MOULTING AND BROODING PATTERNS OF THE LITTLE SPIDERHUNTER (ARACHNOTHERA LONG/ROSTRA)

INSARAWAK.

Andrea Chin Yen Fei

(25891)

QL 458.4 Bachelor of Science with Honours CS39 (Animal Resource Science and Management) 2013 2013

ACKNOWLEDGEMENT

There's nobody else that I would want to thank more than my parents, Alice and

Anthony. Thanks for the support, time and money invested into my Bachelor study. Thanks

for the love and thrust that have been given to me throughout these three years learning

experience. It has taught me tremendously, both academically and as a person. Thanks to my

grandma in heaven that had always inculcate the love for animals in me since young. You

have been such a great role model and a great friend.

To Professor Mustafa Abdul Rahman, who is my mentor and supervisor. Thanks for

the guidance and patience into leading me on conducting the project. Thanks for gaining my

interest and inspired me into selecting aves for my project. I thank my examiner, Professor

Andrew Alek Tuen who have been advising and commenting on my project.

To Mr. Nasron Ahmad and Mr. Isa Sait, the two Department Zoology's staffs that

were ever-ready into welcoming me for field trips and guidance. Thanks for the time and

effort spent into providing help to carry out my field work. Thanks for giving me an

opportunity in building friendship and thanks for the knowledge and skills shared.

To Yakup, I would like to express my utmost gratitude and appreciation for the

mental support, encouragement, patient, guidance, love and care because these are the things

that enrich my life and lifted my spirits . .

DECLARA TION

I hereby declared that I have completed this thesis on the 'Brooding and Moulting

Patterns of the Little Spiderhunter (Arachnothera longirostra) in Sarawak on my own and

without the use of any other references and sources other than those mentioned and cited in

this thesis. This thesis is written for my Final Year Project in completing my Bachelor of

Science with Honours in 'Animal Resource Science and Management'.

This thesis has not been submitted for evaluation to any other institute, university or

institution other than Faculty Resource Science and Technology, Universiti Malaysia

Sarawak (UNlMAS). All parts of the thesis which are cited literally from publications such as

books and journals are acknowledged. I further confirm that I have submitted to my

supervisor, Professor Mustafa Abdul Rahman and examiner, Professor Andrew Alek Tuen

this thesis in both hardcopy and digital text file.

Signature: ........... ... ......................... .

vr (JA/~. ~/3.Date: ....... .0 .........if................ ...

ii

Pusat Khidmat MakJumat Akademik UNIVERSJTI MALAYSIA SARAWAK

Table of Content Title and Front Cover

Acknowledgement

Declaration

Table ofContent

List ofAbbreviations

List ofTables and Figures

Abstract

Chapter 1 General Introduction

Chapter 2 Literature Review

Chapter 3 Materials and Methods 3.1 Sampling Areas

3.2 Placement ofNets at Sites 3.3 Previous Data Record Used 3.4 Capture Technique 3.5 Bird Handling Technique 3.6 Data and Collection Analysis

Chapter 4 Results 4.1 Individual Captured

4.2 Moulting 4.3 Brooding 4.4 Body Weight

Chapter 5 Discussion

Chapter 6 Conclusions

References

Appendix

11

III

IV

v

1 - 2

3-5

6-8

9 - 10 11 - 12

12 13

14 - 16

17

18 19 - 20

21

22 - 28

29

30 - 32

33 -34

iii

List of Abbreviations

NE - North-East

SRP - Sebangkoi Recreational Park

KNP - Kubah National Park

UNIMAS - Universiti Malaysia Sarawak

, iv

I

List of Tables and Figures

Figure 1. An adult Little spiderhunter at Kampung Mata Parang, Asajaya. 4

Figure 2. Examining moulting for the 10 primary feathers of Little spiderhunter. 14

Figure 3. A brood patch with score 3, showing sign ofbare breast. 15

Figure 4. Monthly cumulative curve of individuals captured. 17

Figure 5. Numbers of individuals showing presence or absence of moulting on monthly

basis in Sarawak. 18

Figure 6. Monthly brooding patterns in relation with number of Little spiderhunter

captured. 20

Figure 7. Annual mean weight of the Little spiderhunter in Sarawak. 21

Figure 8. Monthly rainfall intensity at 11 stations in Sarawak. 25

Figure 9. Monthly rainfall pattern in Sarawak. 26

Figure 10. Climatic seasons on the North West Coast ofBorneo / Birds annual activities. 27

