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Oksana Lane1, Oscar Brenes2, Peter Doherty3 , Pablo Elizondo4, and Robert Taylor5, Bruce Rinker1*1 Biodiversity Research Institute, Gorham, Maine, USA; 2 Reserva Playa Tortuga, Ojochal, Costa Rica; 3 Virginia, USA; 4 INBioparque, San Jose, Costa Rica; 5 Trace Element Research Laboratory,

Texas A&M, College Station, Texas, USA

*Presenter

Heavy metals screening in feathers of resident birds and neotropical migrants at

selected sites in Costa Rica and Panama

Metales pesados en las plumas de aves residentes y migratorias neotropicales, en

sitios selectos de Costa Rica y Panam

ABSTRACT: We non-lethally collected feather samples from resident and migrant birds from

several sites representing different habitats in Costa Rica and Panama to assess if exposure to

mercury (Hg) and/or other heavy metals are of concern at these sites. Of 43 species sampled

in Costa Rica and nine in Panama, mercury exposure was in generally low at all sites. The

American pygmy kingfisher (Chloroceryle aenea) had the highest mercury levels of all birds

sampled, ranging from 2.8 to 5.7 ppm (parts per million) in Panama to 11 ppm at Cao Palma

Research Station in Barra del Colorado Wildlife Refuge, Costa Rica. Feather mercury

concentrations over 4.6 ppm are considered elevated in songbirds (Jackson et al. 2011) and

over 40 ppm in fish-eating birds (Evers et al. 2008). Invertivorous neotropical migrantssuch

as the northern waterthrush (Seiurus noveboracencis), spotted sandpiper (Actitis macularius)

and piscivorous species such as resident kingfishers foraging in aquatic habitats (ie. streams

and mangroves) tended to have higher feather mercury concentrations than other species.

A subset of feather samples (n = 39) were analyzed for other metals including several

essential elements. Here we focus on selected metals that were elevated in sampled birds:

aluminum (Al), barium (Ba), copper (Cu), iron (Fe), manganese (Mn), strontium (Sr), tin (Sn)

and zinc (Zn).

ACKNOWLEDGEMENTS

We are grateful to Alejandra Martinez and the staff from CATIE, Todd Lewis fromCao Palma Biostation, Costa Rica, biologists Jon Van Dort and Evelyn Paola

Thibodeau, and the staff of the Center for Caribbean Conservation and Reserva

Playa Tortuga all helped with bird capture and banding. We thank Kevin Regan at

BRI for Hg analysis.

American Pygmy Kingfisher (Chloroceryle aenea), resident in Costa Rica and Panama

Figure 1. Study sites in Costa Rica and Panama

INTRODUCTIONHeavy metals are among the most toxic poisons known with the nervous system often being the principal

target. We are unaware of any published studies that address heavy metal exposure to the resident birds

and neotropical migrants of Mesoamerica. Most of the toxicity information available focus on aquatic

organisms, particularly fish, but little has been published on metal toxicity in other vertebrates including

birds.Elevated exposure to Al can be toxic to fish and cause pulmonary and developmental problems. Barium

does not bioaccumulate but at high exposures can induce gastrointestinal distress, muscular paralysis, and

cardiovascular problems at concentrations exceeding 10 ppm (Moore 1991). Toxic effects to birds from

exposure to Cu include reduced growth rates, lowered egg production, and developmental abnormalities

(US EPA 2008). Elevated concentrations of Mn in birds have been known to cause decreased hemoglobin,

anemia, and reduced growth (ATSDR 1991). Elevated levels of Zn can cause mortality, pancreatic

degradation, reduced growth, and decreased weight gain in birds (Eisler 1993, NAS 1980). And mercury, in

its methylated form, is a well known neurotoxin and has been shown to affect reproductive success in birds

(Evers et al. 2008, Jackson et al. in press).

Many studies have surveyed for heavy metals in pelagic sea birds, but fewif anyhave assessed heavy

metal exposure to the resident and migrant birds of Mesoamerica. This study provides an initial survey of

heavy metal concentrations for the region.

METHODSAND STUDY AREAOuter tail feathers (R6) were pulled from birds

captured using mistnets. Birds were released

following sampling at the site of capture. Sampling

was completed between November 15, 2010 and

April 19, 2011. Mercury analysis in feathers wasdone using a Direct Mercury Analyzer (DMA-80) by

Millestone Inc. at Biodiversity Research Institute

Wildlife Mercury Research Lab in Maine, USA.

Trace metal scan was done using ICP-MS at the

Trace Element Research Lab at Texas A&M

University, Texas, USA.

In Costa Rica we sampled 2 sites in the lowlands

on the Caribbean Coast near Tortuguero (Cao

Palma and Tortuguero), one site in a cacao

plantation near Volcan Turrialbo (CATIE), one site in

San Jose (INBio Parque) and one site on the Pacific

Coast in the wetlands of Ojochal (Reserva Playa

Tortuga). In Panama three mangrove sites were

sampled on the Atlantic coast (Playa Bonita,

Panama Vieja and Juan Diaz; Figure 1).

RESULTSSee table 1 for metal concentrations by site

and individuals, and figures 2 and 3 for

summary of selected heavy metals by site

and species. Due to lack of funding only a

few samples were screened for heavy

metals. This study serves as a pilot

screening to determine if further sampling is

necessary to assess contaminant exposure to

birds and other wildlife in Central America

and to locate sources of contamination.

Table 1. Concentrations of heavy metals in bird feathers (ppm or mg/kg) from Costa Rica and Panama (numbers in re

we consider high or elevated; species in bold are considered residents).

