upon admittance (ie. Fledglings). This is rational because Mourning

Doves tend to weave nests with weak materials (ie. Pine needles) lacking liners, potentially

contributing to fallen or lost young4.

“Fallen from nest” is the most likely admit reason for Mallard Ducks, Common Grackles,

and American Robins (Figure 3). It is possible that Mallard Ducks are admitted because of their

common interactions with humans, especially during migration where food resources become

scarce4. However, it is more likely that young Mallards are admitted because they have wandered

from their nests or lost their parents. This species commonly nests in depressions made in the

soil close to water, although the female attempts to conceal the nest with vegetation, it is possible

humans will still come across the young4. Female Mallard ducks are the sole incubators of the

eggs because the males tend to stray from their monogamy to partake in “extra-pair copulations”,

where many males mate with one female11,4. Despite an attentive parent, young Mallard Ducks

can be abandoned if there is a disturbance during various stages of brooding; whether it be

predators, conspecific individuals, or human visitation/disturbance11. Abandonment and loss of

young is more likely to occur in waterfowl, such as the Mallard Duck, since typically only one

parent provides the care. Single parent care is typical for waterfowl because the young hatch in a

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“precocial” state, thus they are more developed and require less care (ie. they feed themselves

and walk immediately)11. Sadly, the females are often completely abandoned by males during

incubation (unless there is opportunity for re-mating) and females can be killed off by predators

or external fluctuations (ie. drastic habitat changes); inevitably the young are abandoned and

many die without human intervention11,4. Human intervention is also common in cases where the

young inadequately feed themselves, a survival skill not performed by parents in this species;

without human intervention, the young would become malnourished and die11.

In passerines, like the American Robin and the Common Grackle, the “fell from nest”

susceptibility is shocking! American Robins enter the facility more often than Common

Grackles, but both are most likely to be admitted because they fell from their nest. Both species

tend to congregate during nesting and fledging. In fact, American Robins would be expected to

have the least amount of young admits because both parents cooperatively care for the young;

the mother care for the young at the nest, while the males care for the young independent enough

to leave the nest (ie. Fledglings and older)4. In contrast, the Common Grackles commonly group

with large numbers of similar species in the winter season but it is more common to see smaller

groupings during nesting season4. Passerine birds hatch in a state of “altricial” development,

where the young are naked and blind, thus they require intensive parental care. As a result, one

would hypothesize the American Robin, with co-parenting techniques, would result in lower

admittance of young; however, this is not the case. Perhaps this can be rationalized as a result of

nesting location: American Robins nest primarily in the mid-levels of trees but can be found to

nest on the ground or on human made structures (ie. Gutters or Garden fixtures), whereas

Common Grackles primarily nest in the high-levels of trees away from human made structures4.

As a result, it is possible that human intervention of the American Robin occurs more often

because they are in locations near human residential areas. Future observational studies are

necessary to compare nest-building and brooding behaviors of the Common Grackle and

American Robin.

Finally, through observation at the Raptor Trust, there is evidence that the public lacks

education in Passerine developmental stages of life; this results in a misunderstanding of a

healthy young bird (cared for by parents above in the treetops) versus an abandoned

malnourished counterpart. For example, American Robin fledglings (a developmental phase

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where young begin to gain independence) venture out of the nest for increasing increments and

distances each day attempting to forage on their own, while their parents keep a watchful but

distant eye from the treetops. Thus, human intervention occurs unnecessarily.

The five most admitted raptor species to the Raptor Trust are most likely to be admitted

because they were “found on the ground”, with the exception of the American Kestrel; which is

most likely to be admitted to the facility because they “fell from their nest” (Figure 4). Most owl

and hawk species have some sort of monogamous relationship with a variation of co-parenting;

this is particularly true for the raptor species of interest in this study. Female Hawks are

responsible for the feeding of young, while males hunt for food resources, bringing them back to

the nest1. Young Hawks tend to venture out of the nest, remaining in the immediate area, about

one month after hatching11. Although parents continue to feed their young, as young become

more independent, the female ventures away from the nest to assist the male with hunting11,4.

Until the young can make their own kills, the parents attentively care for their young; it is

common for human intervention to occur during the fledgling stage because the young appear

vulnerable and abandoned (due to parents being gone for increasingly longer intervals).

Similarly, Owls tend to form monogamous pair bonds that can last until the death of an

individual11,4! Like hawks, female owls perform incubation while the male provides food to the

nest; when the chicks get larger and increasingly demanding, the female leaves the nest to assist

with hunting11,4. Despite the occasional venture for food, hawks and owls are attentive parents

that care for their young up until sustainable flight is possible; thus, it is reasonable that these

types of birds are less susceptible to falling from their nest.

Much like owls and hawks, falcon species (ie. American Kestrels) have attentive co-

parenting monogamous pair bonds coming together during breeding seasons after solitary

lifestyles11,4,10. However, American Kestrels are susceptible to predation due to their continuous

vocalizations around nesting sites, and abandonment is possible if disturbance is incessant11,10.

