Elsevier

Animal Behaviour

Volume 137, March 2018, Pages 215-224
Animal Behaviour

Migratory hummingbirds make their own rules: the decision to resume migration along a barrier

https://doi.org/10.1016/j.anbehav.2018.01.019Get rights and content

Highlights

  • Migratory animals often need to traverse large ecological features en route.

  • We examine decisions of young hummingbirds departing from a coastal stopover site.

  • Young hummingbirds did not cross the Gulf of Mexico during autumn migration.

  • Young hummingbirds departed in the morning parallel with the coastline.

Knowing how naïve migrants respond to intrinsic and extrinsic factors experienced en route will allow a more thorough understanding of the endogenous migratory programme. To understand how inexperienced individuals respond to ecological features, we tracked the migratory departures of juvenile ruby-throated hummingbirds, Archilochus colubris, one of the smallest (∼ 3 g) and least-studied migrants, along the Gulf of Mexico during southbound migration using an international automated radiotelemetry system. The recent miniaturization of radiotags provides a novel method to track one of the smallest migratory birds, rendering the first information on departure decisions of known hummingbirds in relation to an ecological barrier. Using weather conditions and individual attributes, we also determined which factors influenced the time and direction of departure from a coastal stopover site. Most migrants (83%) departed in the morning, and daily departure time was only influenced by stopover duration, the amount of time spent at a stopover site. The majority (77%) of departure orientations paralleled the coastline, and we found little influence of any factor on departure direction. Our results reveal that (1) juvenile hummingbirds departing coastal Alabama move in a direction indicative of a circum-Gulf path during southbound migration and (2) departure decisions support a fly-and-forage strategy in which hummingbirds likely take advantage of resources along the coast while moving towards their destination.

Section snippets

Study Site and Capture Methods

Ruby-throated hummingbirds were captured at a long-term migration station (30°10′N, 88°00′W; Fig. 1) on the Bon Secour National Wildlife Refuge (NWR) in Fort Morgan, Alabama, U.S.A. The site was composed of scrub-shrub habitat and pine forest with Pinus elliottii, Quercus spp., Ilex spp., Smilax spp. and Serenoa repens as the dominant species (for a complete description see Zenzal, Fish, Jones, Ospina, & Moore, 2013). Autumn migrants that stopover at this site are immediately confronted with a

Departure Time

Most hummingbirds (83%, N = 43) departed Fort Morgan between sunrise and noon (mean: 0915 hours CDT, r = 0.80, P < 0.001; Fig. 2). The best supported candidate model contained stopover duration and departure day (ΔAICc = 0.00, AICc weight = 0.25; Table 2), although departure time did not appear to be influenced by departure day (coefficient = −0.03, SE = 0.03). Over half the individuals with departures between sunrise and noon tended to spend the night at the study site before departing (mean: 33.19 ± 45.6 h,

Discussion

A variety of factors are purported to influence the departure time (Müller et al., 2016) and direction (e.g. Deppe et al., 2015) of migrating animals, with foraging ecology and atmospheric conditions the likely primary selective forces on the endogenous migratory programme (Kerlinger & Moore, 1989). In our study, young hummingbirds generally departed from the Fort Morgan Peninsula in the morning, consistent with observations of migrating hummingbirds in the northeastern United States (Hall &

Acknowledgments

We thank the 2011–2014 Fort Morgan banding station field technicians, M. Tabasco and W. Santamaria for assistance in the Yucatan Peninsula, R. Bolus, L. Schofield, E. Swenson, A. Celis-Murillo, W. Cochran and J. Cochran for assistance with telemetry aspects of the project, J. Schaefer and C. Qualls for statistical advice, the 2011–2015 radio tower crews, as well as members of the Migratory Bird Research Group for their support. We also thank the Bon Secour National Wildlife Refuge, Fort Morgan

References (90)

  • K.P. Able

    The effects of overcast skies on the orientation of free-flying nocturnal migrants

  • K.P. Able et al.

    The development of orientation and navigation behavior in birds

    Quarterly Review of Biology

    (1987)
  • C. Agostinelli et al.

    R package ‘circular’: Circular statistics

    (2013)
  • S. Åkesson et al.

    Wind selectivity of migratory flight departures in birds

    Behavioral Ecolology and Sociobiology

    (2000)
  • S. Åkesson et al.

