Notes from the Station

Species: Wilson’s Warbler
Most recent capture date: 5/22/2022
Age: less than two months old

Notes: This frazzled-looking bird probably only left the nest in the last few days. Scroll back a few posts to see what adult Wilson’s Warblers look like – it’s rather different!

Species: Black Phoebe
Most recent capture date: 5/21/2022
Age: less than three months old

Notes: You can tell this is a young phoebe by the yellow gape at the corner of the mouth and the cinnamon-colored bars on the wing.

Species: Hutton’s Vireo
Most recent capture date: 5/11/2022
Age: less than two months old

Notes: Caught in the company of the female from the previous post was this fluffy baby! As far as we can tell from our records, this is the first time since at least the early 1980s that Hutton’s Vireos have bred at our study site.

Species: Hutton’s Vireo
Most recent capture date: 5/11/2022
Earliest capture date: 10/17/2020
Age: two years old
Sex: female

Notes: Hutton’s Vireos are regulars for us in the winter, but not in the breeding season. The timing alone makes this bird a surprise – but she was an even bigger surprise due to who she was with… (to be continued!)

Species: Orange-crowned Warbler
Most recent capture date: 5/11/2022
Age: at least one year old
Sex: Female

Notes: This individual is more gray than our usual Orange-crowned Warblers. She may be a different subspecies.

Species: Yellow Warbler
Most recent capture date: 5/11/2022
Age: one year old
Sex: male

Species: Song Sparrow
Most recent capture date: 5/11/2022
Age: less than six weeks old

Notes: This bird’s overall yellowish wash, yellow gape at the corners of the bill, and loose fluffy plumage are all clues that this is a brand-new 2022 edition Song Sparrow.

Species: Mourning Dove
Most recent capture date: 4/30/2022

Notes: Mourning Doves have some lovely blues, greens, and yellows in the bare skin around their eyes.

Species: Chestnut-backed Chickadee
Most recent capture date: 5/08/2022
Age: at least one year old

Notes: This bird has some unusual white feathers; the technical term for this is “leucistic”. Leucisticism can have a variety of causes. We see it especially in the chickadees at our Jasper Ridge site, and we know that in at least one case a bird was leucistic in one year but normally pigmented in the next, so we suspect this is affected by the conditions the bird experiences while growing the feathers.

Species: Orange-crowned Warbler
Most recent capture date: 5/08/2022
Age: less than six weeks old

Notes: Where adults generally look sleek and put-together, recent fledglings have a plumage that looks looser, fluffier, dirtier. These are feathers grown quickly and energetically cheaply, with a lower density of barbs, at a time of life when the bird needs to go from naked to feathered ASAP. Under these feathers there is still a surprising amount of naked skin; those patches will fill in with body plumage over the next few months.