This is really interesting and would appear to be extremely early.
In Birds of North America, Chestnut-backed Chickadee nesting dates are
reported as follows:
"Egg dates for California March 12 - June 7. Height of season April 7 -
" In California at Tilden Park, Contra Costa Co., mean date of first egg
for P.r.barlowi over a 22 year period (n=430) March 25 +- 9 days."
Subject: [EBB Sightings] Chestnut-backed Chickadee nesting
I installed a nestcam box on Jan 1 under the eaves of my house.
Chestnut-backed Chickadees started checking it out on Jan 13, and nest
construction started Feb 25. I put wood chips in the box, which were
quickly cleaned out on 2/25, then redwood bark shreds were brought in, and a
circular shape was constructed. I first saw 2 birds at once in the box on
Feb 27. It was slow going until today, March 8, with construction full
speed ahead. With the camera I am watching and hearing them on TV. Other
materials include feathers and dog hair. I will post progress.
Also, on my bike ride today Orange-crowned Warblers were singing along
Redwood Road, south of Pinehurst Road, the first ones I've heard this
Spring. I have not yet detected an Allen's Hummingbird in my yard. They
are usually here in late January or early February. There was a Rufous
Hummingbird yesterday at my feeder. Where's the Allen's?
There was a Yellow-rumped Warbler in my yard on Jan 2, the first in my yard,
I've been here in the Oakland hills for 19 years. That was yard species
Oakland, near Skyline and Shepherd Canyon