Global analysis of annual survival among shorebirds reveals a negative effect of migration distance and a decline in recent decades

Annual survival is a key demographic parameter driving population trends in wildlife populations. However, despite numerous species-specific or regional studies, global reviews of the factors affecting the survival of declining taxa remain scarce. Here, we investigated annual survival of fledged immature and adult shorebirds, a globally-distributed and substantially-declining avian taxon exhibiting diverse life-history and migration strategies. We compiled 796 estimates of annual survival from 436 populations of 105 species, spanning 133 years from 1891–2023. Next, we investigated temporal and spatial trends and the impact of different life-history traits on survival in a phylogenetic and spatial framework on a robust subset of 418 estimates from 1980 to the present. As expected, annual survival of adults was higher than immatures, and increased with body mass. Survival declined with longer migration distance, and marginally with breeding latitude. Additionally, annual survival significantly declined since 1980, especially among adult shorebirds. In contrast to previous analyses, neither insularity nor flyway type affected annual survival, and with small differences among continents. We concluded that annual survival did not show clear spatial patterns, but has declined substantially over recent decades. Some characteristics, including migratory behaviour, might make some populations of shorebirds more vulnerable than others. However, poor data coverage in some regions and methodological limitations might still mask local temporal and spatial patterns in the survival rates. The continuing collection of standardised data for population-specific demographic parameters of wild animals is essential for a better understanding of their population dynamics, as well as for the improvement of conservation strategies.