Waterbird count includes rare winter sighting of Caspian tern

on February 1, 2017

Waterbird count includes rare winter sighting of Caspian tern

on February 1, 2017

ACR staff and volunteers conducted the second of four annual waterbird counts on Tomales Bay in mid-January. The team of 17, including 11 volunteers, launched from the Marshall Boat Works in three boats and made a complete sweep of the bay over the course of the chilly but clear morning.

Approximately 19,400 waterbirds were counted, which is low relative to past seasons when as many as 35,000 birds could be seen. Highlights included the sighting of three Caspian Terns, a common sight on Tomales Bay in summer, but rarely seen in winter, and at least one Black Scoter, a lovely bird that is thought to be in decline. Bufflehead and Greater Scaup were most numerous (counted about 6,300 Bufflehead and 6,400 Scaup), and although gulls are counted during the Christmas Bird Count, they are not included in the regular ACR waterbird surveys.

The ecological diversity of Tomales Bay provided for plenty of animated conversation between the boats: just north of Cypress Grove, radar revealed a wall of spawning Pacific herring and what looked like close to a hundred harbor seals on the surface mixed with Double-crested and Brandt’s Cormorants in a feeding frenzy; lunch break delivered an Osprey overhead carrying a perch; early afternoon included a Peregrine Falcon on Duck Island, two Bald Eagles on Hog Island, our friendly game warden watching for poachers, and perhaps the biggest birds of the day, five Air Force transporters making a very low-elevation test run up the coast. So much going on both above and below the surface!

ACR waterbird counts are coordinated by Emiko Condeso, ACR Ecologist / GIS specialist, and could not be done without the help of many dedicated volunteers, some of whom — like Tom Baty — have been working alongside the team since the inception of the counts in the early 1990s.

For detailed analysis of winter waterbird activity on Tomales Bay and the effects of spawning Pacific herring on their numbers, see the 2016 Ardeid, ACR’s Journal of Conservation Science and Stewardship. Supporter-level members receive a complimentary print edition of The Ardeid. Become a member today to receive your copy!