Table 1. Sampling locations, coordinates and dates ofdata collection for the Little

spiderhunter throughout Sarawak as recorded by Professor Mustafa Abdul

Rahman. 12

Append ix I. Map for the state ofSarawak. 33

Appendix II. Drawing showing a cloacal protuberance at its peak in a male passerine. 34

Appendix III. Drawing showing brood patches in different stages ofdevelopment. 34

Appendix IV. Wing during complete moult of an adult bird with the primary

feathers scoring from PI to PIO. 34

v

ABSTRACT

Little spiderhunter (Arachnothera longirostra) is a common Bornean bird that lives

on lowland primary and secondary forest in both undisturbed and disturbed habitat. The

annual cycle of moulting and brooding patterns by the Little spiderhunter is described.

These are used to estimate the breeding season that fits into its annual cycle. Factors such

as climatic patterns that influence their breeding season are analysed as well. The result

showed that there is a distinct pattern between the amount of rainfall in relation with the

breeding season of Little spiderhunter. The high amount of rainfall during the North-East

(NE) monsoon season of Sarawak at the end till early of the year (November-February)

flourish the plants that leads to the flowering and fruiting season during March and

October. This increased the amount of food availability for nectarivorous species such as

the Little spiderhunter. The population of frugivorous insects that feed on plant parts such

as young leaves experience a population flush when the NE monsoon is over. Little

spiderhunter that is known to be an opportunistic breeder took this conducive period as

their breeding season on an annual cycle in Sarawak. This birds breeds from May to June,

when the seasonal condition is conducive.

Key word: Little spiderhunter, breeding, mOUlting, brood patch, season

Andrea Chin Yen F ei Brooding and Moulting Patterns of the Little Spiderhunter in Sarawak Animal Resource Science and Management Faculty of Resource Science and Technology, Universiti Malaysia Sarawak (UNIMAS)

1

ABSTRAK

Engkerasak (Arachnothera longirostra) adalah spesis burung biasa Borneo yang

tinggal di hutan tanah pamah rendah dan menengah di habitat yang tidak terganggu dan

terganggu. Kitaran tahunan Engkerasak telah dikaji. Dua ciri-ciri penting iaitu corak

'brooding' dan 'moulting' untuk Engkerasak telah digunakan untuk menganggarkan

musim pembiakan yang sesuai dengan kitaran tahunannya. Faktor-faktor seperti corak

iklim yang mempengaruhi musim pembiakan turut dikaji. Hasil kajian menunjukkan

terdapat corak yang tertentu antara jumlah hujan tahunan berhubung dengan musim

pembiakan Engkerasak. Jumlah hujan yang tinggi semasa Musim Tengkujuh Timur-Laut

Sarawak pada akhir hingga awal tahun (November-Februari) menyemburkan tumbuh­

tumbuhan. Musim berbunga dan berbuah turut berlaku antara bulan March dan Oktober.

Musim ini meningkatkan jumlah makanan untuk spesis nectarivorous seperti Engkerasak.

Spesis serangga frugivorous yang memakan bahagian tumbuhan seperti daun-daun muda

akan mengalami populasi meningkat apabila musim tengkujuh Timur-Laut berakhir.

Engkerasak yang dikenali sebagai 'opportunistic breeder' ini mengambil kesempatan

sepanjang tempoh kondusif ini sebagai musim pembiakan mereka di Sarawak. Musim

pembiakan burung ini ialah dari Mei hingga Jun apabila keadaan habitat adalah kondusif

Key word: Little spiderhunter, breeding, moulting, brood patch, season

Andrea Chin Yen Fei Brooding and Moulting Patterns of the Little Spiderhunter in Sarawak Animal Resource Science and Management Faculty of Resource Science and Technology, Universiti Malaysia Sarawak (UNIMAS)

2

CHAPTER ONE

INTRODUCTION

Little spiderhunter (Arachnothera tongirostra) of the family Nectariniidae can be

found along a wide geographical range of Southern Asia from Nepal, Peninsular India to

South-West China, Indochina, Borneo, Java, central and southern Philippines (Phillipps

and Phillipps, 2011; Smythies, 1981). This species is of Least Concern for 2004, 2008 and

2009 under the IUCN Red List, 2012. The Iban in Sarawak called it Engkerasak, Engrasak

and Kerasak (Smythies, 1981). Little spiderhunter are known to be found in both disturbed

and undisturbed mixed dipterocarp forest, mangrove, lower montane forest, kerangas or

any tree plantations (Smythies, 1981)

