The Influence of Migration Timing and Local Conditions on Reproductive Timing in Arctic-Breeding Birds.

Area of Science:

• Avian ecology
• Animal migration
• Arctic biology

Background:

• Nest initiation timing in Arctic-breeding shorebirds is crucial for reproductive success.
• Both local breeding conditions and non-breeding season events influence breeding timing.

Purpose of the Study:

• To investigate the relative importance of local conditions versus prior migration conditions on the timing of nest initiation in Arctic-breeding shorebirds.
• To understand how migration timing and speed affect breeding phenology.

Main Methods:

• Utilized tracking and breeding data from 248 individuals across 8 shorebird species/subspecies.
• Employed path analysis to model the relationships between snowmelt phenology, migration timing/speed, arrival timing, and nest initiation timing.

Main Results:

• Local conditions (snowmelt) and prior conditions (arrival timing) had similar, significant effects on nest initiation timing.
• Migration duration, not departure timing, was linked to later arrival and nesting.
• Longer migration distances correlated with later nesting.

Conclusions:

• Both local and prior conditions are critical drivers of breeding timing in Arctic shorebirds.
• Migration strategies and challenges significantly impact reproductive phenology.
• A full annual cycle perspective is essential for understanding and conserving Arctic-breeding bird populations.