Snowmelt and laying date shape the parental care strategy of a high-Arctic shorebird

Parental care varies across animal taxa, from uniparental to biparental care, driven by ecological and social factors such as weather, food availability, predation, and partner availability. Understanding this diversity within species can reveal biotic and abiotic conditions allowing uniparental versus biparental strategies. This study examines the impact of biotic and abiotic factors on parental care strategies in Sanderlings (Calidris alba), one of the few species that uses both types of care. Using long-term data from Greenland (2011-2023), path analyses revealed that laying date and snowmelt influence parental care strategies, with indirect climatic effects during migration and on breeding grounds. We observed a greater proportion of uniparental nests in years with delayed laying dates, and a greater proportion of biparental nests in years with delayed snowmelt. These findings underscore the complex interplay between environmental factors and parental care strategies, offering insights into how these strategies may evolve under changing ecological conditions.

Methods
The dataset comes from a long-term field study based in Greenland. Sanderlings' nests are equipped with thermologgers, i.e., TinyTag to record temperatures during the incubation. This allows to infer the parental care strategy, biparental or uniparental of each nest, laying date, abundance, and predation pressure. Climatic variables were extracted from different sources (meteorological stations, satelite...). We processed all data with R.