Water for Wildlife

In the arid regions of the western United States, natural water sources have been disappearing quickly.  That means that bats and other wildlife (e.g., insect-eating birds like swifts, swallows, and nighthawks) increasingly rely on troughs, watering tanks, and ponds maintained for livestock.  However, such artificial water sources can be deadly for wildlife if the structures are not installed and maintained properly.  Fortunately, with minimal cost or effort, ranchers can protect bats and other wildlife without reducing the usefulness of artificial water sources for livestock.

To get water, bats fly down to a water surface, scoop up a drink, and then keep flying up and away from the water.  This requires an unobstructed “swoop zone,” just like airplane pilots who need clear approaches to runways.  Bats also need properly designed and placed escape structures within the water structures.  Additionally, water levels must be maintained at adequate levels.

Field data indicate that most bat species need open water surfaces that are at least 10 feet long and 2.5 feet wide.  A few species need even longer lengths, from 50 to 100 feet.  Obstructions such as bracing, fencing, posts, vegetation, and even algae can severely impede bats’ access to water sources.  Troughs should be constructed and maintained to eliminate these hazards.

Escape structures are critical to keep bats and other wildlife from drowning.  A properly installed escape structure reaches all the way to the water surface, extends all the way to the edge of the trough or tank, and has a rough surface to aid animals in climbing out.  Furthermore, the escape structure must have vertical sides that extend all the way down to the water and meet the inside wall of the trough or tank.  A simple ramp from the top edge of the structure to the water surface is inadequate; a trapped animal will swim around and around the perimeter of the structure and under the ramp, never finding the way out.

Finally, water levels in troughs and tanks must be maintained at adequate levels.  When water levels drop even a few inches below the rim, bats and other animals can be trapped easily unless an escape structure is provided.  Also, if water levels fluctuate greatly within a tank, it is very important that the escape structure extend all the way to the bottom of the tank.