Migration patterns of San Francisco Bay Area Hermit Thrushes differ across a fine spatial scale

Allison R. Nelson 1 , 2 , Renée L. Cormier 3 , Diana L. Humple 3 , Josh C. Scullen 2 , Ravinder Sehgal 1  and Nathaniel E. Seavy 3
  • 1 San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, U.S.A.
  • 2 San Francisco Bay Bird Observatory, 524 Valley Way, Milpitas, CA 95035, U.S.A.
  • 3 Point Blue Conservation Science, 3820 Cypress Drive #11, Petaluma, CA 94954, U.S.A.


Effective conservation of short-distance migrants requires an understanding of intraspecific variation in migratory patterns across small spatial scales. Until the advent of ultra-light geolocation devices, our knowledge of the migratory connectivity of songbirds was limited. For the Hermit Thrush (Catharus guttatus), subspecies delineations and connectivity patterns have been unclear in the portion of their breeding range in western North America from southeastern Alaska to northwestern Washington, where individuals wintering in the San Francisco Bay Area of California purportedly breed. To determine breeding locations and migratory timing of the Bay Area’s wintering Hermit Thrushes, we deployed geolocators at sites to the north and south of the San Francisco Bay. We compared results from these two regions to one another and to connectivity patterns suggested by subspecies definitions. We collected morphometrics to identify regional differences. Hermit Thrushes that wintered in the North Bay had a wider and more southerly breeding distribution from the British Columbia coast to northwestern Washington, whereas South Bay thrushes migrated to southeastern Alaska and the British Columbia coast. In general, North Bay thrushes departed wintering grounds and arrived on breeding grounds earlier than South Bay thrushes, but we cannot eliminate sex as a factor in these differences. Regional morphology differed only in bill length. Intraspecific isolation in glacial refugia during the Late Pleistocene may explain these fine-scale geographic variations in migration patterns and morphology.

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  • [1] Webster M.S., Marra P.P., Haig S.M., Bensch S., Holmes R.T., Links between worlds: unraveling migratory connectivity, Trends Ecol. Evol., 2002, 17, 76–83

  • [2] Boulet M., Norris D.R., Introduction: the past and present of migratory connectivity, Ornithol. Monogr., 2006, 61, 1–13

  • [3] Webster M.S., Marra P.P., in:, Greenberg R, Marra P.P. (Eds.), Birds of Two Worlds: The Ecology and Evolution of Migration, Johns Hopkins University Press, Baltimore, 2005

  • [4] Calvert A.M., Walde S.J., Taylor P.D., Nonbreeding-season drivers of population dynamics in seasonal migrants: conservation parallels across taxa, Avian Conserv. Ecol., 2009, http://www.ace-eco.org/vol4/iss2/art5/

  • [5] Ruegg K.C., Smith T.B., Not as the crow flies: a historical explanation for circuitous migration in Swainson’s Thrush (Catharus ustulatus), Proc. R. Soc. Lond. B Biol. Sci., 2002, 269, 1375–1381

  • [6] Voelker G., Bowie R.C.K., Klicka J., Gene trees, species trees and Earth history combine to shed light on the evolution of migration in a model avian system, Mol. Ecol., 2013, 22, 3333–3344

  • [7] Alvarado A.H., Fuller T.L., Smith T.B., Integrative tracking methods elucidate the evolutionary dynamics of a migratory divide, Ecol. Evol., 2014, 4, 3456–3469

  • [8] Faaborg J., Holmes R.T., Anders A.D., Bildstein K.L., Dugger K. M., Gauthreux, Jr. S. S., et al., Conserving migratory land birds in the New World: do we know enough?, Ecol. Appl., 2010, 20, 398–418

  • [9] Bearhop S., Fiedler W., Furness R.W., Votier S.C., Waldron S., Newton J., et al., Assortative mating as a mechanism for rapid evolution of a migratory divide, Science, 2005, 310, 502–504

  • [10] Berthold P., Helbig A.J., Mohr G., Querner U., Rapid microevolution of migratory behaviour in a wild bird species, Nature, 1992, 360, 668–670

