Springing forward: Migrating songbirds catch up with the start of spring in North America.

Autor: Nemes CE; University of Maryland Center for Environmental Science, Appalachian Laboratory, Frostburg, Maryland, USA., Marra PP; The Earth Commons Institute; Department of Biology, McCourt School of Public Policy, Georgetown University, Washington, District of Columbia, USA., Zenzal TJ Jr; U.S. Geological Survey, Wetland and Aquatic Research Center, Lafayette, Louisiana, USA., Collins SA; Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, Louisiana, USA., Dossman BC; Department of Natural Resources and the Environment, Cornell University, Ithaca, New York, USA., Gerson AR; Department of Biology, University of Massachusetts, Amherst, Massachusetts, USA., Gómez C; SELVA: Investigación para la Conservación en el Neotrópico, Bogotá, Colombia., González AM; SELVA: Investigación para la Conservación en el Neotrópico, Bogotá, Colombia.; Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada., Gutierrez Ramirez M; Department of Biology, University of Massachusetts, Amherst, Massachusetts, USA.; Organismic and Evolutionary Biology Program, University of Massachusetts Amherst, Amherst, Massachusetts, USA., Hamer SA; Schubot Center for Avian Health, Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas, USA., Marty J; Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, Louisiana, USA., Vasseur PL; Louisiana Department of Wildlife and Fisheries, Rockefeller Wildlife Refuge, Grand Chenier, Louisiana, USA., Cohen EB; University of Maryland Center for Environmental Science, Appalachian Laboratory, Frostburg, Maryland, USA.
Jazyk: angličtina
Zdroj: The Journal of animal ecology [J Anim Ecol] 2024 Mar; Vol. 93 (3), pp. 294-306. Date of Electronic Publication: 2023 Nov 16.
DOI: 10.1111/1365-2656.14025
Abstrakt: In temperate regions, the annual pattern of spring onset can be envisioned as a 'green wave' of emerging vegetation that moves across continents from low to high latitudes, signifying increasing food availability for consumers. Many herbivorous migrants 'surf' such resource waves, timing their movements to exploit peak vegetation resources in early spring. Although less well studied at the individual level, secondary consumers such as insectivorous songbirds can track vegetation phenology during migration as well. We hypothesized that four species of ground-foraging songbirds in eastern North America-two warblers and two thrushes-time their spring migrations to coincide with later phases of vegetation phenology, corresponding to increased arthropod prey, and predicted they would match their migration rate to the green wave but trail behind it rather than surfing its leading edge. We further hypothesized that the rate at which spring onset progresses across the continent influences bird migration rates, such that individuals adjust migration timing within North America to phenological conditions they experience en route. To test our hypotheses, we used a continent-wide automated radio telemetry network to track individual songbirds on spring migration between the U.S. Gulf Coast region and northern locations closer to their breeding grounds. We measured vegetation phenology using two metrics of spring onset, the spring index first leaf date and the normalized difference vegetation index (NDVI), then calculated the rate and timing of spring onset relative to bird detections. All individuals arrived in the southeastern United States well after local spring onset. Counter to our expectations, we found that songbirds exhibited a 'catching up' pattern: Individuals migrated faster than the green wave of spring onset, effectively closing in on the start of spring as they approached breeding areas. While surfing of resource waves is a well-documented migration strategy for herbivorous waterfowl and ungulates, individual songbirds in our study migrated faster than the green wave and increasingly caught up to its leading edge en route. Consequently, songbirds experience a range of vegetation phenophases while migrating through North America, suggesting flexibility in their capacity to exploit variable resources in spring.
(© 2023 The Authors. Journal of Animal Ecology © 2023 British Ecological Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)
Databáze: MEDLINE
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