Updated Apr. 5, 2011 with partners list.

Researchers and seasoned birders, the Don Edwards National Wildlife Refuge, the San Francisco Bay Bird Observatory and USGS need your help this year in tracking the California gull (Larus californicus) as part of the South Bay Salt Pond Restoration Project.

Although a native of California, this gull species has left an interesting history in its wake. Normally breeding in inland areas like Mono Lake, "CAGU's" suddenly began appearing in the San Francisco Bay area in dramatic numbers over recent decades, from less than 200 prior to 1982 to over 45,000 counted in 2008.

According to USGS Western Ecological Research Center lead scientist Josh Ackerman, these gulls may have been attracted to the region because of its nearby landfills. But other than food scraps, CAGU's have also been voracious predators of other nesting waterbirds in the area, raiding the eggs and chicks of American avocets and black-necked stilts.

Some 20,000 CAGU's have been nesting each year in Tract A6 of the south San Francisco Bay restoration project -- the massive multiagency effort that's restoring acres of formerly private land back to natural wetlands. But in December 2010, Tract A6 was restored as a tidal marsh -- no longer a static, drying field, but instead a dynamic marsh with the daily ebb and flow of the bay tides.

So where will 20,000 voracious gulls now head to this year to establish new colonies? Researchers need your help to find out.

Caitlin Robinson-Nilsen of the San Francisco Bay Bird Observatory (SFBBO) is collecting the sighting data, which will contribute to research by Ackerman and managers at Don Edwards National Wildlife Refuge.

Here's how to participate:

• Detailed instructions and contact information are in this PDF flyer and this PDF flyer.
• Since 2008, SFBBO and USGS have banded over 1,000 CAGU's from A6 with 3-digit alphanumeric bands on the left leg (see above photo). Reporting the band number will greatly help the effort.
• Observers are encouraged to expand beyond the SF Bay area to coastal and Central Valley sites, particularly noting where CAGU's have not nested before.

It's collaborative science at its best, and your observations can help researchers understand the distribution and movement of a key species -- as well as the effects and implications of an ecosystem restoration project.

-- Ben Young Landis

Top: California gulls from Tract A6 will have noticeable leg bands on them, as seen here. Image courtesy of L. Ellis.