  • [11] Jones J., Norris D.R., Girvan M.K., Barg J.J., Kyser T.K., Robertson R.R., Migratory connectivity and rate of population decline in a vulnerable songbird, Condor, 2008, 110, 538–544

  • [12] Phillips A.R., The Known Birds of North and Middle America: Part II, Allan R. Phillips, Denver, 1991

  • [13] Pyle P., Identification Guide to North American Birds: Part 1, Slate Creek Press, Bolinas, 1997

  • [14] Dellinger R., Wood P.B., Jones P.W., Donovan T.M., Hermit Thrush (Catharus guttatus), Birds North Am. Online, 2012, http://bna.birds.cornell.edu/bna/species/261

  • [15] Aldrich J.W., Population characteristics and nomenclature of the Hermit Thrush, Proc. United States Natl. Museum, Smithson. Inst., 1968, 124, 1–33

  • [16] Dickerman R.W., Parkes K.C., in:, The Era of Allan R. Phillips: A Festschrift, Horizon Communications Publishers, Albequerque, 1997

  • [17] Osgood W.H., New subspecies of North American birds, Auk, 1901, 18, 179–185

  • [18] Warner B.G., Mathewes R.W., Clague J.J., Ice-free conditions on the Queen Charlotte Islands, British Columbia, at the height of late Wisconsin glaciation, Science, 1982, 218, 675–677

  • [19] Greenberg R., Danner R., Olsen B., Luther D., High summer temperature explains bill size variation in salt marsh sparrows, Ecography (Cop.)., 2012, 35, 146–152

  • [20] Phillips A., Marshall J., Monson G., The Birds of Arizona, The University of Arizona Press, Tucson, 1964

  • [21] Storer R.W., Subspecies and the study of geographic variation, Auk, 1982, 99, 599–601

  • [22] Berthold P., Bird Migration: A General Survey, 2nd ed., Oxford University Press, Oxford, 1993

  • [23] McCabe T.T., McCabe E.B., Preliminary studies of western Hermit Thrushes, Condor, 1932, 34, 26–40

  • [24] McCabe T.T., McCabe E.B., From field and study: Hermit Thrushes of northwestern states, Condor, 1933, 35, 122–123

  • [25] Clement P., Thrushes, Princeton University Press, Princeton, 2000

  • [26] Stutchbury B.J.M., Tarof S.A., Done T., Gow E., Kramer P.M., Tautin J, et al., Tracking long-distance songbird migration by using geolocators, Science, 2009, 323, 896

  • [27] Bairlein F., Norris D.R., Nagel R., Bulte M., Voigt C.C., Fox J.W., et al., Cross-hemisphere migration of a 25g songbird, Biol. Lett., 2012, 8, 505–507

  • [28] Stach R., Jakobsson S., Kullberg C., Fransson T., Geolocators reveal three consecutive wintering areas in the thrush nightingale, Anim. Migr., 2013, 1, 1–7

  • [29] Rundel C.W., Wunder M.B., Alvarado A.H., Ruegg K.C., Harrigan R., Schuh A., et al., Novel statistical methods for integrating genetic and stable isotope data to infer individual-level migratory connectivity, Mol. Ecol., 2013, 22, 4163–4176

  • [30] Hobson K.A., Van Wilgenburg S.L., Faaborg J., Toms J.D., Rengifo C., Sosa A. L., et al., Connecting breeding and wintering grounds of Neotropical migrant songbirds using stable hydrogen isotopes: a call for an isotopic atlas of migratory connectivity, J. Field Ornithol., 2014, 85, 237–257

  • [31] Porzig E.L., Seavy N.E., Gardali T., Geupel G.R., Holyoak M., Eadie J. M., Habitat suitability through time: using time series and habitat models to understand changes in bird density, Ecosphere, 2014, 5, 1–16

  • [32] Samuels I.A., Gardali T., Humple D.L., Geupel G.R., Winter site fidelity and body condition of three riparian songbird species following a fire, West. N. Am. Nat., 2005, 65, 45–52

  • [33] Jaramillo A., Hudson S.E., Strong C.M., Coyote Creek Field Station Ten-Year Report, 1987-1996, San Francisco Bay Bird Observatory, Milpitas, 2003

