Bats and Moths: New Figures

[David Wagner]

In a previous posting I requested information about the bat colony in 
Austin, Texas.  I got several responses and thought I'd share the more 
conservation (safer) figures that were mentioned on one of the web sites 
about the colony.

The bat:  Mexican free-tailed bat
The colony size:  roughly 1.5 million
Insect biomass consumed each night:  10,000 to 30,000 lbs
Web sites with more information:
http://www.io.com/house/batstory.html;
http://austin360.com/local/bats2/batstory.htm;
http://www.ci.austin.tx.us/health/hlbsbate.htm


These numbers are at odds with others sent to me by Tony Thomas for a 
Nevada colony of Brazilian free-tails

"In the Great Basin National Park, one colony of 50-80,000 Brazilian 
Free-tailed bats are estimated to eat 300 million insects/night"
according to Bradley, P.V. 1996. Nevada's Night Flyers. Natural History 105 
(2): 73-76.


Food for thought so to speak:  I am sure the biggest one-night haul that I 
have ever emptied out a Koehn bucket trap was less than a pound (of moths), 
with many nights logging in with but a few ounces.
*************************
David L. Wagner
Ecology & Evolutionary Biology
v. 860-486-2139; f. 860-486-6364
dwagner at uconnvm.uconn.edu