It has an average body length of 16 cm, a bill length of 36 mm where both the sexes

morphologically look similar (Phillipps and Phillipps, 2011; Shoko et at., 1999). Their

calls are easily identified as it is always a clear Chip note; single and harsh Chip while they

are in flight and a rather prolonged and higher pitched Chip while perching or resting

(Smythies, 1981). They are known to be both a nectarivore and insertivore whereby they

occasionally may feed on insects such as black ants, spiders, stick insects and other

anthropods, especially during the breeding season (Sodhi et at., 2005; Smythies, 1981).

The Litt le spiderhunter is often seen around banana and ginger flowers in lowland primary

and secondary forest as it specialises in feeding the plant nectar (Phillipps and Phillipps,

2011).

Although Little spiderhunter is known to be feeding on spider, that is not the main

reason of how it gets its name. They appear to be hovering in front of the spider web to

rch for food and they also tend to take the cobwebs itself (Davison, 1939). Cobweb is

one of the materials that the Little spiderhunter would utilise beside dead leaves to build

3

their nest that are shaped like a pocket, settle on the underside of some large leaf (Davison,

1939; Smythies, 1981).

Spiderhunter are known to be the pollinator of Bomean gingers and bananas where

the plants have long floral tubes, larger stigmas and anthers; this species specialises in

pollinating the flowers as they are capable of inserting their bills into the short floral tubes

(Shoko et al., 1999). The ginger species pollinated by spiderhunters such as Arachnothera

longirostra and A. robusta are Amomum roseisquamosum, Etlingera afJ. Brevilabris, E.

punicea, Hornstedtia reticulate, H. leonurus, H. afJ. Monor, E. afJ. Metriocheilos and

Plagiostachys strobilifera (Shoko et al., 1999). The flowers' pollens are deposited on their

forehead or on their long bills of 36mm while feeding on the nectar (Shoko et al., 1999).

The wild banana act as a 'keystone species' as it sustains the life of Little spiderhunter,

along with other species in mixed deciduous forest such as the Streaked spiderhunter,

civet, squirrel and fruit-bats by providing food resources to these species especially during

the dry season (Dokrak et al., 2010).

Figure 1. An adult Little spiderhunter at Kampung Mata Parang, Asajaya.

4

,.... ,.. Pusat Khid t MVNlVERS1;:~ .t .a~umat Akademik

"~YSlA SARAWAK

Objectives

This study on Little spiderhunter (Arachnothera longirostra) in Sarawak has the

objectives offmding out the breeding season of the bird throughout Sarawak by describing

how moulting and brooding patterns can fit in the annual calendar of the species (Ian,

2009); and to investigate whether the brooding and mOUlting show patterns of seasonal

occurrence (Ramos, 1994).

Problem Statement

Knowledge of the moulting and brooding patterns of this speCIes is crucial in

understanding the sequence of annual events such as the breeding season, number of clutch

size, clutch volume and obtaining evidences of biparental care (Christer and Juha, 1998;

Ian, 2009; Jonsson, 2006). It also helps to understand the ecology (Ian, 2009) of the species

in its natural habitat such as food resources availability, weather and habitat conditions. No

information is available on the ecology and breeding season of most Borneo birds (Ramos,

1994; Sreedharan 1997). The result of this fmding would help ornitho logist to understand

the ecology and biology for this species that allows it to sustain its reproductive continuity

and survival in Sarawak. The evaluation of this question would provide the primary step

into understanding the ecology ofbirds in Borneo's forests (Ramos, 1994).

Hypothesis

The brooding and moulting patterns are significant features in determining the

breeding season of the Little spiderhunter whereas the alternative hypothesis was the

otherwise.

5

CHAPTER 2

LITERATURE REVIEW

Both moulting and brooding involved feathers found respectively on the wings and

abdomen of the bird. These feathers, with all the collective feathers such as the contour

feather, semiplume, down feather, powder down, bristle, filoplume and others make up the

plumage (Ginn and Melville, 1983). Plumage is the characteristic that distinguish bird from

other taxa of animals and also act as a key tool for species identification. The functions of

plumage include streamlining and insulation, feathers and flight, waterproofing and

buoyancy (waterbirds), display and camouflage, feather maintenance and abrasion (Ginn

and Melville, 1983).

