Long-billed Dowitcher Migration Ecology

Dowitchers 1Figure 1: Long-billed Dowitcher with coded transmitter (NTQB-4-2)

Understanding stopover strategies and migratory connectivity for habitat conservation

Background

Migratory shorebirds rely on a network of wetlands spread across large landscapes during their annual cycle. During migration, shorebirds will stopover at specific wetland complexes for different purposes and lengths of time. Understanding stopover strategies at these complexes, and pathways between stopovers and wintering areas, are imperative to inform effective habitat management and conservation strategies. This is especially true for shorebirds that use inland migratory routes where water is a finite resource and often highly managed.


Point Blue scientists captured 81 Long-billed Dowitchers (Limnodromus scolopaceus) during August-September 2012 and 2013 in the Klamath Basin, a migratory stopover along the Oregon-California border. They assessed flight feather molt status and attached VHF radio-tags (Lotek coded nanotags) to determine (1) their length of stay in the region and (2) winter destinations in California’s Central Valley.

Telemetry Device

• Model: NTQB-4-2
• Weight: ~1.2 g
• 153 day lifespan with five second burst interval
• Up to 521 transmitters on one frequency
• Retain ability to identify individuals
• Works with Lotek SRX receivers

The coded nanotags transmitted on a single VHF frequency, which allowed simultaneous monitoring of all birds present within entire regions of the Klamath Basin and Central Valley using aerial surveys. Location data was gathered during both migration and winter.

 

Preliminary Results

1) Average stopover duration after capture was 32 days in the Klamath Basin.
2) Nearly 60% of dowitchers marked in the Klamath Basin spent the winter in the Central Valley.
Most dowitchers were actively molting flight feathers when captured and had unusually long stopover durations compared to other published studies. These data suggest the Klamath Basin is an important staging area where dowitchers undergo their full prebasic molt when all feathers are replaced. This is a phenomenon known as molt migration, which is a well-known aspect of waterfowl migration that is rare in shorebirds.

 

Dowitchers 2 Figure 2: Map of study area and potentially important migratory stopover sites.

 

Publication: Barbaree, B.A., M. E. Reiter, C. W. Hickey, and G. W. Page. In prep. Evidence of molt migration and migratory connectivity in Long-billed Dowitchers in the interior Pacific Flyway.

 

About Point Blue Conservation Science
Pont Blue Conservation Science, founded as Point Reyes Bird Observatory in 1965, works to conserve birds, other wildlife and ecosystems through innovative scientific research and outreach. Our 140 scientists, along with educators and restoration specialists, work to reduce the impacts of habitat loss, climate change and other environmental threats while promoting nature-based solutions for wildlife and people, on land and at sea. Visit Point Blue at www.pointblue.org.