Water For Wildlife

This California myotis is just one of the dozens of western bat species that depends on livestock water developments to meet their daily water requirements.

The Water for Wildlife project was created to restore safe drinking water for countless thousands of bats, birds, and other animals that are accidentally excluded from or drowned in livestock water developments each year in the western United States. Water resources, especially in arid and semi arid areas of the west, are vital to wildlife survival.

As natural water sources have been depleted, livestock water developments have become one of the few sources of water supplies available for wildlife.

Livestock water developments were not designed with wildlife in mind, and many animals drown while attempting to drink or bathe in them, particularly when escape structures are absent or inadequate, water levels are low, and during drought.

Mark Brown of the Arizona Game & Fish Department and Stu Tuttle of the USDA-Natural Resources Conservation Service inspect a trough in the House Rock Valley of Arizona.

Obstructions over or adjacent to these water developments, like fencing and bracing, can reduce or deny access for animals that drink on the wing such as bats, swallows, and nighthawks. These animals need an unobstructed swoop zone to and from the waters surface, and collisions with obstructions can result in injury or knock them into the water.

Bat visitation rates at livestock water developments can be extremely high, with a new bat swooping in to drink every second on hot evenings. Bats have a high need for water intake and are especially vulnerable to dehydration, sometimes losing 30% of their body weight in evaporative water loss in a single afternoon.

Evidence suggests a strong relationship between bat species abundance and availability of open water for drinking (Adams 2003). Loss of just one water site can eliminate multiple bat species from a wide area.

The following quote from Evolution of a Desert Mammalian Fauna (Stangel, Dalquest, and Hollander 1994) illustrates the history of the issue:

In the study area, netting sites were usually the circular, above-ground stock tanks of metal or concrete which are supplied by windmills. These tanks are often the only source of water for miles around, and are frequented nightly by locally resident bats. Such sites, however, are few and widely distributed. The circular stock tanks sometimes also serve as traps for many bats, probably most often when water levels are low. Our only specimen of Lasionycteris noctivigans from the Delawares was found floating in such a tank, and we have also salvaged Pipistrellus hesperus, Antrozous pallidus, and Tadarida brasiliensis in a similar manner. Dredging of the sediments of these tanks, perhaps coinciding with the periodic draining for maintenance purposes, might also provide a valuable long-term sampling method for a variety of bat species.

Fortunately, wildlife escape structures can be inexpensively and easily constructed to virtually eliminate wildlife drownings, and fencing and bracing methods exist that can enhance access for bats and other wildlife while meeting livestock management objectives.