, Volume 28, Issue 4, pp 379–391 | Cite as

Feather mercury concentrations in North American raptors sampled at migration monitoring stations

  • Ryan P. BourbourEmail author
  • Breanna L. Martinico
  • Joshua T. Ackerman
  • Mark P. Herzog
  • Angus C. Hull
  • Allen M. Fish
  • Joshua M. Hull


We assessed total mercury (THg) concentrations in breast feathers of diurnal North American raptors collected at migration monitoring stations. For 9 species in the Pacific Flyway, we found species and age influenced feather THg concentrations whereas sex did not. Feather THg concentrations µg/g dry weight (dw) averaged (least squares mean ± standard error) higher for raptors that generally consume > 75% avian prey (sharp-shinned hawk Accipiter striatus: n = 113; 4.35 ± 0.45 µg/g dw, peregrine falcon Falco peregrinus: n = 12; 3.93 ± 1.11 µg/g dw, Cooper’s hawk Accipiter cooperii: n = 20; 2.35 ± 0.50 µg/g dw, and merlin Falco columbarius: n = 59; 1.75 ± 0.28 µg/g dw) than for raptors that generally consume < 75% avian prey (northern harrier Circus hudsonius: n = 112; 0.75 ± 0.10 µg/g dw, red-tailed hawk Buteo jamaicensis: n = 109; 0.56 ± 0.06 µg/g dw, American kestrel Falco sparverius: n = 16; 0.57 ± 0.14 µg/g dw, prairie falcon Falco mexicanus: n = 10; 0.41 ± 0.13 µg/g dw) except for red-shouldered hawks Buteo lineatus: n = 10; 1.94 ± 0.61 µg/g dw. Feather THg concentrations spanning 13-years (2002–2014) in the Pacific Flyway differed among 3 species, where THg increased for juvenile northern harrier, decreased for adult red-tailed hawk, and showed no trend for adult sharp-shinned hawk. Mean feather THg concentrations in juvenile merlin were greater in the Mississippi Flyway (n = 56; 2.14 ± 0.18 µg/g dw) than those in the Pacific Flyway (n = 49; 1.15 ± 0.11 µg/g dw) and Intermountain Flyway (n = 23; 1.14 ± 0.16 µg/g dw), and Atlantic Flyway (n = 38; 1.75 ± 0.19 µg/g dw) averaged greater than the Pacific Flyway. Our results indicate that raptor migration monitoring stations provide a cost-effective sampling opportunity for biomonitoring environmental contaminants within and between distinct migration corridors and across time.


Raptor Contaminants Biomagnification Biomonitoring Migration Methylmercury 



This research was partially funded by the U.S. Geological Survey Environmental Health Mission Area’s Contaminant Biology Program. We thank Matt Toney and Sarah Peterson for lab analyses. The use of trade, product, or firm names in the publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Feather sample contributors: Golden Gate Raptor Observatory, HawkWatch International, Cape May Bird Observatory, Hawk Ridge Bird Observatory. We thank Ryan Phillips, Sara Kross, Megan Crane, Autumn Iverson, Brian Hoover, and Chris Tyson for feedback and support.


Funding was provided to J.T.A. by the U.S. Geological Survey Environmental Health Mission Area’s Contaminant Biology Program.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

All national and institutional guidelines for the care and use of animals were followed. All raptor handling and feather collections were in compliance with the Golden Gate Raptor Observatory standards as described in their Institutional Animal Care and Use Committee protocols. This article does not contain any studies with human participants performed by any of the authors.