Thus it can be rationalized that falling from their nest is a concern for young American Kestrels

who lose their parents to abandonment or predation. In addition, fledgling Kestrels tend to leave

the nest after only weeks of hatching to learn to hunt and become independent11. Furthermore,

nesting behavior of the American Kestrel potentially increases the susceptibility towards falling

from their nest. Unlike the hawk and owl species discussed in this study (Cooper’s Hawk, Red-

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tailed Hawk, and Great Horned Owl), American Kestrels and Eastern Screech Owls are cavity-

nesters; requiring hollowed out tree holes or nest boxes for breeding11,4,10. Despite this, Eastern

Screech Owls prefer denser foliage, an attribution to why they are less susceptible to falling from

their nest; whereas, American Kestrels are extremely attracted toward human made fixtures and

structures. In fact, many Kestrels have been seen hiding food or nesting on signs, fences, or even

buildings4. This occurs because of the lost habitat and nest cavities due to human encroachment

by urbanization and agricultural expansion4,15. As a result, it is hypothesized that American

Kestrels are more susceptible to falling from their nest because they have been forced to shift

their nesting sites to more densely populated human locations and structures; however, more

research in Kestrel specific behavior compared to other falcon and raptor species is necessary.

The Raptor trust admits five species considered “threatened”, “endangered”, or “special

concern”: American Kestrel, Barred Owl, Bald Eagle, Peregrine Falcon, and the Red-Shouldered

Hawk. The American Kestrel and Barred Owl species are termed threatened; the Bald Eagle,

Peregrine Falcon, and Red-Shouldered Hawk are termed endangered by the US Fish and Wildlife

Services5. Threatened species are those with the potential to become endangered if current

conditions persist; endangered species are those suffering survivability danger due to various

environmental and human threats5. Special concern species, Red-shouldered Hawk and Peregrine

Falcon, are categorized as such because they suffer survivability danger due to environmental

factors; such as, habitat loss or change and resource limitation5. All species of New Jersey state

concern are admitted more often because they were found on the ground, with the exception of

American Kestrels that are more susceptible to falling from their nest (Figure 5). It is

hypothesized that these birds are found on the ground more often as a result of habitat preference

or habitat change forced by human encroachment. In many cases, this is supported by nesting

behaviors; for example, the Red-shouldered Hawks and Barred Owls return to the same nest each

breeding season. Habitat changes and encroachments can alter breeding lands or destroy nests,

thus these species face decreasing brooding success and population declines11,4,10. Bald Eagles

and Peregrine Falcons tend to nest on cliff sides, but travel the world in younger years; therefore,

habitat shifts can disorientate these species and make them susceptible to population declines4,10.

These habitat changes and threats are potential causes that make these species susceptible to

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being found on the ground; in addition, the young of these species tend to venture out of the

nests at younger ages or wander various territories11,4,10.

Analysis of Admit Reasons and Similarities to Other FacilitiesThe Raptor trust has remained constant with overall admit likelihood in the past five

years (Figure 6). “Fell from nest” and “found on ground” have consistently remained the most

likely admit reason for all species analyzed at the Raptor Trust in a five-year period. There are

many reasons why this is the case, as was explained on a species specific level, but overall

threats have been consistent throughout the five years of analysis: habitat loss, climate change,

resource limitation, pollution and human interference11,9.

Habitat loss is an increasing problem as urbanization and development has increased.

Habitat changes cause alterations in bird population distributions and population success11,9.

Changes to habitats cause breeding declines because species are forced to choose unfavorable

nesting locations or materials. Young birds in various developmental stages face hardships they

are not evolutionarily suited to overcome when habitat loss occurs; for example, increased

predation or lack of foliage for concealment. Habitat change also alters migration patterns, which

indirectly impacts population success and breeding success11,15,3,2,6. Many researchers have

confirmed that migration, reliant on orientation and navigation during flight, is accomplished by

environmental factors11. In fact, it has been debated whether or not birds utilize odor cues or

landmarks to ensure correct navigation to seasonal stopover locations; thus, as habitats change,

various species of birds can become dioriented11. This disorientation can cause inappropriate stop

overs, ultimately affecting population success (specifically due to resource limitations/scarcity

and climate issues).

Climate change can affect more than population success during migration. It also

influences resources available in certain habitat locations; for example, rainfall alterations can

determine plant success and indirectly affect nesting for birds utilizing foliage for protection

against predation11. Perhaps more well-known are the affects temperature change has on hatching

behavior of various bird species; such as the proven correlation of higher temperatures triggering

egg laying and hatching earlier than optimally favorable3. According to Moller et. Al, 79% of

bird species show a significant negative relationship between egg laying dates and air

temperature3. It was also confirmed that migration distance, direction, timing and speed are

Cox-29


altered in a significantly negative manner with temperature changes3. As a result, weather

changes can affect population distributions and densities; proving survivability success is

dependent on favorable weather tempeartures3.

However, the largest influence on bird populations and success rates of species, is that of

human interference and disturbance. Human presence is noted to affect migration patterns and

success; for example, artificial light created by urbanization can trigger inappropriate orientation

cues and cause migration issues11. Habitat loss is also associated with human presence, being lost

as a result of urbanization and residential encroachment11. As an example, natural habitats have

been lost to human development for agricultural land, residential development, or resource

attainment (ie. Mining)11. Even human visitation (ie. Bird watchers or trail hikers) can negatively

impact bird populations; such as, parent abandonment as a result of nest disturbance11.

