The Bat & Hummingbird Study has moved!

If you are interested in the hummingbird feeder monitoring study, please go to the new web page at AZ Game & Fish Department website.

Photo by Doris Evans

Photo by Doris Evans

Background on the study

Data collected from this study will be used by scientists to better understand the lesser long-nosed bat, a species listed as endangered under the federal Endangered Species Act. It will also be used by the Town of Marana and the City of Tucson in development of their Habitat Conservation Plans.

Purpose of the study

By gathering data on where bats are feeding, when they arrive and leave the Tucson Basin, and tracking a few bats with radio transmitters, we can gain a better understanding of their foraging habitat, how they travel from their roosts to foraging sites, and the locations of their roosts. This will allow us to plan more effective conservation strategies and minimize any impacts we might be having on this endangered species. 

Background on the lesser long-nosed bat

Lesser long-nosed bats (Leptonycteris curasoae yerbabuenae) are migratory and spend their winters in Mexico, returning to Arizona as early as the second week in April. Pregnant females congregate at maternity roosts, give birth, and raise their young throughout the summer. Males form separate, smaller colonies.
Nectar and pollen from the flowers of saguaro and organ pipe cactus are the core of the bats' diet in early summer. Later in the summer, as they move up in elevation, they feed on agave. Their spring migration from central Mexico northward is thought to follow the sequential blooming of certain flowers from south to north. Bats have also been observed using hummingbird feeders near residential homes. Hummingbird feeder monitoring has been on-going in the Tucson Basin since 2006. 

What we’ve learned from previous years of this study

Thanks to our citizen-scientist volunteers, we were able to capture and put radio transmitters on bats for a duration of three to four days. During this time AZ Game & Fish Department identified new information on movement corridors, and was able to follow bats as they returned to two significant day roosts that were previously unknown for this species. In addition, AZ Game & Fish Department located specific foraging patches within the urban and ex-urban interface of the Tucson basin. The character of these activity areas ranged from high density urban core to low density rural conditions. Movement distances from day roosts to foraging patches exceeded 40 km (25 miles) for a one-way flight.

How to distinguish between Leptonycteris (Lesser long-nosed bats) and Choeronycteris (Mexican long-tongued bats)

It is not difficult to tell these two bats apart. The easiest way is to check the bat’s back end. Lepto lacks a broad tail membrane between its hind legs and its legs are ‘free’ with an open space between them. Choero has a broad tail membrane and its legs are not ‘free.’ This difference is sometimes described as ‘pants’ (Lepto) vs. ‘skirt’ (Choero). Other distinguishing features include: Lepto has a shorter, heavier snout whereas Choero has a longer, thinner snout; Lepto has a gently sloping forehead whereas Choero has a steeper forehead; and Lepto has larger eyes and rounded ears whereas Choero has smaller eyes and more pointed ears. Adults of the two species also differ in color: fawn brown in Lepto and gray in Choero. But young Leptos (the most common visitors to feeders) are also gray.