  1. Ackerman JT, Eagles-Smith CA, Takekawa JY, Demers SA, Adelsbach TL, Bluso JD, Miles AK, Warnock N, Suchanek TH, Schwarzbach SE (2007) Mercury concentrations and space use of pre-breeding American avocets and black-necked stilts in San Francisco Bay. Sci Total Environ 384:452–466Google Scholar
  2. Ackerman JT, Eagles-Smith CA, Takekawa JY, Bluso JD, Adelsbach TL (2008) Mercury concentrations in blood and feathers of prebreeding Forster’s terns in relation to space use of San Francisco Bay, California, USA, habitats. Environ Toxicol Chem 27:897–908Google Scholar
  3. Ackerman JT, Eagles-Smith CA, Herzog MP (2011) Bird mercury concentrations change rapidly as chicks age: toxicological risk is highest at hatching and fledging. Environ Sci Technol 45:5418–5425Google Scholar
  4. Ackerman JT, Overton CT, Casazza ML, Takekawa JY, Eagles-Smith CA, Keister RA, Herzog MP (2012) Does mercury contamination reduce body condition of endangered California clapper rails? Environ Pollut 162:439–448Google Scholar
  5. Ackerman JT, Eagles-Smith CA, Herzog MP, Hartman CA, Peterson SH, Evers DC, Bryan CE (2016a) Avian mercury exposure and toxicological risk across western North America: a synthesis. Sci Total Environ 568:749–769Google Scholar
  6. Ackerman JT, Eagles-Smith CA, Herzog MP, Hartman CA (2016b) Maternal transfer of contaminants in birds: mercury and selenium concentrations in parents and their eggs. Environ Pollut 210:145–154Google Scholar
  7. Albers PH, Koterba MT, Rossmann R, Link WA, French JB, Bennett RS, Bauer WC (2007) Effects of methylmercury on reproduction in American kestrels. Environ Toxicol Chem 26(9):1856–1866Google Scholar
  8. Barnes JG, Gerstenberger SL (2015) Using feathers to determine mercury contamination in peregrine falcons and their prey. J Raptor Res 49(1):43–58Google Scholar
  9. Barnes JG, Varland DE, Buchanan JB, Fleming TL, Gerstenberger SL (2018) Mercury contamination in Peregrine Falcons (Falco peregrinus) in coastal Washington, 2001–2016. Wilson J Ornithol 130(4):958–968Google Scholar
  10. Bechard MJ, Perkins DN, Kaltenecker GS, Alsup S (2009) Mercury contamination in Idaho bald eagles, Haliaeetus leucocephalus. Bull Environ Contam Toxicol 83(5):698Google Scholar
  11. Becker DJ, Chumchal MM, Broders HG, Korstian JM, Clare EL, Rainwater TR, Fenton MB (2018) Mercury bioaccumulation in bats reflects dietary connectivity to aquatic food webs. Environ Pollut 233:1076–1085Google Scholar
  12. Bildstein KL (1992) Causes and consequences of reversed sexual size dimorphism in raptors: the head-start hypothesis. J Raptor Res 26(3):115–123Google Scholar
  13. Bildstein KL, Meyer KD (2000) Sharp-shinned Hawk (Accipiter striatus), version 2.0. In: The Birds of North America (Poole AF, Gill FB, eds). Cornell Lab of Ornithology, Ithaca, NY, USA.