By determining the patterns of mOUlting and brooding, it can help to indicate the

starting period of the breeding season for the Little spiderhunter. The moulting and

brooding strategies in most Borneo bird species, including the Little spiderhunter is not

known (Sreedharan, 1997). Thus, by studying on these two factors, it can lead to the

determination of reproduction season for the bird.

Moulting happens when feathers are generally being replaced sequentially where

each feather is shed as a new one begins to grow below (Ian, 2009). Moulting is the overall

process of replacement of the plumage (Ginn and Melville, 1983). In other words,

replacement of accidental losing of feathers is not considered as moulting (Ginn and

Melville, 1983). Moult requires a high demand of energy and it is considered one of the

major avian annual cycles (Aroyo et ai., 2004). Moulting is always linked to breeding

season where migration occurs because the timing of these cycles has to be adjusted

ectly to minimise the overlap in their energy demands (Aroyo et ai., 2004). Moult

6

would happen due to migration for flight efficiency and changing of new set of feathers for

courtship purpo es.

Moulting is a process that is highly associated with breeding season where the

males may change feather plumage or worn feathers for territorial defence or sexual

display. Evidence of both cloacal protuberance and brood patch are important

characteristics to identifY during breeding season.

Brood patch or known as incubation patch is a bare patch developed on the

abdomen of most incubating birds. Its presence or absence can help in detennining the

breeding season of the bird (Sreedharan, 1997). This incubation patch is a featherless area

on the breast (Jonsson et al., 2006). According to 'The Bird in Hand Manual', the brood

patch helps in increasing the efficiency of heat transfer from the bird's abdomen to the

eggs. Birds such as the Little spiderhunter where both the sexes are morphologically

similar (Phillipps and Phillipps, 2011), are called monomorphic sex. It is thus possible that

both the male and the female may develop brood patch. This can also help to detennine

whether both the sexes invest in biparental care where the male and female takes tum in

taking care ofthe young and eggs (Christer and Juha, 1998).

Brood patch is also important to study the clutch volume and clutch size where the

amount of heat loss through the patch is directly proportional to the clutch size (Jonsson,

2006). This finding will enable the number of clutch during a breeding season to be

determined. From a study conducted by Sreedharan at Gunung Gading National Park in

1997, he found that the male of both Yellow-rumped Flowerpecker (Prionochilus

xanthopygius) and Orange-bellied Flowerpecker (Dicaeum trigonostigma) have brood

tch; some species of male have sign of partially bare patch and most have a fully

de ped brood patch.

7

If the brood patch area appear to be bigger than the minimum area required for the

clutch size then this would show that the bird has efficient incubation whereby the female

transfer more heat to the eggs, and reduce the resettling rate. It also increases contact areas

between the brood patch and feathers which are related to the amount of rainfall, especially

for birds of the tropical region such as Little spiderhunter (Brigette et at., 1992). With over

1500mm of annual rainfall, breeding of the nectarivores and fiugivores during the dry

season may be affected by the lesser blooming of flowering plants, thus lower reduction in

anthropods numbers compared to the drought season (Brigette et at., 1992). This indication

is a crucial information into determining the breeding season of the Little spiderhunter as

they have been known to feed on small-sized anthropods during this period (Sodhi et at.,

2(05).

8

CHAPTER 3

GENERAL MATERIALS AND METHODS

3.1 Sampling Areas

Data coIlections at four sampling sites have been conducted. The locations include

Sebangkoi Recreational Park (28 October 2012 - 2 November 2012) for seven days and six

nights; Kubah National Park (30 November 2012 - 2 December 2012 and 8 - 10 March

2013) both for three days and two nights, Kota Samarahan (29 January 2013 - 22 March

2013) and Kampung Mata Parang, Asajaya (29 -31 March 2013).

The climate of Sarawak is equatorial, with the day time temperature of 28-34°C.

The average annual rainfall is between 334 - 460cm, and the average humidity is 70%

(Zainudin et al. 2012). The coordinates for Sarawak is 1°38'N for latitude, 113°35'E for

longitude (Kumar, 1972). Refer to sampling sites located throughout Sarawak at the map

provided in Appendix I.

3.1.1. Brief Description of the Sampling Locations

Sebangkoi Nature Reserves

Sebangkoi Nature Reserves is located right beside the Sebangkoi Country Resort

and is around 30km from Sarikei Town. The forest type is secondary and cultivation forest

whereby it is the local fanners' fruits orchard.

