2018 Season Highlights
During the 2018 breeding season (February-August), 67 dedicated SFBBO volunteers spent 912 hours monitoring a total of 62 potential waterbird colonies across 52 sites, 52 of which became active breeding colonies. We monitored 17 gull, tern and shorebird colonies and 35 heron, egret and cormorant colonies.
Figure 1. Map of 2018 Colonial Waterbird colonies and peak nest counts in San Francisco Bay, CA. Circle sizes indicate peak nest counts for our target species groups. Counts are based on observational methods, and do not include data collected during California Gull walkthroughs.
In 2018 our volunteers monitored:
47 American Avocet nests
10 Black Skimmer nest
20 Black-necked Stilt nests
23,384 California Gull nests
34 Caspian Tern nests
621 Forster's Tern nests
324 Black-crowned Night Heron nests
767 Double-crested Cormorant nests
142 Great Blue Heron nests
109 Great Egret nests
3 Green Heron nests
232 Snowy Egret nests
Photo by Tom Grey
California Gulls are the most abundant nesting waterbird in the South San Francisco Bay and SFBBO has been monitoring the growth of the breeding population since 1980. In 2018, SFBBO monitored 10 California Gull colonies via walkthrough surveys from May 9–15. These 10 colonies encompass all known South Bay breeding locations of this species.
Figure 3. Percentage of breeding California Gulls within each colony site, 1980-2018, South San Francisco Bay, CA. PAFCB = Palo Alto Flood Control Basin. Alviso A6 provided dry habitat suitable for nesting gulls until 2010 when the levees were breached and the site was opened to tidal action. Following the loss of Alviso A6 as suitable nesting habitat, gulls redistributed to other nesting sites in the South Bay.
Please reference our Annual Report for complete data and descriptions. For reports from this year and previous years, please visit https://www.sfbbo.org/colonial-waterbird-monitoring.html