  14. Bloom PH, McCrary MD, Gibson MJ (1993). Red-shouldered Hawk home-range and habitat use in southern California. J Wildl Manage, 57(2):258–265Google Scholar
  15. Bond AL, Hobson KA, Branfireun BA (2015) Rapidly increasing methyl mercury in endangered ivory gull (Pagophila eburnea) feathers over a 130 year record Proc R Soc Lond B 282(1805):20150032Google Scholar
  16. Bowerman WW, Evans ED, Giesy JP, Postupalsky S (1994) Using feathers to assess risk of mercury and selenium to bald eagle reproduction in the Great Lakes region. Arch Environ Contam Toxicol 27(3):294–298Google Scholar
  17. Breheny P, Burchett W (2017) Visualization of regression models using visreg. R J 9:56–71Google Scholar
  18. Bustnes JO, Bårdsen BJ, Bangjord G, Lierhagen S, Yoccoz NG (2013) Temporal trends (1986–2005) of essential and non-essential elements in a terrestrial raptor in northern Europe. Sci Total Environ 458:101–106Google Scholar
  19. Castro I, Aboal JR, Fernández JA, Carballeira A (2011) Use of raptors for biomonitoring of heavy metals: gender, age and tissue selection. Bull Environ Contam Toxicol 86(3):347–351Google Scholar
  20. Cristol DA, Mojica EK, Varian-Ramos CW, Watts BD (2012) Molted feathers indicate low mercury in bald eagles of the Chesapeake Bay, USA. Ecol Indic 18:20–24Google Scholar
  21. Cristol DA, Brasso RL, Condon AM, Fovargue RE, Friedman SL, Hallinger KK, White AE (2008) The movement of aquatic mercury through terrestrial food webs. Science 320(5874):335–335Google Scholar
  22. Curtis OE, Rosenfield RN, Bielefeldt J (2006) Cooper's Hawk (Accipiter cooperii), version 2.0. In: The Birds of North America (Poole AF, Ed). Cornell Lab of Ornithology, Ithaca, NY, USA.
  23. Dauwe T, Bervoets L, Pinxten R, Blust R, Eens M (2003) Variation of heavy metals within and among feathers of birds of prey: effects of molt and external contamination. Environ Pollut 124(3):429–436Google Scholar
  24. De Graaf RM, Tilghman NG, Anderson SH (1985) Foraging guilds of North American birds. Environ Manag 9(6):493–536Google Scholar
  25. DesGranges JL, Rodrigue J, Tardif B, Laperle M (1998) Mercury accumulation and biomagnification in ospreys (Pandion haliaetus) in the James Bay and Hudson Bay regions of Quebec. Arch Environ Contam Toxicol 35(2):330–341Google Scholar
  26. DeSorbo CR, Burgess NM, Todd CS, Evers DC, Bodaly RA, Massey BH, Meattey DE (2018) Mercury concentrations in bald eagles across an impacted watershed in Maine, USA. Sci Total Environ 627:1515–1527Google Scholar
  27. Dykstra CR, Hays JL, Crocoll ST (2008) Red-shouldered Hawk (Buteo lineatus), version 2.0. In: The Birds of North America (Poole AF, Ed.). Cornell Lab of Ornithology, Ithaca, NY, USA,
  28. Espín, S., García-Fernández AJ, Herzke D, Shore RF, van Hattum B, Martínez-López E,… Jaspers VLB (2014) Sampling and contaminant monitoring protocol for raptors. Research Networking Programme-EURAPMON, Research and monitoring for and with raptors in Europe. Available on
  29. Espín S, García-Fernández AJ, Herzke D, Shore RF, van Hattum B, Martínez-López E, Jaspers VLB (2016) Tracking pan-continental trends in environmental contamination using sentinel raptors—what types of samples should we use? Ecotoxicology 25(4):777–801Google Scholar
  30. Evers DC, Kaplan JD, Meyer MW, Reaman PS, Braselton WE, Major A et al. (1998) Geographic trend in mercury measured in common loon feathers and blood. Environ Toxicol Chem 17(2):173–183Google Scholar
  31. Evers DC, Burgess NM, Champoux L, Hoskins B, Major A, Goodale WM et al. (2005) Patterns and interpretation of mercury exposure in freshwater avian communities in northeastern North America. Ecotoxicology 14(1-2):193–221Google Scholar
