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Surveying Western Yellow Bats in Coachella Valley

Over a period of three years, San Diego Natural History Museum biologists are surveying 32 native palm groves, or palm oases, and riparian areas within the Coachella Valley to study the bat species these habitats support. With funding from the Coachella Valley Conservation Commission, this study builds on previous surveys conducted in the lower Colorado Desert by Danielle Ortiz and Cameron Barrows in 2012.

For this study, we are focused on the western yellow bat (Lasiurus [=Dasypterus] xanthinus). It is a California Species of Special Concern and a target for regional conservation and management under the Coachella Valley Multiple Species Habitat Conservation Plan (CVMSCHP). (Technical note: The western yellow bat has been taxonomically split from the southern yellow bat (L. ega), which is a Covered Species under the CVMSHCP.)

Led by our Bat Specialist Drew Stokes, our team is documenting western yellow bat presence, activity levels, and palm grove locations that support breeding females. We are also collecting landscape and vegetation metrics to compare habitat selection models with the 2012 study. In the process, we're creating an inventory of the entire bat community in the Coachella Valley.

Thus far, we have documented western yellow bats in 31 of the 32 surveyed palm groves and riparian areas. Based on acoustic recordings and mist net captures, the canyon bat (Parastrellus hesperus), followed by California myotis (California myotis) and western yellow bat, are the most commonly detected and captured species. While the former two species are already known to be ubiquitous in southern California desert environments, it is surprising to see that the western yellow bat is also active and widespread throughout the area.

Not only is this study documenting where these species occur, it's also providing detailed data on how the habitat is being used. For a species like the western yellow bat, this can be especially important, as previous Museum surveys suggest that sexual segregation and roost selection is occurring among palm groves. If we can successfully document which palm groves support breeding females and which support juvenile recruitment, these locations can be designated as areas of high conservation priority within the CVMSHCP.