Whinchat survival estimates across Europe: can excessive adult mortality explain population declines?

• Published in: Animal conservation Vol. 24; no. 1; pp. 15 - 25
• Main Authors: Fay, R., Schaub, M., Banik, M. V., Border, J. A., Henderson, I. G., Fahl, G., Feulner, J., Horch, P., Korner, F., Müller, M., Michel, V., Rebstock, H., Shitikov, D., Tome, D., Vögeli, M., Grüebler, M. U.
• Format: Journal Article
• Language: English
• Published: London Wiley Subscription Services, Inc 01.02.2021
• Subjects: adult survival; Afro‐Palaearctic migrant; Agricultural land; Breeding; Breeding sites; Breeding success; Capture-recapture studies; capture–recapture; Conservation; Distance; Environmental conditions; Environmental impact; Grasslands; Habitat changes; juvenile survival; Juveniles; Migratory species; Mortality; Population; Population decline; Populations; Saxicola rubetra; Sex differences; sex‐specific survival; Survival; Wildlife conservation; Europe
• ISSN: 1367-9430; 1469-1795
• DOI: 10.1111/acv.12594

European farmland birds show massive large‐scale population declines due to agricultural intensification. Long‐distance migrants are particularly affected as their populations appear to undergo larger declines than those of residents and short‐distance migrants, raising the question about the impact of non‐breeding environmental conditions and their potential impact on annual survival. The whinchat Saxicola rubetra, an Afro‐Palaearctic migrant inhabiting open habitats, has strongly declined over the last decades. Most of the conservation effort for this species has focused on improving the breeding success in Europe, but it remains unclear whether habitat changes in non‐breeding areas may also have contributed to the population declines through a decrease in adult survival. We studied survival of whinchats from eight breeding populations across Europe by analysing capture–recapture data. We found that apparent survival was consistently higher in males than in females and higher in successful than in failed breeders independently of the sex. True adult survival may, however, hardly differ between sexes being about 0.5 and 0.6 and a simple population model suggests true juvenile survival to be between 0.2 and 0.35. Adult survival was unrelated to population trends suggesting that the main demographic problem of the whinchats is likely insufficient reproduction, a feature that is shared with other declining grassland specialists. Finally, in line with results on other migratory farmland species, our study suggests that conservation activities for whinchats should in first place focus on Europe. Abbreviated summary for graphical TOC: We analysed capture‐recapture data of whinchats originating from eight breeding populations across Europe to investigate survival rates. This multi‐population comparison allows testing for the consistency of age, sex and breeding success in survival estimates. Adult survival was unrelated to population trends suggesting that the main demographic problem of the whinchats is likely insufficient reproduction, a feature that is shared with other declining grassland specialists.