Los Farallones

Dispatches from Point Blue’s field station on the Farallon Islands National Wildlife Refuge

Farallon Spring Songbird Surprise!

Farallon Spring Songbird Surprise!
On April 30 and May 1, the island witnessed a wave of spring passerine migrants! While northwest winds are generally prevailing during spring, easterly winds brought this influx of birds from the mainland. Birds that are blown out to SEFI tend to concentrate in the island’s three trees, where they are easily found. Passerines often stay for a few days to rest and refuel before continuing on their long journeys to northern breeding grounds. If weather conditions are favorable, the birds then tend to leave at night to avoid being seen by predators. While we still spend most of our days focused on our long-term seabird studies, it was amazing to watch the trees buzzing with activity as passerines busily flitted about! 

We were fortunate to have seven Warbling Vireos visit! Although these birds seem drab, they have a beautiful song and were great fun to watch as they foraged.

We saw two Hermit Warblers, one of which suddenly arrived at the lighthouse. When passerines find the island, they sometimes target the highest elevation point before working their way down to the trees.
The bespectacled Cassin’s Vireo is quite beautiful, and we had a pair that was foraging in very plain view below the trees. It was exciting to see another variety of Cassin’s (along with our Cassin’s Auklet celebrities) on the island! 

The visiting Orange-crowned Warblers were very fond of our Lavatera bushes, where they were surely finding many insects among the blossoms. This species is very similar to the Tennessee Warbler, but the latter has lighter undertail feathers.

Wilson’s Warblers seem bright and cheery with their yellow plumage and black caps.

As is the case with so many warblers, the male Townsend’s Warbler is simply stunning!

This Nashville warbler has a bold white eyering, and the male often sports a red cap.

Yellow-rumped Warblers from both the Audubon’s (top photo) and myrtle (bottom photo) subspecies groups often visit the island. The Audubon’s warbler can be distinguished by its yellow throat and gray cheeks, while the adult myrtle warbler has a white throat and black mask.

Many Black-throated Gray Warblers were busily hopping about in the trees. This species can be easily identified by the small yellow dot in front of the eye and boldly marked black and white face.

 warbler sketches by Anna Stunkel

Here is our total list of passerines and hummingbirds that arrived during this two-day wave:

Anna’s Hummingbird- 1
Allen’s Hummingbird- 2
Hammond’s Flycatcher- 1
Pacific-slope Flycatcher- 2
Cassin’s Vireo- 2
Warbling Vireo- 7
Barn Swallow- 1
House Wren- 1
Ruby-crowned Kinglet- 4
Hermit Thrush- 3
Townsend’s Solitaire- 1
Tennessee Warbler- 1
Orange-crowned Warbler- 3
Nashville Warbler- 3
Audubon’s Warbler- 11
Myrtle Warbler- 5
Audubon’s Warbler x Myrtle Warbler Intergrade- 1
Black-throated Gray Warbler- 5
Townsend’s Warbler- 10
Hermit Warbler- 2
Wilson’s Warbler- 3
Western Tanager- 3
Chipping Sparrow- 1
White-throated Sparrow- 1
White-crowned Sparrow- 3
Golden-crowned Sparrow- 3
Black-headed Grosbeak- 9
Lazuli Bunting- 3
Brown-headed Cowbird- 4
Bullock’s Oriole- 5
American Goldfinch- 1
House Sparrow- 2

Since this passerine wave, we are continuing to have other migrant visitors during our recent calm weather.