Intra-tropical movements as a beneficial strategy for Palearctic migratory birds

Abstract

Migratory birds often move significantly within their nonbreeding range before returning to breed. It remains unresolved under which circumstances individuals relocate, whether movement patterns are consistent between populations and to what degree the individuals benefit from the intra-tropical movement (ITM). We tracked adult great reed warblers Acrocephalus arundinaceus from a central and a southeastern European breeding population, which either stay at a single non-breeding site, or show ITM, i.e. move to a second site. We related ITM to the normalized difference vegetation index (NDVI) describing vegetation conditions and probably reflecting food abundance for these insectivorous birds. Three quarters of birds showed ITM across the non-breeding range. We found no difference in range values and mean values of NDVI between the single non-breeding sites of stationary birds and the two sites of moving birds. The vegetation conditions were better at the second sites compared to the first sites during the period which moving birds spent at the first sites. Vegetation conditions further deteriorated at the first sites during the period the moving birds resided at their second sites. Our study provides evidence that birds probably benefit from improved conditions after ITM compared to the conditions at the sites from where they departed.

• author: Koleček, Jaroslav ; Hahn, Steffen ; Emmenegger, Tamara and Procházka, Petr
• publishing date: 2018-01
• type: Contribution to journal
• publication status: published
• keywords: Geolocator, Habitat deterioration, NDVI, Passerines, Sub-Saharan Africa, Vegetation conditions
• in: Royal Society Open Science
• volume: 5
• issue: 1
• article number: 171675
• pages: 10 pages
• publisher: Royal Society Publishing
• external identifiers: scopus:85040064916
• ISSN: 2054-5703
• DOI: 10.1098/rsos.171675
• language: English
• LU publication?: no
• additional info: Funding Information: This study was supported by the GACR Czech Science Foundation (13-06451S) and through the Institutional Research Plan (RVO: 68081766) to J.K. and P.P. and by SNF Swiss National Science Foundation (grant no. 31003A_160265) to S.H. and T.E. Geolocator development was funded by the Swiss Federal Office for Environment (UTF nos 254, 332, 363, 400). Funding Information: Ethics. The study was carried out with permissions of regional conservation authorities (permit nos 00312/PA/2008/ AOPK and JMK20189/2010). Bird catching and ringing was conducted under licence (nos 906, 1023, 1050 and 1058) and followed rules issued by the Czech Bird Ringing Centre. The fieldwork adhered to the Animal Care Protocol of the Czech Academy of Sciences (nos 173/2008 and 128/2010) and was in compliance with current Czech Law on the Protection of Animals against Mistreatment (licence nos V/1/2005/28 and 0008/98-M103). Fieldwork in Bulgaria was permitted by the Bulgarian Ministry of Environment and Waters (no. 627/30.03.2015). Data accessibility. The data and codes underlying analyses are available as electronic supplementary material, S1–S3. Authors’ contributions. J.K. and P.P. conceived the first ideas. T.E. programmed the NDVI acquisition software. J.K. analysed the data and wrote the manuscript. All the authors collected the data, revised the manuscript and gave their final approval for publication. Competing interests. We have no competing interests. Funding. This study was supported by the Czech Science Foundation (13-06451S) and through the Institutional Research Plan (RVO: 68081766) to J.K. and P.P. and by Swiss National Science Foundation (grant no. 31003A_160265) to S.H. and T.E. Geolocator development was funded by the Swiss Federal Office for Environment (UTF nos 254, 332, 363, 400). Publisher Copyright: © 2018 The Authors.
• id: 7334dfc5-b90f-4e71-a9dc-7d0fcd2aab29
• date added to LUP: 2021-10-29 11:05:05
• date last changed: 2022-03-19 04:17:15