  32. Fitzgerald WF, Engstrom DR, Mason RP, Nater EA (1998) The case for atmospheric mercury contamination in remote areas. Environ Sci Technol 32(1):1–7Google Scholar
  33. Furness RW, Muirhead SJ, Woodburn M (1986) Using bird feathers to measure mercury in the environment: relationships between mercury content and moult. Mar Pollut Bull 17(1):27–30Google Scholar
  34. García-Seoane R, Varela Z, Carballeira A, Aboal JR Fernández JÁ (2017) Temporal trends in mercury concentrations in raptor flight feathers stored in an environmental specimen bank in Galicia (NW Spain) between 2000 and 2013. Ecotoxicology 26(2):196–201Google Scholar
  35. Golden Gate Raptor Observatory (GGRO) (1998) Bander's manual, 3rd edn, National Park Service/Golden Gate National Parks Conservancy, Sausalito, CA, pp. 73.Google Scholar
  36. Golden Gate Raptor Observatory (GGRO) (2015) Pacific raptor report, 37. Fall migration. Golden Gate Raptor Observatory.Google Scholar
  37. Gómez-Ramírez P, Shore RF, Van Den Brink NW, Van Hattum B, Bustnes JO, Duke G et al. (2014) An overview of existing raptor contaminant monitoring activities in Europe. Environ Int 67:12–21Google Scholar
  38. Goodrich LJ, Smith JP (2008) Raptor migration in North America. In: State of North America's Birds of Prey (Bildstein KL, Smith JP, Ruelas Inzunza E, Veit RR, Eds.), Nuttall Ornithological Club, Cambridge, and American Ornithologists’ Union, Washington. pp. 37–149Google Scholar
  39. Goodrich LJ, Crocoll ST, Senner SE (2014) Broad-winged Hawk (Buteo platypterus), version 2.0. In: The birds of North America (Poole AF, Ed.). Cornell Lab of Ornithology, Ithaca, NY, USA,
  40. Guigueno MF, Elliott KH, Levac J, Wayland M, Elliott JE (2012) Differential exposure of alpine ospreys to mercury: melting glaciers, hydrology or deposition patterns? Environ Int 40:24–32Google Scholar
  41. Gunnarsson B (2007) Bird predation on spiders: ecological mechanisms and evolutionary consequences. J Arachnol 35(3):509–529Google Scholar
  42. Heinz GH, Hoffman DJ, Klimstra JD, Stebbins KR (2009) Rapid increases in mercury concentrations in the eggs of mallards fed methylmercury. Environ Toxicol Chem 28(9):1979–1981Google Scholar
  43. Henny CJ, Grove RA, Kaiser JL, Johnson BL (2010) North American osprey populations and contaminants: historic and contemporary perspectives. J Toxicol Environ Health Part B 13(7–8):579–603Google Scholar
  44. Herring G, Eagles-Smith CA, Ackerman JT (2017) Mercury exposure may influence fluctuating asymmetry in waterbirds. Environ Toxicol Chem 36(6):1599–1605Google Scholar
  45. Howie MG, Jackson AK, Cristol DA (2018) Spatial extent of mercury contamination in birds and their prey on the floodplain of a contaminated river. Sci Total Environ 630:1446–1452Google Scholar
  46. Hull JM, Girman DJ (2005) Effects of Holocene climate change on the historical demography of migrating sharp-shinned hawks (Accipiter striatus velox) in North America. Mol Ecol 14(1):159–170Google Scholar
  47. Hull JM, Strobel BN, Boal CW, Hull AC, Dykstra CR, Irish AM, Fish AM, Ernest HB (2008a) Comparative phylogeography and population genetics within Buteo lineatus reveals evidence of distinct evolutionary lineages. Mol Phylogenet Evol 49(3):988–996Google Scholar
  48. Hull JM, Hull AC, Sacks BN, Smith JP, Ernest HB (2008b) Landscape characteristics influence morphological and genetic differentiation in a widespread raptor (Buteo jamaicensis). Mol Ecol 17(3):810–824Google Scholar