9

Kubah National Park

Kubah National Park is located in Matang Sarawak and is about 20km from the

Kuching City (Azlan et al., 2008). It is 2742 ha in size and the forest type consists of

mixed dipterocarpforest, riverine forest, montane forest and heath forest (Azlan et al.,

2008).

Kota Samarahan

The climate of Kota Samarahan and that of Kuching North City is equatorial with

day time temperature of 28°C to 34°C, 330cm and 460cm average rainfall and 70%

average humidity. Areas chosen as sampling sites are Universiti Malaysia Sarawak

(UNlMAS), Kampung Sebayor and Kampung Meranek. The forest type at UNlMAS and

Kampung Sebayor are quite similar where there are a range of development and land use

patterns changes with increasing human populations and aggressive tree planting around

residential areas and along the roads (Zainudin et aI., 2012). Kampung Meranek's orchard

is a vast area of land planted with local fruits such as pineapples, papayas, bananas and

small patches ofoil palm plantation.

Kampung Mata Parang, Asajaya

This orchard belongs to the local farmers where banana is mostly planted. The

climate is equatorial and similar to Kota Samarahan as it is located just 49km away. The

orchard settles in the middle of the residential areas, surrounded by roads and houses. The

plantations here are mostly banana.

10

3.1 Placement of Mist Nets at each Sampling Sites

Kubah National Park

During the first trip, ten mist nets were deployed along the main trail (Rayu trail) at

Kubah National Park throughout the three days, two nights sampling periods of December

2012. The mist nets were not placed at the higher elevation at any further trials due to the

short sampling days. On another trip in March 2013, ten mist nets were deployed along

BeHan trai~ and another two along Rayu trail where some banana and ginger plants are

found.

Sebangkoi Nature Reserves

Mist nets were set up near the ground-storey level where ginger and banana plants

were commonly found. The Little spiderhunter feeds on nectar of both plant species

(Phillipps and Phillipps, 2011). At Sebangkoi Recreational Park, the placing of mist nets

were as fullow: (Site A - ten mist nets), (Site B - ten mist nets), (Orchards - six mist nets)

making up a total of twenty-six mist nets by the end of the sampling days. The twenty mist

nets at Site A and B were set up throughout the seven days of sampling period, while six

mist nets at the orchard were set up for the last five days of sampling period since there are

extra mist nets available. The orchard was chosen since it has banana and ginger plants

throughout the plantation.

Kota Samarahan

During the two months sampling at Kota Samarahan, ten mist nets were set up on

every trip. The locations chosen were UNIMAS Aboretum, Zoology forest, old Zoology

furest, along the road sides of East and West Campus, Kampung Sebayor and orchard of

Kampung Meranek.

11

Kampung Mata Parang, Asajaya

Ten mist nets were set up around the orchard where Little spiderhunter would most

likely to visit, namely near the banana plantations, flowering trees of the wild ginger and

Ficus plants (Rahman, 2000).

3.3 Previous Data Record Used

Table 1. Sampling locations, coordinates and date of data collection for the Little spiderhunter throughout

Sarawak as recorded by Professor Mustafa Abdul Rahman.

Sampling Sites

Matang Wildlife Center

Samumsam Wildlife Sanctuary

Kampung Temirat, Asajaya

Gunung Gading National Park

Padawan

Kubah National Park

Lambir Hills National Park

Gunung Santubong

Sungai Asap 8elaga, Kapit

Date Coordinate

7 -12 April I 996

23-25 April 1996

8-9 May 1996

13-16 May 1996

21-23 May 1996

6-11 October 1996

28-30 May 1996

5-6 June 1996

19-21 June 1996

25-27 June 1996

24 October 1996

26 October 1996

30 Oct. - 1 Nov. 1996

10 November 1996

13-16 May 1996

6-9 June 2010

1°57'N.I09°38'E

1°33'N,110030'E

1°41'N,109°50'E

1°8'N,1l0015'E

1°36'N,1l001l'E

4°12'N, 114°01'E

1°44'N,1l0020'E

2°30'N 113°15'E

Data on the annual rainfall pattern in Sarawak by Alenjendro et al (2000) was used

analyse the breeding season of Little spiderhunter as well.

