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Lesser long-nosed bat


The lesser long-nosed bat (Leptonycteris yerbabuenae, LEYE) is a nectarivorous bat known to occur from southern Arizona and
New Mexico into western Mexico and Central America. Individuals can be quite large and range in size from 74 - 90 mm in total body length and 350 to 360 mm in wingspan and weigh from 15 to 29 g. Individuals undertake a long seasonal migration in order to follow the flowering cycle of their primary food sources, columnar cacti and agave. Large numbers of female LEYE arrive in southwestern Arizona by late April to have their pups and feed on abundant blooming saguaro cacti, leaving these roosts by mid-July, many of them moving east to feed on blooming agave in southeastern Arizona. LEYE are primarily present in eastern Pima County during late summer and early fall, largely feeding on flowering Palmer’s agave.

There are no known sites on Pima County preserves where this species roosts, though LEYE is known to forage on County lands in the Cienega Valley. Should a roost be located on Pima County preserve lands, the County will be responsible for annual monitoring of that site (using an exit count protocol) in coordination with the Arizona Game and Fish Department and US Fish and Wildlife Service.  Before an exhaust system caused colony abandonment in the 1960s, Colossal Cave hosted a maternity roost of this species. In recent years, LEYE has been captured during bat surveys at County preserves in the Rincon Mountains and Cienega Valley. This species was listed as endangered by USFWS in 1988, however it was delisted in 2018 due to species recovery.

Pima County’s bat monitoring objective is to monitor the occupancy, site condition, and associated management needs of a subset of roosts used by the Mexican long-tongued, Lesser long-nosed, California leaf-nosed, and Pale Townsend’s big-eared bats on Pima County open space lands.  Monitored roosts will be those roosts that have particular importance to the local population of these four bat species. The County will also work towards documenting all of the known roosts sites for these species that are located on County lands, though not all will be chosen for additional monitoring efforts. Where possible and relevant,  results from these inventory and monitoring efforts will be used to guide the management (i.e., gating) and/or restoration of key features that will benefit these and other bat species.

Photo by Alex Badyaev (University of Arizona)