Bat


by Kathleen Cahill

Numerous myths and superstitions persist regarding bats, making them disliked and feared. These myths have flourished because bats are among the world’s least understood animals. Although bats have been around for 50 million years and can be found around the world, their numbers are decreasing. Many species of bats have become endangered as a result of habitat loss and direct intervention by humans fueled my misinformation. Far from being dangerous and frightening, bats are environmentally valuable, interesting animals.

There are more than 900 species of bats, 25 of which are found in California. These include the Big Brown Bat, Hoary Bat, Yuma Bat, and the Mexican Free-tailed Bat. Like dolphins, most bats communicate and navigate with high-frequency sounds. Bats give birth to one pup typically  in May or June. The baby is helpless until it learns to fly one month later, quickly becoming independent. Bats can live up to 30 years. Bat social behavior varies between species: some bats live in colonies of thousands and others are solitary. Bats are found living in caves, animal burrows, plants, and buildings.

Contrary to common belief, the vast majority of bats are not vampire bats. Vampire bats are only found in Latin America, and they make up a tiny fraction of all bat species (vampire bats are much more likely to feed on the blood of animals than of humans in any case).

The vast majority of bats are insectivores and the rest feed on fruit, mice, and small vertebrates. Because so many bats consume insects, they are very valuable in keeping the insect population down. One bat can catch hundreds of insects in an hour.

Bats perform other vital functions as well. They are the sole pollinator of some keystone plant species. In the tropics, the seed dispersal and pollination activity of fruit- and nectar-eating bats are vital to the survival of the rain forests.

A major threat to bat populations is habitat loss. This is one reason why bats take advantage of access to attics and other man-made structures. If you would like to help combat this and provide bats with alternate housing, consider putting up a bat house in your yard. Bat houses are compact and take up minimal room. In our climate, they should be placed where they can receive 6-8 hours of sun per day. Learn more about bat houses through http://batcon.org.

Preventing a Problem
Walk around the exterior of your house to look for places that can serve as a point of entry for bats. Bats can fit through very tiny spaces, so your search must be thorough. Bats do not chew holes in walls or electrical insulation. Watch out for:

  • Unscreened windows; uncapped chimneys; loose-fitting screen doors
  • Doors with a space at the bottom (buy a draft guard)
  • Any hole greater than one-half inch in diameter or a crack .25” x 1.5” or greater

Openings should be closed with steel wool, duct tape, or a screen.

Removal of a (healthy) individual bat

If the bat is awake:
Open all doors and windows in the room that lead outside. Close off the rest of the house. You may wish to observe from outside to verify the bat leaves the house.

If the bat is asleep:
Without touching the bat, gently scoop it into a small container (like a shoebox) using a cloth or a piece of paper. Put a soft cloth into the box to give the bat something to cling to. Cover the box and place it where it cannot be disturbed by pets or children, and allow it to awaken before releasing. Before a bat is able to fly, it needs time to warm up as it comes out of sleep. When the bat is awake, release it outside. Remember, bats are wild animals and potential rabies vectors, so you should never touch a bat directly with bare hands.

Removal of a Bat Colony
Most bat colonies naturally leave their roosts in the fall, so this is the best time to bat-proof your house for next season.

If you don’t want to wait until fall, watch as the the bats leave at dusk to feed. Observe point of exit, and cover exit. DO NOT do this during the summer months (June – August). This is when flightless young are present. It is inhumane to separate a parent from dependent offspring.

What to do if you find an injured bat
If you find a sick or injured bat in your house or yard, leave it alone. Call the Wildlife Center for further information.

Consider building a bat house
Bats are living in attics and other human dwellings because they are facing a serious loss of habitat. Bat houses are compact and take up minimal room. In our climate, the optimal placement is where they can receive eight hours of sun per day. Bat houses can be purchased through www.batcon.org or build your own!

Wildlife Center of Silicon Valley
3027 Penitencia Creek Road
San Jose, CA 95132
1-408-929-9453 (929-WILD)
info@wcsv.org

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