Date: 8/6/26 4:22 pm From: Tom Benson via groups.io <thomasabenson...> Subject: [inlandcountybirds] California Bird Atlas summary for Riverside County through early August 2026
First, thank you to everyone who has participated in the California Bird Atlas and contributed observations to Riverside County. Now that the breeding season is winding down for most species, I am providing a brief summary of atlas progress for Riverside County. If you are not yet a part of the atlas and want to join, please visit https://ebird.org/atlascalifornia/home. If you are already participating and want to know where in Riverside County you can make an impact, please explore the Riverside County atlas page or contact me directly.
Tom <Bensonthomasabenson...>
RIVERSIDE COUNTY
Blocks with data 280/734 (38%)Blocks with confirmed species 192/734 (26%)Species coded 203Species confirmed 139Number of atlasers 419Effort hours 1924
With 139 species confirmed, Riverside is the eighth-most speciose county in the state with respect to the atlas.
BLOCKS
Blocks with highest number of confirmed species [Atlas block (# species confirmed) - notable hotspots]Riverside East NW (53) - UC Riverside and Black Widow RanchRiverside East NE (39) - Box Springs Mountains, Hidden Springs Trail, Black Widow RanchRiverside East CE (29) - Sycamore Canyon, Box Springs Mountains, Rankin’s yardRiverside East CW (27) - Andulka Park, Canyon CrestVail Lake NW (27) - Vail LakeCorona North CW (26) - Prado Wetlands, Santa Ana RiverEl Casco SW (26) - San Jacinto Wildlife AreaLake Elsinore SW (26) - Lake Elsinore
While these atlas blocks are off to a good start, only about ½ to ¼ of the species potentially breeding in these blocks have been documented. During the remaining four years of the atlas, these blocks will benefit from both general atlasing and focused efforts targeting “missing” species, probably away from well-worked hotspots.
Of the remaining 732 atlas blocks in the county, 26 blocks have 10-25 species confirmed, 158 blocks have 1-9 species confirmed, and 542 blocks have no species confirmed. Most of the atlasing in the county has been conducted on the coastal slope or in the San Jacinto Mountains, with more limited efforts in the deserts in the Coachella Valley and the north end of the Salton Sea, at Desert Center, and along the Colorado River. The vast majority of the desert and large portions of the mountains and the southeastern corner of the coastal slope remain unsurveyed. Clearly, much atlasing work still needs to be done throughout the county. While many areas of the county are remote or difficult to access, many are accessible via paved roads within an hour drive of population centers in Orange, Los Angeles, and San Diego counties. These include all the blocks on the coastal slope, and many of the blocks in the mountains, Coachella Valley, and the vicinity of Joshua Tree National Park, all of which would benefit from additional atlas effort. For those of you who live in Riverside County, consider atlasing at home, in your neighborhood, or at a local park to help confirm additional species in undercovered blocks.
SPECIES
Top 10 [Species (# blocks confirmed)]House Finch (59)Common Raven (42)Bushtit (35)Red-tailed Hawk (33)House Sparrow (33)California Towhee (31)Black Phoebe (29)European Starling (29)Cliff Swallow (28)Lesser Goldfinch (28)
The following species were not confirmed during the first year of the atlas, although some late breeders might still be confirmed before the end of the year. While many of the species on these lists are very localized, secretive, nocturnal, or difficult to access, some are uncommon to common breeders that are widespread in appropriate habitat. [Note that my knowledge of the breeding birds of Riverside County is limited, so the following lists represent my best educated guess. Feedback regarding additions or subtractions welcome.]
Unconfirmed species [Definite or probable breeders]Graylag GooseSwan GooseEgyptian GooseMountain QuailInca DoveCommon Ground DoveYellow-billed CuckooLesser NighthawkCommon PoorwillRidgway’s RailVirginia RailNeotropic CormorantLeast BitternWhite-tailed KiteGolden EagleSpotted OwlLong-eared OwlWestern Screech-OwlNorthern Saw-whet OwlWilliamson’s SapsuckerGila WoodpeckerDowny WoodpeckerPrairie FalconOlive-sided FlycatcherGray FlycatcherDusky FlycatcherCassin’s VireoPinyon JayClark’s NutcrackerRuby-crowned KingletRed-breasted NuthatchTownsend’s SolitaireHermit ThrushPin-tailed WhydahPurple FinchCassin’s FinchRed CrossbillPine SiskinGrasshopper SparrowScott’s OrioleMacGillivray’s WarblerWilson’s WarblerSummer TanagerWestern TanagerLazuli Bunting
Unconfirmed Species [Possible - historical, occasional, or potential breeders]Blue-winged TealBlack SwiftCalliope HummingbirdSoraWilson’s SnipeWestern Cattle EgretTurkey VultureCommon Black HawkZone-tailed HawkBelted KingfisherFlammulated OwlWillow FlycatcherGray VireoPlumbeous VireoBronzed Cowbird
