365 Urban Species. #114: Big Brown Bat

[urbpan]

Urban Species #114 Big brown bat Eptesicus fuscus

The most urban of all North American bats, the big brown bat roosts almost exclusively in man-made structures. A few colonies have been found in hollow trees or caves, but for the most part, these animals prefer attics, barns, and belfries. As they are among the most cold-tolerant of bats, they will roost in more open places, such as under bridges and in chimneys. They are the first bats seen awake in late winter, and the most commonly seen bats in our area. They feed on insects over still water and open areas, and are also frequently observed taking advantage of the bug-attracting properties of streetlights.

Perhaps the most famous urban bats are those that make up the colony of Mexican free-tailed bats (Tadarida brasiensis) in Austin. Someday I dearly wish to see the spectacle of more than a million bats (the largest urban colony in the world) stream out from underneath the Congress Avenue bridge.

Comments

[dragonwrites.livejournal.com]

that sleeping bat photo is spectacular. but if that is a "big" brown bat, are there little brown bats? and how tiny are they?

i think i've removed a couple of these babies from my friends' house. all the guys living there were blind or confined to a wheelchair, so it was up to me to coax the bat into a 32 oz. soda cup, slide a piece of cardboard over the opening, and release an extremely disoriented creature into the backyard. they always found their way back in, tho.

they have the most adorable faces. too back you can't see that in the picture.

[urbpan.livejournal.com]

I wondered if someone was going to ask that!

The little brown bat (Myotis lucifugis), listed by some sources as "little brown myotis" has about a ten inch wingspan, while the big brown bat has about a 12 inch wingspan. On average, the big brown bat is half again as heavy as the little brown (12-16g as opposed to 7-10g). According to Godin's Wild Mammals of New England, "big brown bats can be recognized by their large size and slow wing beats."
(not by me, they can't)

Little browns roost in attics and barns in summer, but in winter hibernate in caves and mines. Big browns are the only bats known to hibernate in buildings. (according to Godin, again) They range fairly far north (to southern Alaska) but are generally less cold tolerant than big browns. Little browns are more heat tolerant than big browns.

[urbpan.livejournal.com]

Also, more bats (including their adorable faces) can be seen here.