    Migration routes and strategies in a highly aerial migrant, the common swift Apus apus, revealed by light-level geolocators

    PLoS One

    (2012)
  • T. Alerstam

    Wind as a selective agent in bird migration

    Ornis Scandinavica

    (1979)
  • T. Alerstam

    Ecological causes and consequences of bird orientation

    Experientia

    (1990)
  • R.I. Bertin

    The ruby-throated hummingbird and its major food plants: Ranges, flowering phenology, and migration

    Canadian Journal of Zoology

    (1982)
  • H. Biebach et al.

    Strategies of passerine migration across the Mediterranean Sea and the Sahara Desert: A radar study

    Ibis

    (2000)
  • M.S. Bowlin

    Sex, wingtip shape, and wing-loading predict arrival date at a stopover site in the Swainson's thrush

    Auk

    (2007)
  • J.J. Buler et al.

    Migrant-habitat relationships during stopover along an ecological barrier: Extrinsic constraints and conservation implications

    Journal of Ornithology

    (2011)
  • K.P. Burnham et al.

    Model selection and multimodel inference: A practical information-theoretic approach

    (2002)
  • L.D. Caldwell et al.

    Comparison of fat levels in migrating birds killed at a central Michigan and a Florida Gulf coast television tower

    Wilson Bulletin

    (1963)
  • D.A. Cimprich et al.

    Energetic constraints and predation pressure during stopover

    Proceedings of the International Ornithological Congress

    (1999)
  • J.L. Deppe et al.

    Temporal patterns in fall migrant communities in Yucatan, Mexico

    Condor

    (2005)
  • J.L. Deppe et al.

    Fat, weather, and date affect migratory songbirds' departure decisions, routes, and time it takes to cross the Gulf of Mexico

    Proceedings of the National Academy of Sciences of the United States of America

    (2015)
  • B.C. Dossman et al.

    The effects of wind and fuel stores on stopover departure behavior across a migratory barrier

    Behavioral Ecology

    (2016)
  • A. Drake et al.

    Wind speed during migration influences the survival, timing of breeding, and productivity of a neotropical migrant, Setophaga petechia

    PLoS One

    (2014)
  • P. Feinsinger

    Ecological interactions between plants and hummingbirds in a successional tropical community

    Ecological Monographs

    (1978)
  • N.I. Fisher

    Statistical analysis of circular data

    (1993)
  • L. Galetto et al.

    Floral nectaries, nectar production dynamics, and chemical composition in six Ipomoea species (Convolvilaceae) in relation to pollinators

    Annals of Botany

    (2004)
  • R.E. Gill et al.

    Crossing the ultimate ecological barrier: Evidence for an 11000-km-long nonstop flight from Alaska to New Zealand and eastern Australia by bar-tailed godwits

    Condor

    (2005)
  • E. Gwinner et al.

    Endogenously controlled changes in migratory direction of the garden warbler, Sylvia borin

    Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology

    (1978)
  • G.A. Hall et al.

    The diurnal migration of passerines along an Appalachian ridge

    American Birds

    (1981)
  • A.J. Helbig

    Inheritance of migratory direction in a bird species: A cross-breeding experiment with SE- and SW-migrating blackcaps (Sylvia atricapilla)

    Behavioral Ecology and Sociobiology

    (1991)
  • C.W. Helms et al.

    Winter and migratory weight and fat field study on some North American bunting

    Bird-Banding

    (1960)
  • R.L. Hutto

    On the importance of en route periods to the conservation of migratory landbirds

    Studies in Avian Biology

    (2000)
  • P. Kerlinger et al.

    Atmospheric structure and avian migration

  • H. Kokko

    Competition for early arrival in migratory birds

    Journal of Animal Ecology

    (1999)
  • B. Kranstauber et al.

    Global aerial flyways allow efficient travelling

    Ecology Letters

    (2015)
  • C. Lara

    Temporal dynamics of flower use by hummingbirds in a highland temperate forest in Mexico

    Ecoscience

    (2006)
  • R.C. Lasiewski

    The energetics of migrating hummingbirds

    Condor

    (1962)
  • F. Liechti et al.

    The relevance of wind for optimal migration theory

    Journal of Avian Biology

    (1998)
  • Å. Lindström et al.

    A puzzling migratory detour: Are fueling conditions in Alaska driving the movement of juvenile sharp-tailed sandpipers?

    Condor

    (2011)
  • U. Lund et al.

    S-plus original by Ulric Lund and R port by Claudio Agostinellu. CircStats: Circular statistics, from “Topics in circular statistics” (2001)

    (2012)
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