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Avian ecology and conservation in a time of global change

Our lab addresses questions about how birds respond to environmental change. We use physiological and behavioral ecology approaches to understand mechanisms underlying responses at the individual-level, and population ecology and modeling to understand impacts on populations.  Most of our research focuses on avian reproduction or migration, and current studies are designed to explore effects of global change across the full annual cycle. Studies that increase understanding about the links between environmental conditions, physiological or behavioral responses, and impacts on survival and reproduction, inform wildlife management and aid in biodiversity conservation in a rapidly changing world.

Please check out our partnership to study birds year-round, across their North American range. To learn more please visit


Climate Change

Over the past 27 years winter severity has decreased in southwestern Idaho and, in that same time period, the average American Kestrel nest initiation date has advanced by 28 days. We hypothesize that warmer winters have removed constraints that previously precluded early nest initiation. For birds, these constraints include: 1) migration away from breeding areas with severe winters and 2) the allocation of energetic reserves to thermoregulation instead of gamete production. Once these constraints are removed, nest initiation dates may have advanced rapidly because of an underlying pattern of higher early-season reproductive success that is common in most temperate breeding birds. We are investigating whether decreased winter severity affects the proportion of birds that overwinter in the breeding area and female attainment of reproductive condition.

Human Disturbance

Raptors and other birds that live in human-modified landscapes may be exposed to high levels of human disturbance.  Birds may respond to this disturbance with habituation, dispersal away from the disturbance, or perhaps, they may maintain a chronic state of stress.  Long term exposure to stressful situations can affect reproduction and survival. We are interested in understanding how raptors and other birds respond to human disturbance and whether this response affects individual fitness and population trends.

Landscape Change

Invasive species, climate, development, and fire can contribute to rapid landscape change that has consequences for raptors and other wildlife.  Our lab is collaborating with USGS scientists and the US Fish and Wildlife Service to understand how golden eagle diets may have shifted in response to changing landscapes.


Ranck, S., C.M. Garsvo, D.M. Schwartz, L.M. Reynard, M.J. Kohn, and J.A. Heath. 2023. Sex, body size, and winter weather explain migration strategies in a partial migrant population of American Kestrels (Falco sparverius). Ornithology 140:1-10.

Hunt, A.J., J. Watson, J.W. Winiarski, R. Porter, and J.A. Heath. 2023. American Kestrel Migration: Insights and challenges from tracking individuals across the annual cycle. Journal of Raptor Research 57:164-175.

Bossu, C.M., J.A. Heath, B. Helm, G.M. Kaltenecker, and K.C. Ruegg. 2022. Clock-linked genes underlie seasonal migratory timing in a diurnal raptor. Proceedings of the Royal Society B 289: 20212507.

Callery, K.R., S.E. Schulwitz, A.R. Hunt, J.M. Winiarski, C.J.W. McClure, R.A. Fischer, J.A. Heath. 2022. Phenology effects on productivity and hatching-asynchrony of American kestrels (Falco sparverius) across a continent. Global Ecology and Conservation 36: e02124.

Callery, K.R., J.A. Smallwood, A.R. Hunt, E.R. Snyder, and J.A. Heath. 2022. Seasonal trends in adult survival and reproductive trade-offs reveal potential constraints to earlier nesting in a migratory bird. Oecologia 199:91–102.

Galla, S.J., L. Brown, Y. Couch-Lewis (Ngāi Tahu: Te Hapū o Ngāti Wheke, Ngāti Waewae), I. Cubrinovska, D. Eason, R.M. Gooley, J.A. Hamilton, J.A. Heath, S.S. Hauser, E.K. Latch, M. D. Matocq, A. Richardson, J.R. Wold, C.J. Hogg, A.W. Santure, and T.E. Steeves. 2022. The relevance of pedigrees in the conservation genomics era. Molecular Ecology 31: 41– 54.