  49. Hull JM, Ernest HB, Harley JA, Fish AM, Hull AC (2009) Differential migration between discrete populations of juvenile Red-tailed Hawks (Buteo jamaicensis). Auk 126(2):389–396Google Scholar
  50. Judd SD (1901) The relation of sparrows to agriculture. U.S. Department of Agriculture Division of Biological Survey, Government Printing Office, WashingtonGoogle Scholar
  51. Keith JA, Gruchy IM (1972) Residue levels of chemical pollutants in North American birdlife. In: Proceedings of the 15th International Ornithological Congress, The Hague, 1970.Google Scholar
  52. Keyel, E. R. (2016) Mercury accumulation in raptors. Doctoral dissertation, University of Minnesota.Google Scholar
  53. Lenth RV (2016) Least-squares means: the R package is means. J Stat Softw 69(1):1–33. Google Scholar
  54. Lewis SA, Furness RW (1993) The role of eggs in mercury excretion by quail Coturnix coturnix and the implications for monitoring mercury pollution by analysis of feathers. Ecotoxicology 2(1):55–64Google Scholar
  55. Lindberg P (1984) Mercury in feathers of Swedish gyrfalcons, Falco rusticolus, in relation to diet. Bull Environ Contam Toxicol 32(1):453–459Google Scholar
  56. Lodenius M, Solonen T (2013) The use of feathers of birds of prey as indicators of metal pollution. Ecotoxicology 22(9):1319–1334Google Scholar
  57. Lourenço R, Tavares PC, del Mar Delgado M, Rabaça JE, Penteriani V (2011) Superpredation increases mercury levels in a generalist top predator, the eagle owl. Ecotoxicology 20(4):635–642Google Scholar
  58. Movalli PA (2000) Heavy metal and other residues in feathers of laggar falcon Falco biarmicus jugger from six districts of Pakistan. Environ Pollut 109(2):267–275Google Scholar
  59. Obrist D, Kirk JL, Zhang L, Sunderland EM, Jiskra M, Selin NE (2018) A review of global environmental mercury processes in response to human and natural perturbations: changes of emissions, climate, and land use. Ambio 47(2):116–140Google Scholar
  60. Palma L, Beja P, Tavares PC, Monteiro LR (2005) Spatial variation of mercury levels in nesting Bonelli’s eagles from Southwest Portugal: effects of diet composition and prey contamination. Environ Pollut 134(3):549–557Google Scholar
  61. Peeters H, Peeters P (2005) Raptors of California. University of California Press Ltd, London, UK.Google Scholar
  62. Pitzer S, Hull J, Ernest HB, Hull AC (2008) Sex determination of three raptor species using morphology and molecular techniques. J Field Ornithol 79(1):71–79Google Scholar
  63. Preston CR, Beane RD (2009) Red-tailed Hawk (Buteo jamaicensis), version 2.0. In: The birds of North America (Poole AF, Ed.). Cornell Lab of Ornithology, Ithaca, NY, USA,
  64. RStudio Team (2015) RStudio: integrated development for R. RStudio, Inc., Boston, MA.
  65. Rimmer CC, Miller EK, McFarland KP, Taylor RJ, Faccio SD (2010) Mercury bioaccumulation and trophic transfer in the terrestrial food web of a montane forest. Ecotoxicology 19(4):697–709Google Scholar
  66. Robinson SA, Forbes MR, Hebert CE, Scheuhammer AM (2011) Evidence for sex differences in mercury dynamics in double-crested cormorants. Environ Sci Technol 45:1213–1218Google Scholar
  67. Rottenborn SC (2000) Nest-site selection and reproductive success of urban Red-shouldered Hawks in central California. J Raptor Res 34(1):18–25Google Scholar
  68. Roque I, Lourenço R, Marques A, Coelho JP, Coelho C, Pereira E, Roulin A (2016) Barn owl feathers as biomonitors of mercury: sources of variation in sampling procedures. Ecotoxicology 25(3):469–480Google Scholar