LITERATURECITED

Evers, D. C., L. Savoy, C. DeSorbo, D. Yates, W. Hanson, K. Taylor, L. Siegel,J. Cooley, M. Bank, A. Major, K. Munney, B. Mower, H. Vogel, N.

Schoch, M. Pokras, M. Goodale, and J. Fair. 2008. Adverse effects

from environmental mercury loads on breeding common loons.

Ecotoxicology 17:69-81.

Jackson, A. K., D. C. Evers, M. A. Etterson, A. M. Condon, S. B. Folsom, J.

Detweiler, J. Schmerfeld, D. A. Cristol. 2011. Mercury exposure

affects the reproductive success of a free-living terrestrial songbird,

the Carolina wren (Thryothorus l udovicianus). The Auk. In press.

DISCUSSIONCertain species, such as the spotted

sandpiper, appear to have elevated levels of

several toxic elements including copper (Cu),

manganese (Mn), Tin (Sn) and mercury (Hg).

In addition to exposure through diet,

shorebirds may ingest a portion of the

metals by consuming contaminated

sediment while foraging. Many heavy metals

are also used in pesticides and

manufacturing and birds may occupy

agricultural habitats or areas downstream

from polluted areas allowing for exposure to

many contaminants.

It appears that further investigation into

contaminant exposure to birds in Central

America is warranted based on these

preliminary data.

Figure 2. Concentrations of trace elements in tail feathers of

individual spotted sandpipers in Costa Rica and Panama.

Figure 3. Mercury concentrations in feathers of kingfishers from Costa

Rica and Panama.

RESUMEN: no letales recogieron muestras de plumas de aves residentes y migratorias de varios sitios que

representan los diferentes hbitats en Costa Rica y Panam para evaluar si la exposicin al mercurio (Hg) y

/ u otros metales pesados son motivo de preocupacin en estos sitios. De 43 especies muestreadas en

Costa Rica y nueve en Panam, la exposicin al mercurio fue en general baja en todos los sitios. El martn

pescador estadounidense enano (Chloroceryle aenea) tenan los niveles ms altos de mercurio de todas

lasaves objeto de muestreo, que van desde 2,8 hasta 5,7 ppm (partes por milln)en Panam a 11 ppm en

Cao Palma Estacin de Investigacin en Barra del Colorado Wildlife Refuge, Costa Rica. Concentraciones

de mercurio en plumas de ms de 4,6 ppm se consideran elevadas en aves cantoras (Jackson et al. 2011) y

ms de 40 ppm en aves piscvoras (Evers et al. 2008). Invertivorous migrantes neotropicales, tales como

el waterthrush norte (Seiurus noveboracencis), playero manchado (Actitis macularius) y las especies se

alimentan de peces como el martn pescador residente de alimentacin en los hbitats acuticos (ros y

manglares es decir), tendan a tener mayores concentraciones de mercurio que otras especies de

plumas. Un subconjunto de muestras de plumas (n = 39) fueron analizadas por otros metales incluyendo

varios elementos esenciales. Aqu nos centramos en los metales seleccionados que fueron elevados

en aves objeto de muestreo: de aluminio (Al), bario (Ba), cobre (Cu), hierro (Fe), manganeso (Mn),

estroncio (Sr), estao (Sn) y zinc (Zn).

0

2

4

6

8

10

12

American Pygmy Kingfisher

(Chloroceryle aenea)

Green and Rufous

Kingfisher (Chloroceryle

inda)

Green Kingfisher

(Chloroceryle americana)

Juan Diaz, Panama (3; 1)

Cao Palma, Costa Rica (1)

Rio Balso, Ojochal, Costa Rica (1)

Feather

Mercury(ppmf

w)

Site Species Al Ba Cu Hg Mn Sn Sr Zn

Cao Palma, CR American Pygmy kingfisher 9.5 0.81 9.87 11.29 2.98 3.62 2.29 141

Northern waterthrush 10.7 1.96 5.62 2.20 14.9 1.29 1.43 119

Red-capped manakin 90.6 3.39 7.9 0.50 24.2 3.91 2.73 106

S ummer t an ager 3 1. 7 4. 41 5.9 7 0. 09 13. 5 3.6 5 1 .31 1 04

Swainson's thrush 13.1 2.09 6.57 0.50 8.86 3.85 1.25 97.7

Swainson's thrush 52.2 2.35 6.68 0.19 12.8 2.28 1.57 93.7

White-collared manakin 50.2 4.83 6.36 0.35 8.67 3.3 2.76 109

Wood thrush 260 7.86 7.92 1.89 47.8 2.22 4.62 96.1

Wood thrush 342 9.01 6.53 1.67 37.9 2.15 4.1 95.2Tortuguero, CR Swainson's thrush 36.3 3.9 9.58 1.02 9.98 3.36 1.51 102

Yellow bell ied flycatcher 10.6 3.83 6.2 1.26 40 3.31 2.02 96.6

CATIE, CR Baltimore oriole 288 6.34 8.34 0.27 15.3 2.06 4.61 61.2

Chesnut-sided warbler 21.8 2.83 6.66 12.4 4.18 1.23 110

Passarin's tanager 458 25.5 7.33 0.08 52.9 2.1 5 1 1 10 3

Yellow-throated euphonia 61 31.9 5.3 0.06 8.87 4.24 8.63 100

In Bi o, S an Jose, CR N ort hern wa tert hru sh 3 1. 8 2. 03 1 9. 6 1. 24 1 7. 5 2.5 7 2.58 9 6. 8

Philadelphia v ireo 56.3 1.56 6.59 0.21 1.43 4.32 1.12 90.2

Reserva Play Tortuga, Ojochal, CR Black-hooded antshrike 20.1 4.25 7.43 0.03 19.6 5.13 5.28 154

Blue-grey tanager 34.2 7.19 7.14