McClure, C.J.W., D. L. Anderson, J. R. Belthoff, A. Botha, E.R. Buechley, R. Buij, R.A.G. Davies, L. Dunn, L. Glowka, L. Goodrich, S. Gurung, J.A. Heath, M.T. Henderson, S. Hinchliffe, F. Loercher, J. McCabe, D. Méndez, E.B.P. Miranda, M.D. Oleyar, W.L. Phipps, A.P. Rayner, C. Marques Reyes, B.W. Robinson, B.W. Rolek, S.E. Schulwitz, S. Slater, D.P. Spurling, T.R. Subedi, P. Sumasgutner, L.J. Sutton, J. Tavares, J.-F. Therrien, S.R. Trice, F.H. Vargas, M.Z. Virani, and R.T. Watson. 2021. Commentary: The past, present, and future of the global raptor impact network. Journal of Raptor Research. 55(4)

Dudek, B.M., M. T. Henderson, S.F. Hudon, E.J. Hayden, J.A. Heath. 2021. Hematophagous ectoparasites lower survival of and have detrimental physiological effects on golden eagle nestlings. Conservation Physiology. 9:1.

Heath, J.A., M. N. Kochert, and K. Steenhof. 2021.  Golden Eagle dietary shifts following wildfire and shrub loss have negative consequences for nestling survivorship. Ornithological Applications .

Powers, B.F., J.M. Winiarski, J.M. Requena-Mullo, J.A. Heath. 2021. Intra-specific variation in migration phenology of American Kestrels (Falco sparverius) in response to spring temperatures. Ibis. 163:1448-1456.

Opdahl, E.D., K. Demps, J.A. Heath. 2021. Decreased cortisol among hikers who preferentially visit and value biodiverse riparian zones.  Scientific Reports 11:848

McClure, C.J.W., J. Brown, S.E. Schulwitz, J. Smallwood, K.E. Farley, J.-F. Therrien, K. Miller, K. Steenhof, J.A. Heath. 2021. Demography of a widespread raptor varies across disparate regions. Ibis. 163:658-670

Ruegg, K.C., M.S. Brinkmeyer, C.M. Bossu, R. Bay, E.C. Anderson, C.W. Boal, R.D. Dawson, A. Eschenbauch, C.J.W. McClure, K.E. Miller, L. Morrow, J. Morrow, M. D. Oleyar, B. Ralph, S. Schulwitz, T. Swem, J.-F. Therrien, T.B. Smith, J.A. Heath. 2021. The American kestrel genoscape (Falco sparverius): Implications for monitoring, management, and subspecies boundaries. Ornithology 138:1-14.

Katzner, T.E., J.D. Carlisle, S.A. Poessel1, E.C. Thomason, B.P. Pauli, D.S. Pilliod, J.R. Belthoff, J. A. Heath, K.J. Parker, K.S. Warner, H. Hayes, M. Aberg, P.A. Ortiz, S.M. Amdor, S.E. Alsup, S.E. Coates, T.A. Miller, Z.K.T. Duran. 2020. Illegal killing of non-game wildlife and recreational shooting in conservation areas. Conservation Science and Practice.

Hudon, S.F., E.P. Hurtado, J.D. Beck, S.J. Burden, D.P. Bendixsen, K.R. Callery, J.S. Forbey, L.P. Waits, R.A. Miller, Ó. K. Nielsen, J.A. Heath, E.J. Hayden. 2020. Primers to highly conserved elements optimized for qPCR-based telomere length measurements in vertebrates. Molecular Ecology Resources. doi:10.1111/1755-0998.13238

McCaslin, H.M., T.T. Caughlin, and J.A. Heath. 2020.  Long-distance natal dispersal is relatively frequent and correlated with environmental factors in a widespread raptor. Journal of Animal Ecology 89: 2077– 2088.

