Free meals during breeding: increased resource access does not benefit Arctic-nesting shorebirds

Abstract

AO_SCPLOWBSTRACTC_SCPLOWArctic ecosystems are facing intensifying impacts of climate change, notably an increase in air temperature that can boost local productivity. Yet whether such resource surge can benefit declining migratory birds is unclear. Here we experimentally increased prey abundance and measure its effect on the body condition, nesting patterns, and nesting success of the white-rumped sandpiper (Calidris fuscicollis). We captured females at the beginning and at the end of their incubation to assess body condition and we installed small temperature probes inside their nests to measure their incubation recess. To estimate nest survival, we regularly monitored experimental and control nests during two consecutive summers (2016-2017). For both experimental years with contrasting nest success (73% vs. 21%), we found no evidence of an effect of our supplementation experiment mimicking an increased abundance of arthropods in the Canadian Arctic. This suggests that in situ resources are not limiting during incubation. Breeding strategies and success in shorebirds seem to be driven by inter-individual traits related to body condition upon the initiation of incubation.