Monument Volunteers Help with Bat Research

close-up of a yellow bat
A yellow bat

Usually in September, people start the school year by asking their friends about the places they visited and the things they did over the summer – with typical answers like “visited family out of state, or hung out by the pool.”  But for a few volunteers of the Santa Rosa and San Jacinto Mountains National Monument, their answers were far from that usual reply.  They have been active for the past five months assisting Danielle Ortiz, Natural Resource Specialist with the Santa Rosa & San Jacinto Mountains National Monument, conduct research on bats throughout the Colorado Desert.

Danielle and the volunteers have visited 42 different palm oases throughout the Colorado Desert region in an effort to learn about the roosting preferences of the western yellow bat (Lasiurus xanthinus) in palm oases, as little is known about the yellow bat and it is a California Species of Concern.  The study is looking into whether certain parameters of a palm oasis attract or repel yellow bats from roosting at the site such as skirt length of the palms, fire history, size of the oasis, presence of the invasive tamarisk, proximity to water, and human disturbance (such as a trail).

Conducting the research with the temperatures over 100 degrees has been a challenge, especially considering that we have already hiked over 200 miles in the desert and still have a few more weeks of surveys to go.  The research efforts have involved counting the number of palm trees in every oasis (some have had more than 2,000 palms), photographing the area, and monitoring bats around the palm trees with an Anabat bat detector and spotlights.  (Observing the bats with the bat detector and spotlight is similar to bird watching – most species have a unique echolocation call, but since there can be some overlap it is important to get a visual with the spotlight).  We have been lucky to see a number of bats drop out of the palm tree skirts, indicating that the western yellow bat is using the palm skirt as a place to rest during the day.  Many other bat species have been observed as well — such as canyon bats, pallid bats, spotted bats, big brown bats, free tail bats, and various myotis species.  (story continues below)

two women watch for bats in the dark under palm trees
Ada and Lynn actively monitoring for yellow bats at Dos Palmas.

Not only have we been learning a lot about bats during the study, but we have also been learning a lot about the nocturnal creatures that we have encountered during our nightly excursions.  So far we have been lucky to see bighorn sheep, coyotes, kit foxes, ringtail cats, raccoons, mice, lizards, snakes (including various rattlesnakes), frogs and toads in addition to numerous bat species during our nightly excursions!  Every night has been an adventure, packed with fun and a greater appreciation of bats. Everyone involved has learned a lot through this project about the various species of desert bats that inhabit the Colorado Desert region, as well as flight patterns and behavior of some of the local species.  At the end of the day, everyone has a greater appreciation and interest in bat conservation (the youth volunteers are even doing more studying on bats for school biology projects as a result of their involvement!) – GO BATS!!!!

hikers head past desert palms
Ada and Ben heading toward a palm oasis.

boy shines a spotlight in the dark
Conner prepares to spotlight bats.

 A canyon treefrog spotted in the dark
A canyon treefrog spotted among the rocks.

an owl among desert foliage
a great horned owl among desert foliage