  • [34] Ralph C.J., Geupel G.R., Pyle P., Martin T.E., Desante D.F., Handbook of Field Methods for Monitoring Landbirds, USDA Forest Service, Berkeley, 1993

  • [35] Lockwood R., Swaddle J.P., Rayner J.M.V, Avian wingtip shape reconsidered: wingtip shape indices and morphological adaptations to migration, J. Avian Biol., 1998, 29, 273–292

  • [36] Owen J.C., Collecting, processing, and storing avian blood: a review, J. Field Ornithol., 2011, 82, 339–354

  • [37] Griffiths R., Double M.C., Orr K., Dawson R.J.G., A DNA test to sex most birds, Mol. Ecol., 1998, 7, 1071–1075

  • [38] Lisovski S., Hahn S., GeoLight - processing and analysing light-based geolocator data in R, Methods Ecol. Evol., 2012, 3, 1055–1059

  • [39] Hill R.D., Braun M.J., In:, Sibert JR, Nielsen JL (Eds.), Electronic Tagging and Tracking in Marine Fisheries: Proceedings of the Symposium on Tagging and Tracking Marine Fish with Electronic Devices (7 - 11 Febr. 2000, Honolulu, Hawaii), University of Hawaii, Springer Netherlands, 2001, 315–330

  • [40] Worton B.J., Kernel methods for estimating the utilization distribution in home-range studies, Ecology, 1989, 70, 164–168

  • [41] Fudickar A.M., Wikelski M., Partecke J., Tracking migratory songbirds: accuracy of light-level loggers (geolocators) in forest habitats, Methods Ecol. Evol., 2012, 3, 47–52

  • [42] Ambrosini R., Møller A.P., Saino N., A quantitative measure of migratory connectivity, J. Theor. Biol., 2009, 257, 203–211

  • [43] Rodríguez-Ruiz J., de la Puente J., Parejo D., Valera F., Calero-Torralbo M.A., Reyes-González J.M., et al., Disentangling migratory routes and wintering grounds of Iberian near-threatened European Rollers Coracias garrulus, PLoS One, 2014, http://journals.plos.org/plosone/article?id=10.1371/ journal.pone.0115615

  • [44] Bell C.P., Leap-frog migration in the Fox Sparrow: minimizing the cost of spring migration, Condor, 1997, 99, 470–477

  • [45] Kelly J.F., Ruegg K.C., Smith T.B., Combining isotopic and genetic markers to identify breeding origins of migrant birds, Ecol. Appl., 2005, 15, 1487–1494

  • [46] Hallworth M.T., Marra P.P., Miniaturized GPS tags identify non-breeding territories of a small breeding migratory songbird, Sci. Rep., 2015, 5

  • [47] Baldwin M.W., Winkler H., Organ C.L., Helm B., Wing pointedness associated with migratory distance in commongarden and comparative studies of stonechats (Saxicola torquata), J. Evol. Biol., 2010, 23, 1050-1056

  • [48] Yong W., Moore F.R.., Flight, morphology, energetic condition, and the stopover biology of migrating thrushes, Auk, 1994, 111, 683–692

  • [49] Ketterson E.D., Nolan Jr. V., Geographic variation and its climatic correlates in the sex ratio of eastern-wintering Dark-eyed Juncos (Junco hyemalis hyemalis), Ecology, 1976, 57, 679–693

  • [50] Cristol D.A., Baker M.B., Carbone C., In: Nolan, Jr. V., Ketterson E.D., Thompson C. (Eds.), Current Ornithology, Kluwer Academic/Plenum Publishers, New York, 1999, 33-88

  • [51] Stouffer P.C., Dwyer G.M., Sex-biased winter distribution and timing of migration of Hermit Thrushes (Catharus guttatus) in eastern North America, Auk, 2003, 120, 836–847

  • [52] Bowlin M.S., Sex, wingtip shape, and wing-loading predict arrival date at a stopover site in the Swainson’s Thrush (Catharus ustulatus), Auk, 2007, 124, 1388–1396

  • [53] Delmore K.E., Fox J.W., Irwin, D.E., Dramatic intraspecific differences in migratory routes, stopover sites and wintering areas, revealed using light-level geolocators, Proc. Biol. Sci., 2012, 279, 4582–4589