Herring, G., C.A. Eagles-Smith, J. Buck, A. Shiel, C. Vennum, C. Emery, B. Johnson, D. Leal, J. A. Heath, B.M. Dudek, C. Preston, and B. Woodbridge. 2020. The Lead (Pb) lining of agriculture-related subsidies: enhanced Golden Eagle growth rates tempered by Pb exposure. Ecosphere 11:1

McCaslin, H.M., and J.A. Heath. 2020.  Patterns and mechanisms of heterogeneous breeding distribution shifts of North American migratory birds. Journal of Avian Biology. 51:3

Pauli, B.P., E. Sun, Z. Tinkle, J. Forbey, K. Demps, and J.A. Heath. 2019.  Human habitat selection: Using tools from wildlife ecology to predict recreation in natural landscapes. Natural Areas Journal 39:142-149.

Harrison, J.T., M Kochert, B.P. Pauli and J.A. Heath. 2019.  Using motion-activated trail cameras to study diet and productivity of cliff-nesting golden eagles.  Journal of Raptor Research 53:26-37.

Dudek, B.M., M.N. Kochert, J.G. Barnes, P.H. Bloom, J.M. Papp, R.W. Gerhold, K.E. Purple, K.V. Jacobson, C.R. Preston, C.R. Vennum, J.W. Watson, J.A. Heath. 2018.  Prevalence and risk factors of Trichomonas gallinae and trichomonosis in Golden Eagle (Aquila chrysaetos) nestlings in Western North America.  Journal of Wildlife Diseases. DOI: 10.7589/2017-11-271

D’Acunto, L.E., R.J. Spaul, J.A. Heath, and P.A. Zollner. 2018. Simulating the success of trail closure strategies on reducing human disturbance to Golden Eagles. The Condor: Ornithological Applications 120(3):703-718.

Frey, E., K. Demps, B. P. Pauli, and J.A. Heath. 2018. Group characteristics influence distribution patterns of off-road vehicle recreation within a complex trail system in southwest Idaho. Leisure Sciences 40:1-20.

Spaul, R.J. and J.A. Heath. 2017. Flushing responses of Golden Eagles (Aquila chrysaetos) in response to recreation. Wilson Journal of Ornithology. 129(4):834-845.

McClure, C.J.W., S.E. Schulwitz, R. van Buskirk, B.P. Pauli, and J.A. Heath. 2017.  Commentary: Research recommendations for understanding the decline of American kestrels (Falco sparverius) across much of North America. The Journal of Raptor Research. 51(4):455-464.

Davis, C. M., J. A. Heath, and C. J. W. McClure. 2017. Nest box use by American Kestrels and other cavity-nesting birds during the nonbreeding season. Avian Conservation and Ecology 12(2):5.

MacColl, E., K. Vanesky, J.A. Buck, B.M. Dudek, C.A. Eagles-Smith, J.A. Heath, G. Herring, C. Vennum, C.J. Downs. 2017. Correlates of immune defenses in golden eagle nestlings. Journal of Experimental Zoology, Part A: Ecological and Integrative Physiology. DOI: 10.1002/jez.2081

McClure, C.J.W., B.P. Pauli, and J.A. Heath. 2017. Simulations reveal the power and peril of artificial breeding sites for monitoring and managing animals. Ecological Applications 27(4): 1155-1166. DOI: 10.1002/eap.1509

Smith, S. H., K. Steenhof, C.J.W. McClure, and J.A. Heath. 2017. Earlier nesting by generalist predatory bird is associated with human responses to climate change. Journal of Animal Ecology 86:98-107. DOI: 10.1111/1365-2656.12604

Nolte, E.G., J. Bart, B. P. Pauli, G. S. Kaltenecker, and J.A. Heath. 2016. Detectability of migrating raptors and its effect on bias and precision of trend estimates. Avian Conservation and Ecology 11(2):9.

