Date: 5/21/26 8:52 pm From: Jamie Chavez via groups.io <almiyi...> Subject: [sbcobirding] The CA Bird Atlas Mid-Season Update
As of today, 97 species have been confirmed as breeding birds in the county since the CA Bird Atlas project kicked off in January. In addition, 161 of the county’s 317 atlas blocks now have data, thanks to 2,000-plus checklists submitted in the county so far!
This is only a mid-season report, which means there are still several months left in the 2026 season. If you’ve thought about participating but haven’t jumped in yet, now may be the easiest time to see and record breeding birds. Many species are currently caring for fledged young, building or sitting on nests, or conspicuously feeding nestlings. In eBird, simply join the [CA Bird Atlas](https://ebird.org/atlascalifornia/home) project to start atlasing.
If you are already an eBird user, this will feel very familiar to you. Did you know that you can do your everyday eBirding while using the atlas mobile app? The only real differences from a standard eBird checklist are that you need to stay within [atlas block boundaries](https://ebird.org/atlascalifornia/about/blocks) so your checklist remains within the block where you started, and that you make at least some effort to observe possible breeding activity and assign breeding codes. It only takes a couple of extra clicks per species entry.
In fact, I use the atlas checklist option every time I go birding because it functions almost exactly the same as a regular eBird checklist, while also contributing data directly to the atlas project. If you decide you do not want to submit an atlas checklist for a particular outing, you can simply toggle back to the standard eBird checklist before you begin. Keep in mind that breeding codes only apply to the atlas project when using the atlas checklist option; breeding codes entered on standard eBird checklists do not count toward atlas data.
As I look at some of the atlas checklists submitted over the past few months, I’ve noticed a common theme: I think that some participants assume they should only code probable or confirmed breeding birds, leaving all other species uncoded. In reality, it is preferred that you code as many species as possible every time you bird.
This is from the atlas information page on entering breeding codes:
> “For each species on a checklist, record the highest-level code for what you observed during the checklist period.”
For example, maybe last week you observed a bird feeding young (coded FY — confirmed breeding), but this week at the same location, you only see a pair in suitable habitat (P) or hear a singing male (S). You should code only what you observe at the time of the checklist, even if breeding had already been confirmed previously. This is not considered a downgrade; rather, it documents the highest breeding activity observed during that specific visit.
It is perfectly fine not to go into this level of detail, but for those who are motivated, the information is extremely valuable. These observations will eventually be used to produce detailed breeding phenology data for each species within every atlas block, documenting activity from the earliest signs of breeding through confirmed nesting. This includes species that do not breed here, but begin showing signs of activity before departing the area (singing Ruby-crowned Kinglet, for example). Just imagine how detailed the maps and breeding phenology information will be at the end of this five-year atlas project once this level of detail has been collected across every block and for every species.
To demonstrate the incredible amount of information already being collected in just a few short months, check out the new [CA Bird Atlas Blockboard](https://cba-blockboard.share.connect.posit.cloud/) progress dashboard. This tool tracks atlas progress and combines observations with eBird’s Status and Trends species models to generate expected species lists for each block.
