Breeding success and adult survival of Redshank Tringa totanus on coastal meadows in SE Sweden
Förlag: NEDERLANDSE ORNITHOLOGISCHE UNIE
Breeding success and adult survival of Redshank Tringa totanus on coastal meadows on Gotland, SE Sweden, was investigated in 1997–2003. Two periods with different breeding success could be detected. In 1997–1999, nest success varied between 43 and 64%. Chick survival was not studied in these years. In 2000–03, nest success was lower and varied between 6 and 20%. Survival of chicks from hatching to fledging was estimated at 18%. Hence, overall productivity in 2000–03 was low and estimated to be only 0.13 fledglings per breeding pair. Nest survival rates were negatively related to incubation initiation date but fledging success was not related to hatching date. Adult survival rate was analysed from capture-resighting data of 164 adult Redshanks and was estimated at 80%. Adult survival did not differ significantly between sexes or between years. The results from this study suggest that reproductive success was lower than needed for a self-sustainable population, at least in the latter period with particularly low nest survival rates. There was no apparent change in management of meadows during the study period. Therefore, the decrease in nest survival rates was more likely to be an effect of changes in predator densities and/or behaviours. Further studies are needed to disentangle the mechanisms behind demographic processes in wader populations on coastal meadows.
- ISSN: 0373-2266