Spaul, R.J. and J.A. Heath. 2016. Nonmotorized recreation and motorized recreation in shrub-steppe habitats affects behavior and reproduction of golden eagles (Aquila chrysaetos). Ecology and Evolution. DOI: 10.1002/ece3.2540

Pauli, B.P., Spaul, R.J. and J.A. Heath. 2016. Forecasting disturbance effects on wildlife: tolerance does not mitigate effects of increased recreation on wildlands. Animal Conservation. DOI: 10.1111/acv.12308

Anderson, A.M., S.J. Novak, J.F. Smith, K. Steenhof, and J.A. Heath. 2016. Nesting phenology, mate choice, and genetic divergence within a partially migratory population of American kestrels.  Auk: Ornithological Advances 133:99-109.  DOI: 10.1642/AUK-15-129.1

Sassani, E.C. , C. Sevy, E.H. Strasser, A.M. Anderson, and J.A. Heath. 2016Plasma carotenoid concentrations of incubating American kestrels (Falco sparverius) show annual, seasonal, and individual variation and predict reproductive outcome.  Biological Journal of the Linnean Society. 117:414_421. DOI: 10.1111/bij.12653

McClure, C.J.W.,  A.C. Korte, J.A. Heath, and J.R. Barber. 2015. Pavement and riparian forest shape the bird community along an urban river corridor.  Global Ecology and Conservation 4:291-310doi:10.1016/j.gecco.2015.07.004

Paprocki, N., N. Glenn, E. Atkinson, K. Stirckler, C. Watson, and J.A. Heath. 2015.  Changing habitat use associated with distributional shifts of wintering raptors. Journal of Wildlife Management. 79:402–412. DOI: 10.1002/jwmg.848

Miller, R.A., J.D. Carlisle, N. Paprocki, G.S. Kaltenecker, and J.A. Heath. 2015. Annual variation in autumn migration phenology and energetic condition at a stopover site in the western United States. Pp. 177–191 in E. M. Wood and J. L. Kellermann (editors), Phenological synchrony and bird migration: changing climate and seasonal resources in North America. Studies in Avian Biology (no. 47), CRC Press, Boca Raton, FL.  Download Miller et all. 2015 pdf

Paprocki, N., J.A. Heath and S.J. Novak. 2014. Regional distribution shifts help explain local changes in wintering raptor abundance: Implications for interpreting population trends. PLoS One 9(1): e86814. doi: 10.1371/journal.pone.0086814

Steenhof, K. and J.A. Heath. 2013. Local recruitment and natal dispersal distances in American kestrels. The Condor 115:584–592.

Strasser, E.H. and J.A. Heath. 2013. Reproductive failure of a human-tolerant species, the American kestrel, is associated with stress and human disturbance.  Journal of Applied Ecology 50:912-919

Webber, A.F., J.A. Heath, and R.A. Fischer.  2013. Human disturbance and stage-specific habitat requirements influence snowy plover site occupancy during the breeding season. Ecology and Evolution 10.1002/ece3.511.

Heath, J.A., K. Steenhof, and M.A. Foster.  2012.  Shorter migration distances associated with higher winter temperatures suggest a mechanism for advancing nesting phenology of American Kestrels.  Journal of Avian Biology 43:376-384

Heath, J.A., E.H. Strasser, M.A. Foster, L. Bardo, and D.M. Bird.  2011.  Challenges in creating an American Kestrel body condition index based on size-adjusted mass.  Journal of Raptor Research 45:324-334.

Strasser, E.H. and J.A. Heath. 2011.  Effects of developmental conditions on nestling American Kestrel (Falco sparverius) corticosterone concentrations. General and Comparative Endocrinology 173:164-170. (ScholarWorks pdf)

Doherty, P.J. and J.A. Heath.  2011.  Factors affecting Piping Plover hatching success on Long Island, New York.  Journal of Wildlife Management 75:109-115.

McIntyre, A.F., and J.A. Heath. 2011. Evaluating the effects of foraging habitat restoration on shorebird reproduction: the importance of performance criteria and comparative design. Journal of Coastal Conservation 15:151-157.

