The Fall Crew arrived on Southeast Farallon Island on 16 August to find two adult Blue-footed Boobies, an adult Brown Booby, and the continuing adult Northern Gannet, all on Sugarloaf and right above where we conducted the switchover with the Seabird Crew. Three species of birds from the family Sulidae at one location in California is highly unusual, since none of these species breed in the state. Thankfully, this was to be an auspicious start to a bountiful August and September.
Over the past several years, the weather during late summer (Aug-Sep) has been mostly foggy or windy, with just occasional light winds and high overcast days that are conducive to allowing migrants to the find the island. This year, however, was quite the opposite, with fog noted for brief periods on only 7 days, and winds stronger than 10 knots on only 10 days, and never stronger than 20 knots.
The weather throughout early September was even more conducive to migration – high overcast skies and very light winds nearly every day – resulted in still greater numbers and more diversity. Yellow Warblers and Townsend’s Warblers were most abundant, especially compared to recent years, with 54 and 40 arrivals respectively. Highlights from this period included our 36th record of Green Heron, a flock of four White-faced Ibis (just the 3rd occurrence of this species at the Farallones), our 28th record of White-winged Dove, our 46th Chimney Swift, our 22nd and 23rd Acorn Woodpeckers, possibly our 4th Alder Flycatcher (DNA analysis will be required to separate it from eastern Willow Flycatcher - until then, it is considered a Traill's Flycatcher), our 11th Yellow-bellied Flycatcher, 69th Mourning Warbler, 77th Bay-breasted Warbler, 70th Prairie Warbler, and an adult male Indigo Bunting (rare plumage for fall). A short lull in bird migration occurred during mid-month. This may have been due to the excellent visibility, which allows birds to see the mainland, where food and shelter are more plentiful.