Hull Lab University of California, Davis

Migration Ecology of Golden-crowned Sparrows

Project Lead: Autumn Iverson

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Seventy percent of temperate-zone migrating songbirds have shown widespread decline in western North America over the last few decades. Along migration routes, songbirds face many threats such as navigational challenges, a changing predator assemblage, and shifting resources. They also face human related threats such as habitat loss and land-use changes. Due to the speed of these landscape changes, it is thought that songbirds are unlikely to evolve genetic adaptations that can keep pace.  Most research on migratory birds has occurred during the breeding season and migration is the least understood life history stage. Therefore, delineating migration paths as well as habitat quality and threats along those paths are critical research needs, especially on wide landscape scales. 

 

For seasonal passerine migrants, understanding how important the limiting factors experienced during migration are to the full life-cycle requires knowledge on different fronts, including how populations are connected between breeding and wintering ranges, how they utilize and choose stopovers during migration, and how climate changes in disparate home ranges may be affecting population numbers.

 

Golden-crowned Sparrows (Zonotrichia atricapilla; GCSP) breed in northern latitudes of North America such as Alaska, British Columbia and the Yukon, and winter along the west coast from British Columbia south to Baja California. The GCSP is considered a long-distance migrant with the entire population migrating seasonally between these locations. Although GCSP populations are not currently considered at risk, there is some indication that the species may be experiencing range shifts due to climate change.

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This research will investigate migration in a temperate-zone migrating songbird, the Golden-crowned Sparrow, by estimating migratory connectivity across the wintering range using stable isotope analysis, determining drivers for stopover locations using new miniaturized GPS technology, and investigating the effects of climate on annual population trends using Christmas Bird Count data.

 

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