Non-breeding conditions induce carry-over effects on survival of migratory birds

Nathan W Cooper; Scott W Yanco; Clark S Rushing; T Scott Sillett; Peter P Marra

doi:10.1016/j.cub.2024.09.015

Non-breeding conditions induce carry-over effects on survival of migratory birds

Curr Biol. 2024 Nov 4;34(21):5097-5103.e3. doi: 10.1016/j.cub.2024.09.015. Epub 2024 Oct 4.

Authors

Nathan W Cooper¹, Scott W Yanco², Clark S Rushing³, T Scott Sillett⁴, Peter P Marra⁵

Affiliations

¹ Migratory Bird Center, Smithsonian's National Zoo and Conservation Biology Institute, Washington, DC 20008, USA. Electronic address: coopern@si.edu.
² School for Environment and Sustainability, University of Michigan, Ann Arbor, MI 48109, USA; Center for Biodiversity and Global Change, Yale University, New Haven, CT 06511, USA; Department of Integrative Biology, University of Colorado Denver, Denver, CO 80204, USA.
³ Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602, USA.
⁴ Migratory Bird Center, Smithsonian's National Zoo and Conservation Biology Institute, Washington, DC 20008, USA.
⁵ The Earth Commons Institute, Department of Biology, McCourt School of Public Policy, Georgetown University, Washington, DC 20057, USA.

PMID: 39368470
DOI: 10.1016/j.cub.2024.09.015

Abstract

Identifying the processes that limit populations is a foundational objective of ecology and an urgent need for conservation. For migratory animals, researchers must study individuals throughout their annual cycles to determine how environmental conditions limit demographic rates within each period of the annual cycle and also between periods through carry-over effects and seasonal interactions.¹^,²^,³^,⁴^,⁵^,⁶ Our poor understanding of the rates and causes of avian migration mortality⁷ hinders the identification of limiting factors and the reversal of widespread avian population declines.⁸^,⁹ Here, we implement new methods to estimate apparent survival (hereafter survival) during migration directly from automated telemetry data¹⁰ in Kirtland's Warblers (Setophaga kirtlandii) and indirectly from mark-recapture data in Black-throated Blue Warblers (S. caerulescens). Previous experimental and observational studies of our focal species and other migratory songbirds have shown strong effects of Caribbean precipitation and habitat quality on food availability,¹¹^,¹²^,¹³^,¹⁴ body condition,¹²^,¹³^,¹⁴^,¹⁵^,¹⁶^,¹⁷^,¹⁸^,¹⁹ migration timing,¹¹^,¹²^,¹⁵^,¹⁶^,²⁰^,²¹^,²²^,²³ natal dispersal,²⁴^,²⁵ range dynamics,²⁶ reproductive success,²⁰^,²²^,²⁷ and annual survival.¹⁸^,¹⁹^,²⁰^,²³^,²⁸^,²⁹^,³⁰^,³¹ Building on this research, we test the hypotheses that environmental conditions during the non-breeding period affect subsequent survival during spring migration and breeding. We found that reduced precipitation and environmental productivity in the non-breeding period strongly influenced survival in both species, primarily by reducing survival during spring migration. Our results indicate that climate-driven environmental conditions can carry over to affect survival in subsequent periods and thus likely play an important role in year-round population dynamics. These lethal carry-over effects may be widespread and are likely magnified by intensifying climate change.

Keywords: annual cycle; carry-over effect; climate change; environmental productivity; migration survival; migratory birds; precipitation; seasonal interaction; seasonal survival.

Published by Elsevier Inc.

MeSH terms

Animal Migration*
Animals
Climate Change
Ecosystem
Population Dynamics
Seasons
Songbirds* / physiology