Seasonal survival and migratory connectivity of the Eurasian Oystercatcher revealed by citizen science

Resightings outside of The Netherlands for Eurasian Oystercatchers included in the current study. Resightings are color-coded according to the season they were observed: Spring = February, March; Summer = April, May, June; Autumn = July, August; Winter = September, October, November, December, January. Note that seasons are based on oystercatcher movements rather than weather-determined seasons. The geographical area (state) where the individual was ringed is denoted by the shape of the symbols. The top-left inset displays individuals resighted in northern Europe while the bottom-left inset displays individuals resighted in southwestern Europe.

Authors: Andrew M. Allen,1,2 Bruno J. Ens,2,3 Martijn van de Pol,2,4 Henk van der Jeugd,2,5 Magali Frauendorf,2,4 Kees Oosterbeek,2,3 and Eelke Jongejans1,2

Year: 2019

Publication: The Auk

Publication Link:

Full-text Access: Open

Affiliations: 1 Radboud University, Department of Animal Ecology and Physiology, Nijmegen, The Netherlands
2 Centre for Avian Population Studies, The Netherlands
3 Sovon Dutch Centre for Field Ornithology, Sovon-Texel, Den Burg, The Netherlands
4 Netherlands Institute of Ecology, Department of Animal Ecology NIOO_KNAW, Wageningen, The Netherlands
5 Dutch Centre for Avian Migration and Demography NIOO_KNAW, Wageningen, The Netherlands

Corresponding Author: Andrew M. Allen,

Funding: This research is supported by the Applied and Engineering Sciences domain, TTW, which is part of The Netherlands Organisation for Scientific Research (NWO), NWO-TTW grant 14638. The research was also cofunded by NAM, the Royal Netherlands Air Force, Birdlife Netherlands and Deltares.

Keywords: citizen science, migratory connectivity, multi-state, partial migration, program mark, seasonal survival

Abstract: Migratory connectivity describes linkages between breeding and non-breeding areas. An ongoing challenge is tracking avian species between breeding and non-breeding areas and hence estimating migratory connectivity and seasonal survival. Collaborative color-ringing projects between researchers and citizen scientists provide opportunities for tracking the annual movements of avian species. Our study describes seasonal survival and migratory connectivity using data from more than 4,600 individuals with over 51,000 observations, predominantly collected by citizen scientists. Our study focuses on the Eurasian Oystercatcher (Haematopus ostralegus), a species that has experienced a substantial and ongoing decline in recent decades. Multiple threats have been described, and given that these threats vary in space and time, there is an urgent need to estimate demographic rates at the appropriate spatio-temporal scale. We performed a seasonal multi-state (5 geographical areas within The Netherlands) live- and dead-recoveries analysis under varying model structures to account for biological and data complexity. Coastal breeding populations were largely sedentary, while inland breeding populations were migratory and the direction of migration varied among areas, which has not been described previously. Our results indicated that survival was lower during winter than summer and that survival was lower in inland areas compared with coastal areas. A concerning result was that seasonal survival of individuals over-wintering in the Wadden Sea, an internationally important site for over-wintering shorebirds, appeared to decline during the study period. We discuss the outcomes of our study, and how citizen science was integral for conducting this study. Our findings identify how the demographic rates of the oystercatcher vary in space and time, knowledge that is vital for generating hypotheses and prioritizing future research into the causes of decline.

Supplementary Material:

Intrusive Methodologies: 3,030 birds were fitted with coloured rings having been captured by mist nets, cannon nets, and traps on nest.

Citizen Science: Citizen scientists provided 51,001 observations of ringed birds

Conservation: “These findings highlight how an understanding of migratory connectivity can inform conservation of Dutch oystercatcher populations. Our findings are also important for generating hypotheses for future research about the contributions that spatio-temporally varying threats make towards the oystercatcher decline, such as the causes for low survival of inland breeding oystercatchers. A deeper understanding of the causes will be vital for developing conservation actions at the appropriate temporal and spatial scale (Marra et al. 2011, Hostetler et al. 2015).

Leave a Reply

Your email address will not be published. Required fields are marked *