  69. Scheuhammer AM, Meyer MW, Sandheinrich MB, Murray MW (2007) Effects of environmental methylmercury on the health of wild birds, mammals, and fish. AMBIO 36(1):12–19Google Scholar
  70. Seber GAF (1982) The estimation of animal abundance and related parameters, 2nd edn. Macmillan, New York, NYGoogle Scholar
  71. Smallwood JA, Bird DM (2002) American Kestrel (Falco sparverius), version 2.0. In: The birds of North America (Poole AF, Gill FB, eds.). Cornell Lab of Ornithology, Ithaca, NY, USA,
  72. Smith KG, Wittenberg SR, Macwhirter RB, Bildstein KL (2011) Hen/Northern Harrier (Circus cyaneus/hudsonius), version 2.0. In: The birds of North America (Poole AF, Ed.). Cornell Lab of Ornithology, Ithaca, NY, USA,
  73. Smith TB, Marra PP, Webster MS, Lovette I, Gibbs HL, Holmes RT, Rohwer S (2003) A call for feather sampling. Auk 120(1):218–221Google Scholar
  74. Snyder NF, Wiley JW (1976) Sexual size dimorphism in hawks and owls of North America. Ornithol Monogr 20:1–95.Google Scholar
  75. Steenhof K (2013) Prairie Falcon (Falco mexicanus), version 2.0. In: The birds of North America (Poole AF, Ed.). Cornell Lab of Ornithology, Ithaca, NY, USA,
  76. Townsend JM, Rimmer CC, Driscoll CT, McFarland KP, Inigo-Elias E (2013) Mercury concentrations in tropical resident and migrant songbirds on Hispaniola. Ecotoxicology 22(1):86–93Google Scholar
  77. United States Environmental Protection Agency (U.S. EPA) 1998 Mercury in solids and solutions by thermal decomposition, amalgamation, and atomic absorption spectrophotometry. EPA Method 7473 Report, January 1998. p.15Google Scholar
  78. Varela Z, García-Seoane R, Fernández JA, Carballeira A, Aboal JR (2016) Study of temporal trends in mercury concentrations in the primary flight feathers of Strix aluco. Ecotoxicol Environ Saf 130:199–206Google Scholar
  79. Walker LA, Shore RF, Turk A, Pereira MG, Best J (2008) The predatory bird monitoring scheme: identifying chemical risks to top predators in Britain. AMBIO: A J Human Environ 37(6):466–471Google Scholar
  80. Warkentin IG, Sodhi NS, Espie RHM, Poole AF, Oliphant LW, James. PC (2005) Merlin (Falco columbarius), version 2.0. In: The birds of North America (Poole AF ed.). Cornell Lab of Ornithology, Ithaca, NY, USA,
  81. Weech SA, Scheuhammer AM, Elliott JE (2006) Mercury exposure and reproduction in fish-eating birds breeding in the Pinchi Lake region, British Columbia, Canada. Environ Toxicol Chem 25(5):1433–1440Google Scholar
  82. Weir SM, Thomas JF, Blauch DN (2018) Investigating spatial patterns of mercury and rodenticide residues in raptors collected near the Charlotte, NC, USA, metropolitan area. Environ Sci Pollut Res 25(33):33153–33161Google Scholar
  83. White CM, Clum NJ, Cade TJ, Hunt WG (2002) Peregrine Falcon (Falco peregrinus), version 2.0. In: The birds of North America (Poole AF, Gill FB, eds.). Cornell Lab of Ornithology, Ithaca, NY, USA,
  84. Wiener JG, Krabbenhoft DP, Heinz GH, Scheuhammer AM (2003) Ecotoxicology of mercury. Handb Ecotoxicol 2:409–463Google Scholar
  85. Wolfe MF, Schwarzbach S, Sulaiman RA (1998) Effects of mercury on wildlife: a comprehensive review. Environ Toxicol Chem 17(2):146–160Google Scholar
  86. Zolfaghari G, Esmaili-Sari A, Ghasempouri SM, Kiabi BH (2007) Examination of mercury concentration in the feathers of 18 species of birds in southwest Iran. Environ Res 104(2):258–265Google Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Animal ScienceUniversity of California, DavisDavisUSA
  2. 2.U.S. Geological SurveyWestern Ecological Research CenterDixonUSA
  3. 3.Golden Gate Raptor ObservatorySausalitoUSA

Personalised recommendations