Over thirty species of mammals are known or expected to use the natural foothill communities in the San Gabriel Mtns., either daily or on a seasonal movement basis. Our remote wildlife camera program at the Rosemont Preserve has captured mountain lion, black bear, coyote, gray fox, bobcat, raccoon, opossum, Audubon’s cottontail, brush rabbit, Western gray squirrel, California ground squirrel, California mouse, brush mouse, and mule deer. Also, dusky-footed wood rat (dens), and Botta’s pocket gopher (burrows) was observed on the properties
While focused surveys for bats have not been conducted, several species, such as western pipistrelle, big brown bat, California myotis, and hoary bat would utilize the area – unidentified species of bats have been observed on the Preserve.
Currently, about 56 species of birds have been recorded at Rosemont, and lists documenting these have been entered by birders into the eBird public database (https://ebird.org/hotspot/L2361811). Regularly seen species include: red-tailed hawk, California quail, band-tailed pigeon, mourning dove, Anna’s hummingbird, acorn woodpecker, Nuttall’s woodpecker, Northern flicker, western wood-pewee, black phoebe, ash-throated flycatcher, Northern rough-winged swallow, cliff swallow, California scrub-jay, American crow, common raven, oak titmouse, bushtit, canyon wren, Bewick’s wren, house wren, wrentit, Northern mockingbird, California thrasher, phainopepla, European starling, Yellow-rumped Warbler, Wilson’s warbler, spotted towhee, California towhee, song sparrow, house finch, lesser goldfinch and house sparrow. Owls have been heard, but the species not identified.
Amphibians and Reptiles
The most common reptiles expected at Rosemont are side-blotched lizard, Western fence lizard, Western whiptail lizard and San Diego alligator lizard, gopher snake and Pacific rattlesnake. Additional species of amphibians and reptiles that have been recorded in the vicinity along the foothills of the San Gabriel mountains are likely present. These are western newt, Monterey salamander, black-bellied slender salamander, western toad, pacific chorusfrog, California chorusfrog, California striped racer, patch-nosed snake, California kingsnake, California mountain kingsnake, rosy boa, two-striped garter snake, Western blind snake (rare) and ring-necked snake.
At least several hundred species of insects, spiders and other invertebrates are expected to utilize the site. Butterflies have not been systematically surveyed, but the following species have been seen during preliminary fieldwork, and indicate a healthy ecosystem: Western tiger swallowtail, pale swallowtail, cabbage white, orange sulphur, cloudless sulphur, Sara orangetip, monarch, gulf fritillary, mourning cloak, red admiral, painted lady, California sister, California hairstreak, pygmy blue, echo azure, and a duskywing species.