Atlas Dispatch: Jan 1-7, 2026 Rewind

Atlas Dispatch
Written By

The California Bird Atlas is off to an incredible start! In the first week, 445 atlasers submitted 2,656 checklists to the project. Atlasers covered 831 blocks in 51 counties and recorded 628,723 individual birds! Atlasers applied breeding codes to 2,865 observations.

Some Atlas firsts:

And we're off! At least 15 species were confirmed breeding this week, all official California Bird Atlas firsts:

  1. Great Horned Owl – Reported occupying a nest (ON) by Bill Haas at Paso Robles Westside, San Luis Obispo County
  2. Red-tailed Hawk – Reported building a nest (NB) by Bill Haas at Paso Robles Westside, San Luis Obispo County
  3. Anna's Hummingbird – Reported occupying a nest (ON) by Patti Koger at San Elijo Lagoon--west, San Diego County

  4. Great Egret – Reported building a nest (NB) by Joni Ciarletta at Batiquitos Lagoon--Cholla Point, San Diego County
    “Carrying sticks as it flew across El Camino Real toward the lagoon.”
  5. Bald Eagle – Reported building a nest (NB) by Kiandra Mitchell at Irvine Lake, Orange County
    “Resident adult pair occasionally working on the nest, plus the continuing young bird on the north peninsula”
  6. Great Blue Heron – Reported carrying nesting material (CN) by Andrea C at Bolsa Chica Ecological Reserve, Orange County
  7. Pied-billed Grebe – Reported with recently fledged young (FL) by Dominik Mosur at Laguna Honda Reservoir, San Francisco County
  8. Allen's Hummingbird – Reported building a nest (NB) by Joni Ciarletta at La Costa Canyon Park, San Diego County
  9. Rock Pigeon – Reported carrying nesting material (CN) by Andrea C at Bolsa Chica Ecological Reserve, Orange County
    “At least 2 flying from under the wooden PCH bridge to the bushes near parking lot. Would pop out with sticks and fly back under bridge. Witnessed this happening several times, and once by two birds flying in with twigs simultaneously.”
  10. Osprey – Reported carrying nesting material (CN) by Carolyn Thiele at Imperial Beach Sports Park, San Diego County
  11. California Thrasher – Reported carrying nesting material (CN) by Kathy Aldern, Jane Mygatt at Mahr Reservoir, San Diego County
  12. Western Bluebird – Reported building a nest (NB) by Carter Gasiorowski at Baker West Neighborhood, Santa Clara County
    “Female making multiple trips bringing clumps of dry grass into the nest box where bluebirds have nested the past six years. Male also went into the box but didn’t seem to help out.”
  13. Brandt's Cormorant – Reported building a nest (NB) by Justyn Stahl at Point La Jolla--seawatch, San Diego County
    “~50 nests in various stages with birds bringing in fresh material, about half attended by a pair, a few very far along. Majority of birds just roosting.”
  14. Eurasian Collared-Dove – Reported building a nest (NB) by Lucas stephenson at El Centro--southeastern region, Imperial County
  15. Song Sparrow – Reported carrying nesting material (CN) by Kerry Ross at Famosa Slough, San Diego County
    “The SOSP was perched with the bill full of grass for nearly 45 seconds before it decided it was sage to move, presumably, towards the nest structure. ”

Reports from the field:

Want to share a sighting? Email us at info@californiabirdatlas.org!

  • Over 90% of checklists were marked “Complete for breeding codes.” This provides scientists with valuable information on the timing of breeding activity, even when none is observed! More info here.
  • eBird reviewer and USFWS biologist Justyn Stahl wrote in to summarize activity in San Diego County: "Hummingbirds seem to be leading the charge, with Anna's and Allen's documented carrying, building, or on nests. A few egret/herons are building. This California Thrasher was well ahead of schedule; Unitt (2004) says 'Like most sedentary chaparral birds, the California Thrasher begins laying typically in the third week of March, but occasionally it begins earlier.' I took the low hanging fruit and went to confirm the Brandt's Cormorants are busy building in La Jolla.”

Before you hit “Submit”:

A few common pitfalls we noticed this week. If you’ve made any of these mistakes, please don’t fret. It’s only week #1 and we’re all learning! Thank you again to Justyn Stahl for noting many of these:

    • ON (Occupied Nest) for Ospreys perched near or even on nests, but not incubating. Use N (Visiting nest site) instead. ON is for birds with active nests presumed to have eggs or young when you can’t see the contents. Wait until you see birds sitting in nests in an incubating position before using ON.
    • CF (Carrying Food) applied to corvids. CF is for birds carrying food for young, but ravens, crows, and jays all commonly carry and cache food for themselves.
  • Applying UN (Used Nest) to last year’s (pre-Atlas) nests, particularly for Bald Eagle, Red-tailed Hawk, Osprey, and cormorants. This code should only be applied to nests that were used during the current breeding season. Since very few birds have nested this year, it’s generally too early to be using UN. Nests from 6-12 months ago (last year’s breeding season) should not get this code. One acceptable use of UN this week was for a Scaly-breasted Munia nest observed by Chris McCreedy that was active in mid-December, but was empty at the start of January. Thanks to Chris for pointing out the need for clarification around this code!

You may find a reviewer contacting you about an observation of yours—take what they say to heart, provide additional information if you can, and then get back out to atlasing! Learning more about birds and their behaviors is one of the joys of this effort.

What else is new?

  • New map: the only place to see hotspot locations and block boundaries together was within eBird Mobile after starting a list. We posted aAtlas blocks & eBird hotspots map on the CBA website to offer this view in another place. It should help plan your next atlasing outing!
  • Breeding code clarification: we clarified the meaning of three breeding codes. For more please see ourbreeding codes definitions page.
    • M – Multiple (7+) Singing Birds should only be used if you observe 7+ birds within the block on a single day.
    • H – In Appropriate Habitat can be used at any time of year for resident species that often maintain territories year round (e.g. Wrentit, Oak Titmouse, Cactus Wren).
    • UN - Used Nest should only be used for nests that were used during the current breeding season. Nests used in a previous breeding season (6-12 months ago for most species) should not be coded with UN.
  • FAQs: the FAQ page got a major update. Look there first if you have a question, but feel free to reach out toinfo@californiabirdatlas.org if you have an inquiry that’s not addressed.

A small sample of some of the images that caught our eye this week. Tag your media with breeding-related behaviors for easier discovery.

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Atlas Dispatch: Jan 8-31, 2026 Rewind