Leonard, D.L., Jr. and J.A. Heath. 2010.  Foraging strategies are related to skull morphology and life history traits of Melanerpes woodpeckers. Journal of Ornithology 151:771-777.

McIntyre, A.F., J.A. Heath, and J. Jannsen. 2010. Trends in Piping Plover reproduction at Jones Beach State Park, NY, 1995-2007. Northeastern Naturalist17:493-504.

Steenhof, K. and J.A. Heath. 2009.  American Kestrel reproduction:  evidence for the selection hypothesis and the role of dispersal.  Ibis: 151:493-501. (Open American Kestral Reproduction – ScholarWorks pdf)

Heath, J.A. and E.G. Nolte.  2009.  Detectability of migrating raptors at Lucky Peak, Idaho.  Hawk Migration Studies XXXIV:16-17.

Heath, J.A., P.C. Frederick, J.A. Kushlan and K.L. Bildstein. 2009. White Ibis (Eudocimus albus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: doi:10.2173/bna.9

Heath, J.A., and P.C. Frederick.  2006. White Ibis integument color during the breeding season.  Journal of Field Ornithology 77:141-150. doi: 10.1111/j.1557-9263.2006.00034.x

Frederick, P.C., J.A. Heath, R.E. Bennetts, and H. Hafner.  2006. Estimating nests not present at the time of breeding surveys: an important consideration in assessing nesting populations.  Journal of Field Ornithology 77:212-219.

Heath, J.A., and P.C. Frederick.  2005.  Relationships among mercury concentrations, hormones, and nesting effort of White Ibises in the Florida Everglades.  Auk 122:255-267.

Frederick, P.C., B. Hylton, J.A. Heath, and M.G. Spalding.  2004.  Use of historical wading bird feather samples to discover the timing of mercury contamination in the Florida Everglades.  Environmental Toxicology and Chemistry 23:1474–1478.

Lott, C.A., T.D. Meehan, and J.A. Heath.  2003.  Estimating the latitudinal origins of migratory birds using hydrogen and sulfur isotopes in feathers: Influence of marine prey base.  Oecologia 134:505-510.

Heath, J.A., P.C. Frederick, T. Edwards, and L.J. Guillette Jr.  2003. Reproductive physiology of free-living White Ibises (Eudocimus albus) in the Florida Everglades.  General and Comparative Endocrinology 133:118-131.

Frederick, P.C., B. Hylton, J.A. Heath, and M. Ruane.  2003. Accuracy and variation in estimates of large numbers of nesting birds by individual observers: A controlled simulation.  Journal of Field Ornithology 74:281-287.

Heath, J.A., and P.C. Frederick.  2003.  Trapping White Ibises with Rocket Nets and Mist Nets in the Everglades.  Journal of Field Ornithology 74:187-192.

Epanchin, P.N., J.A. Heath, and P.C. Frederick.  2002.  Effects of fires on foraging and breeding wading birds in the Everglades.  Wilson Bulletin 114:139-141.

Heath, J.A., and A.M. Dufty Jr.  1998.  Relationship between body condition and adrenal stress response in captive, juvenile American kestrels.  Physiological Zoology 71:67-73.

Heath, J.  1997.  Corticosterone levels of American kestrels during nest departure.Condor 99:806-811. (Open Corticosterone levels of American Kestrels – ScholarWorks pdf)


The Peregrine Fund’s American Kestrel Partnership
UCLA Genoscape Project
St. Mary’s University
HawkWatch International
Idaho State University


We are thankful for support from:

  • The National Science Foundation
  • The US Fish and Wildlife Service
  • The Bureau of Land Management
  • The Strategic Environmental Research and Development Program (SERDP) of DoD, DoE, and EPA.
  • Osher Lifelong Learning
  • Adopt-a-box supporters
  • Idaho EPSCoR
  • Hycroft Mining Corporation
  • Idaho Army National Guard