Furthermore, urbanization has produced toxins poisonous to various species. Fertilizers and

sedimentation causes polluted runoff water into avian drinking reservoirs and habitat locations;

specifically affecting waterfowl11.

In clarification, the present threats existing today directly and indirectly affect bird

populations and success rates. These effects cause various individuals to be brought to

rehabilitation centers. Furthermore, each of the present threats provides rational for why birds

may be found on the ground or falling from their nests! An example would be habitat loss

pushing birds to display behavioral displacement, or behaviors unaccustomed to a species (ie.

nesting on the ground versus a more favorable location; like Mallards in agricultural fields when

wetlands are not readily available). Or, perhaps, individuals suffering pesticide toxicity due to

rainwater runoff resting on the ground because they are too weak to fly away. Each threat can

rationalize and provide an example of why “found on ground” and “fallen from nest” are the two

most likely reasons an individual bird species might enter a rehabilitation center! This is further

supported by the similar data obtained by the Avian Wildlife Center, located in a different county

than the Raptor Trust (Figure 7). The same types of admit reasons can be seen at this facility;

however, further research is necessary to determine rationality for the extremely high impact

admits at the Avian Wildlife Center. Perhaps additional research focusing solely on urbanization,

specifically, developmental densities would be beneficial on a county wide basis.

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Raptor Trust Success The sheer number of admitted birds to the raptor trust in the past five years is evidence

enough for the necessity of a wild bird rehabilitation center! These admits have been categorized

based on admit reason and rationalized with issues presently threatening wild bird populations,

providing strong evidence that wild bird populations need human intervention to counteract the

negative impact humans have inadvertently caused throughout our existence. Evidence has been

provided to prove that the threats causing species to require human intervention are not occurring

solely in one county, but rather occurring on a state wide level; proven by comparing another

facility’s admitted birds.

Furthermore, it can be seen that this particular rehabilitation center (The Raptor Trust) is

successful in its endeavors (Figure 8); in fact, the majority of admitted birds are released after

examination and treatment at the facility. This analysis has also determined that birds in New

Jersey are particularly susceptible to falling from their nests and requiring human intervention

due to being found on the ground; both were confirmed by various threats presented by other

researchers.

However, it is extremely evident that all facilities should increase their educational

outreach. This is because many of the direct and indirect negative effects on wild bird

populations are a result of human presence and development; increasing education about natural

bird behaviors, nesting, and developmental stages will limit the admittance of birds in healthy

condition (ie. Fledglings). Furthermore, education will provide understanding of our impact on

natural wild bird populations; ultimately allowing preventatives to be presented and

implemented. Of course, future research of various types would be extremely useful to the

populations of New Jersey; a few have been presented within the text of this study, but the

possibilities are infinite.

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1994. P. 29-30

2. Bildstein KL. Migrating Raptors of the World: Their Ecology and Conservation. Ithaca

(NY); 2006. P. 89-173.

3. Caswell H. Birds and Climate Change. Vol. 35. San Diego (CA); 2004. P. 23-193.

4. Cooke WF. American bird conservancy [Internet]. Plains (VA): American bird

conservancy; 2013 [cited 2015 Jun 10]. Available from http://www.abcbirds.org

5. Department of Environmental Protection. NJ licensed wildlife rehabilitator information

[Internet]. Trenton (NJ): Division of fish and wildlife; 1996 [cited 2015 Jun 10].

Available from http://www.njfishandwildlife.com/rehab_info.htm

6. Ligon DL. The Evolution of Avian Breeding Systems. Oxford (NY); 1999. P. 139-328.

7. Miller EA. Quick reference: national wildlife rehabilitators association. Third Edition. St.

Cloud (MN); 2006. p. 73-85 115 136.

8. Newton I. Population Ecology of Raptors. Vermillion (SD); 1979. p. 213-215, 224-227.

9. Newton I and Brockie K. Popoulation Limitation. San Diego (CA); 1998. p. 2-6, 9-13

10. Scouten T. Wildscreen Arkive [Internet]. Washington (DC): Wildscreen USA; 2003

[cited 2016 May 1]. Available from http://www.arkive.org

11. Sibley DA. National Audubon Society: The Sibley Guide to Bird Life and Behavior. A

Chantiecleer Press Edition. New York (NY); 2001. p. 44-48, 105-109, 113-118, 213-215,

224-227.

12. Soucy LJ. The raptor trust [Internet]. Millington (NJ): The raptor trust; 2013 [cited 2015

Jun 10]. Available from http://theraptortrust.org

13. Stern S. Summer internship binder. Millington (NJ): The raptor trust; 2015.

14. Stern S. Volunteer training manual. Millington (NJ): The raptor trust; 2015.

15. Terborgh J. Where Have All the Birds Gone? Princeton (NJ); 1989. p. 11-17.

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http://www.njfishandwildlife.com/rehab_info.htm

http://www.abcbirds.org/

Documents

THESIS-FINAL PAPER