Date: 5/16/25 3:48 pm From: Liam Murphy via groups.io <liammsf...> Subject: [SFBirds] Bernal Hill - Another Vagrant Report
Hi again SFBirders,
This message is to report that fellow Bernal birder Lyra D'Souza recorded a singing HOODED WARBLER this morning on the Hill, near the "three pines" area on the north slope. 37.743753,-122.413418
Earlier in the morning, prior to encountering the GRASSHOPPER SPARROW reported to the list in a separate message, I had seen a yellow-colored warbler in that area with a strange head pattern, dark olive crown and nape, and the appearance of an eyeline which I think included dark lores. I considered at the time that this could be an immature Hooded Warbler instead of the common Wilson's, and I watched for a while to try and see the white outer tail feathers that would be diagnostic. I never saw the undertail and the bird did not fan its tail, although it was quite active. After a minute or so of not seeing any white, I wrote it off as a weird Wilson's and moved on.
After reading more about Hooded Warblers on Birds Of The World, it seems that the formative plumages are sexually dimorphic and that males typically show a bolder pattern than what I saw (my description is a better fit for the female formative plumage). The text also says that the formative plumage is held from summer/fall of the hatch year until summer/fall of the following year. Furthermore, while females have been documented singing, this behavior is thought to be very rare.
Maybe someone on this list has additional insights into molt timing, plumage variability (how washed out can males be?), behavior including singing on migration, etc.
There's enough uncertainty in my observation for me to feel most comfortable leaving this at "new world warbler sp." on my checklist. From not carrying my camera, to not attempting cell phone pics, to not asking Lyra to listen to her recording when we spoke in the field, I pretty much botched most of the best practices of identification on this bird. Lyra's recording, however, is a slam dunk, congrats to her on a great find. After receiving the recording at lunchtime, I went back up to the spot and spent about 45 minutes there, without success.
Moral of the story, when in doubt, be a Lyra and not a Liam! Get that documentation by any means necessary (and don't leave your camera sitting on the bed at home).
It's not clear whether either of these vagrants from this morning have remained on the Hill, but hopefully someone can catch up to one or both of them at first light tomorrow (from 7:30-8am the hill belongs to the dog walkers).