12

.4 Capture Technique

The method employed for sampling was mist-netting method. A total of ten 4­

shelves mist nets of9 or 12 m in length with a net-size of 3 (Sreedharan, 1997) were used

in capturing the species on the ground storey level of the forest where most ginger and

banana plant grows. The mist net was set at a maximum height of 3 m above ground with

the lower shelf measuring about 0.3m above ground level (Sreedharan, 2007). The mist

nets were set from 0600-1700hr when the forest birds were found to be most active (Anak

and Philip, 2002) and were checked at every two hours interval.

3.5 Bird HandUng Technique

Birds caught on mist nets were carefully removed while causing minimum or no

harm and stress to it. The removing process usually starts by disentangling the feet, then

the wings and finally the head. Then, they were carefully placed in a cloth bag and tied

with a knot to prevent escaping.

While holding the bird, two methods were applied. First was by holding the head

between the fore and middle fmger where the whole body rest in the hollow of the palm.

This method relaxes the bird and is especially used while examining the brood patch. The

other method is by holding on the tarsus using the fore and middle fmger, or the thumb and

the fOre finger. Handling of the birds from disentangling out ofthe mist nets, to measuring,

examining, ringing and photographing were done as quickly as possible to avoid the bird

from dying out from heat and stress.

13

3.6 Data Collection and Analysis

3.6.1. Data Collection

Measurement of the birds (tarsus length, bill length, bill depth, bill width, head and

bill length, wing length, tail length, wing span, total length) were done using digital

calliper (nearest O.Olmm) and ruler (O.lmm) while the weight was measured using 50 g

pesola. The date, GPS, locality, time and the basic measurements were recorded in the field

data sheet (Sreedharan, 1997). The moulting and scoring status were analysed by a

sequence of codes. The primary moult is recorded as 10 character mode where each digit

corresponds with the primary feathers by counting on the first outer primary feather that is

indicated by mode 'PI '.

Figure 2. Little spiderhunter examined at UNIMAS showed a moult scoring at primary 9 (P9) feather.

14

Brood patch stage was evaluated as follows according to British Trust for Ornithology

2009}.

o -Dry and fully feathered

1 - Dry but bare, without feathers

2 Bare breast with increased vascularization and/or mild edema

- Bare, vascularized breast with full edema

4 Bare and wrinkly breast scored a 4 which is post-full edema

{Edema is a condition which is characterized by an excess ofwatery fluid collecting in the

brood patch ofthe bird.}

Figure 3. An example of brood patch with score 3, showing sign of bare breast.

Location: Kampung Mata Parang, Asajaya

15

.6.2 Data Analysis

The weight of the bird relative to the brooding and moulting patterns were

examined as the breeding season is strongly seasonal and variations in weights could be

influence by fat, water, protein or the amount of food in the gut in preparation for the

breeding season (Ramos, 1994; Ward 1969).

The amount of annual rainfall in Sarawak was studied in relation to the moult and

brooding patterns. Since this bird's main diet consists of nectar of ginger and banana

plants, the yearly blooming for the flowers (seasonality of the flowers, fruiting and leaf

production) will be a key information to analyse the breeding season (Brigette et at., 1992;

Phillipps and Phillipps, 2011).

16

180

160

140

1 120

1 ] 100

'""0

11 80

~ 60

40

20

0

CHAPTER 4

RESULTS.

4.1 Individuals Captured

During December till February, Little spiderhunter was scarce with no or less

individuals caught compared to other times of the year. The period between May and June

bas the highest record of catch, indicating a bigger population size. Generally, the climatic

pattern has a direct impact on the distribution and abundance of food that are expected to

influence the overall seasonal rhythms of birds (Wiens, 1989) and would be used as a basis

into examination ofthe birds fluctuating occurrence (Ramos, 1994).

Figure 4. Monthly cumulative curve of individuals captured.

Annual Cumulative Curve of Little Spiderhunter Examined in Sarawak

/"/

I

//

j /

/ JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC TOTAL

17

June.

Monthly Presence or Absence of Moulting in Little Spiderhunter

~ 0---------------------------------------------------------­

~ +------------------------­

40

-I !I J

30

J . Yes

. No

20

10

oulting

Little spiderhunter seems to have a distinct moult pattern where most individuals

to stop their moult mechanism of the primaries feathers from April, reaching its peak

Moulting is an energetically costly process (Ramos, 1994) that is seems to be

iled by Little spiderhunter during the middle of the year. The moult pattern is fairly

Ie during January to March where this could be the pre-breeding season of the bird.

JS1R S. Numbers of individuals showing presence or absence of moulting on a monthly basis in Sarawak.

+­ ------------­

o ~--~~--~----

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Month

18