Caitlin W. Robinson-Nilsen

The California Gull (Larus californicus) population in the South San Francisco Bay has increased from fewer to 200 breeding Gulls in 1982, to a peak of 52,172 in 2012. Specific to this study there were 46,030 breeding Gulls in 2010 and 37,716 breeding Gulls in 2011.

The Pacific Coast population of the Western Snowy Plover (Charadrius nivosus nivosus, Snowy Plover) breeds along or near tidal waters and is behaviorally distinct from the interior population (Funk 2007).

In 2011, we recorded Snowy Plover numbers, site use, nest success, fledging success, use of habitat enhancement project sites, species of nest predators and avian predator numbers throughout the Snowy Plover breeding season.

In 2010, we recorded Snowy Plover numbers, site use, nest success, fledging success, use of habitat enhancement project sites, species of nest predators and avian predator numbers throughout the Snowy Plover breeding season.

In San Francisco Bay, three former salt pond complexes (Alviso, Eden Landing, and Ravenswood) have been decommissioned, i.e., taken out of commission, and are planned for marsh restoration.

In order to determine where the displaced California Gulls would nest in 2011 and to prevent them from nesting in ecologically sensitive areas, the San Francisco Bay Bird Observatory (SFBBO) and the Don Edwards San Francisco Bay National Wildlife Refuge (Refuge) conducted intensive surveys and se

We have included a summary table of areas where gulls were re-sighted in 2011, the number seen in each area, if the gulls were adults or immature, and the months banded gulls were observed at that location.

Our objectives are to determine the impact of gulls on breeding snowy plovers and Forster’s terns.; Color-mark California gulls at A6 to determine potential nesting distributions after restoration of A6.; Continue our California gull colony surveys to document current population size.

This study addresses these questions: What is the flush rate and flush distance of nesting snowy plovers in response to new trail use around seasonally-dry ponds where birds nest? Do plovers respond differently to people who have disturbed them versus people they have not seen before?

We surveyed on 22 salt ponds in the Coyote Hills, Dumbarton, and Mowry salt pond complexes from October 2009 – November 2010. During the surveys, we recorded the number of birds, species and behaviors. We also recorded the birds’ locations within the ponds, using a 250m X 250m grid system.