  • [54] Delmore K.E., Irwin D.E., Hybrid songbirds employ intermediate routes in a migratory divide, Ecol. Lett., 2014, 17, 1211–1218

  • [55] Cormier R.L., Humple D.L., Gardali T., Seavy N.E., Light-level geolocators reveal strong migratory connectivity and withinwinter movements for a coastal California Swainson’s Thrush (Catharus ustulatus) population, Auk, 2013, 130, 283–290

  • [56] Ruegg K.C., Hijmans R.J., Moritz C., Climate change and the origin of migratory pathways in the Swainson’s thrush, Catharus ustulatus, J. Biogeogr., 2006, 33, 1172–1182

  • [57] Carrara P.E., Ager T.A., Baichtal J.F., Possible refugia in the Alexander Archipelago of southeastern Alaska during the late Wisconsin glaciation, Can. J. Earth Sci., 2007, 44, 229–244

  • [58] Shafer A.B.A., Cullingham C.I., Côté S.D., Coltman D.W., Of glaciers and refugia: a decade of study sheds new light on the phylogeography of northwestern North America. Mol. Ecol., 2010, 19, 4589–4621

  • [59] Swarth H.S., Origins of the fauna of the Sitkan District, Alaska, Proc. Calif. Acad. Sci., 1936, 23, 66–71

  • [60] Cook J.A., Dawson N.G., MacDonald S.O., Conservation of highly fragmented systems: the north temperate Alexander Archipelago, Biol. Conserv., 2006, 133, 1–15

  • [61] Topp C.M., Winker K., Genetic patterns of differentiation among five landbird species from the Queen Charlotte Islands, British Columbia, Auk, 2008, 125, 461–472

  • [62] Atwater B.F., Hedel C.W., Helley E.J., Late Quaternary depositional history, Holocene sea-level changes, and vertical crustal movement, southern San Francisco Bay, California, U.S.G.S. Professional Paper, 1977, 1014, 1–15

  • [63] Sillett T.S., Holmes R.T., Variation in survivorship of a migratory songbird throughout its annual cycle, J. Anim. Ecol., 2002, 71, 296–308

  • [64] Weir J.T., Schluter D., Ice sheets promote speciation in boreal birds, Proc. Biol. Sci., 2004, 271, 1881–1887

  • [65] Outlaw D.C., Voelker G., Mila B., Girman D.J., Evolution of long-distance migration in and historical biogeography of Catharus thrushes: a molecular phylogenetic approach, Auk, 2003, 120, 299–310

  • [66] Winker K., Pruett C.L., Seasonal migration, speciation, and morphological convergence in the genus Catharus (Turdidae), Auk, 2006, 123, 1052-1068

  • [67] Delmore K.E., Kenyon H.L., Germain R.R., Irwin D.E., Phenotypic divergence during speciation is inversely associated with differences in seasonal migration, Proc. R. Soc. B. Biol. Sci., 2015, 282, 20151921

  • [68] Ruegg K., Anderson E.C., Boone J., Pouls J., Smith T.B., A role for migration-linked genes and genomic islands in divergence of a songbird, Mol. Ecol., 2014, 23, 4757–4769

  • [69] Delmore K.E., Hübner S., Kane N.C., Schuster R., Andrew R.L., Câmara F., et al., Genomic analysis of a migratory divide reveals candidate genes for migration and implicates selective sweeps in generating islands of differentiation, Mol. Ecol., 2015, 24, 1873–1888

  • [70] Topp C.M., Pruett C.L., McCracken K.G., Winker K., How migratory thrushes conquered northern North America: a comparative phylogeography approach, PeerJ, 2013, https:// dx.doi.org/10.7717/peerj.206

  • [71] Norris R.D., Marra P.P., Seasonal interactions, habitat quality, and population dynamics in migratory birds, Condor, 2007, 109, 535–547

  • [72] Sauer J.R., Hines J.E., Fallon J.E., Pardieck K.L., Ziolkowski, Jr. D. J., Link W.A., The North American Breeding Bird Survey, Results and Analysis 1966 - 2013, Version 01.30.2015, USGS Patuxent Wildl. Res. Cent., 2015


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