Summary.  The goal of our field project was to investigate the long-term effects of environmental change on the breeding ecology of arctic-breeding shorebirds at Nome, Alaska.  Our three focal study species were Western Sandpipers, Semipalmated Sandpipers, and Red-necked Phalaropes.  The sandpipers are long-distance migrants that breed on arctic tundra but winter at coastal sites in central and South America.  Birds were captured in mistnets and at nests, and were uniquely marked with colored leg bands and engraved flags.  We collected demographic data on shorebird ecology, including timing of breeding, reproductive success, and annual survival rates.  We also collected data on environmental conditions, including climate, timing of emergence and abundance of invertebrate prey, numbers of lemmings, and sightings of foxes, jaegers and other predators.  Our investigation included long-term comparisons across two decades of environmental change between the 7-year periods of 1993-1999 and 2008-2014.  We were also able to make comparisons across a network of arctic field sites because our field site at Nome was 1 of 10 sites that investigated shorebirds with the same set of standardized field protocols as part of the Arctic Shorebird Demographic Network directed by the Manomet Center for Conservation Sciences.

Intellectual merit.  Our project made four new contributions to arctic science.  First, we found that timing of nesting in sandpipers is not advancing but has been delayed by 3-7 days compared to birds breeding at the same site two decades ago.  Most investigations of reproductive timing in plants and animals have reported advances, but our arctic study is one of the few examples of delays in seasonal phenology.  Second, the main environmental factor affecting timing of egg-laying was spring temperatures during May, and all three species of shorebirds showed delays in breeding during cold springs.  Long-term climate data from Nome show evidence for warming trends in winter but unexpectedly a cooling trend in May during the breeding season of shorebirds.  Third, climate change led to phenological mismatches for arctic-breeding shorebirds.  We calculated mismatches between breeding shorebirds and their invertebrate prey at ten arctic sites for a three year period.  The strongest drivers of mismatch were daily temperatures during egg-laying, and the total amount of food available at an arctic site.  Last, we used new light-sensitive geolocator archival tags to collect the first data on migratory movements for shorebirds breeding in western Alaska.  We successfully deployed and recovered tags on small-bodied sandpipers that were <25 g in body mass.  Birds were captured and tagged at Nome, but migratory tracks showed that our single breeding population had a huge nonbreeding distribution ranging from southern Canada to Colombia in South America.

Broader impacts. Our field project had a series of broader impacts.  All field work was conducted on private lands of the Sitnasauk Native Corporation who supported this project by allowing access to study plots for our long-term monitoring of breeding sandpipers.  The field project at Nome was a collaboration between investigators at Kansas State University and Simon Fraser University in Canada.  We also participated in the Arctic Shorebirds Demographics Network which includes arctic sites in Russia, Alaska, and Canada.  Project activities at Nome provided training opportunities for two postdoctoral fellows, two graduate students, and seven research technicians.  Research products have included two peer-reviewed articles, two graduate dissertations and theses, and 12 conference presentations.  Public outreach included public presentations...

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