Blue Ridge Wildlife Center Patient of the Week: Tri-Colored Bat

Happy  Halloween  Bat Week!

Bat Week is an international, annual celebration designed to raise awareness about the need for bat conservation. This adult female Tri-colored Bat is one of those that truly needs protection. This patient was observed hanging on a concrete wall for several days without moving, which is abnormal behavior for bats.

Upon admission, the bat was extremely alert and defensive, flipping on her back and chattering her teeth at staff. It’s hard to say why she was quiet and in one area for so long—she could have hit a window, become too cold to move on a chilly night, or suffered some other type of trauma.

Here you can see the reason for their name! They have fur that is colored dark, light, dark from root to tip (hence, the “tri” in the name) that ranges in color from yellows, to reds, to silvery-browns. They have short, rounded ears with a straight tragus (inner ear) and small blunt snouts.

Tri-coloreds are small in stature, maxing out at about 8 grams in weight (1 gram = paper clip). They also have bright pink “arms” visible on their undersides.

Doing what bats do best—camouflaging and hanging out! During warmer months, tri-coloreds primarily roost in trees among the leaves, pine needles, mosses, etc. They have also been documented roosting in barns, under porches or bridges, and in other man-made structures.

Warmer months, which is also breeding and birthing time, females sometimes form maternity colonies and switch roost trees regularly while males roost singly. Females also show high site fidelity, returning each year to the same summer roosting locations.

When the cold weather comes and it is time to go into torpor (temporary hibernation), these bats head to their hibernaculum (place to hibernate) caves! Mostly solitary in nature, small groups may form during torpor time.

A little brown bat with white-nose syndrome. Credit: Marvin Moriarty/USFWS

Tri-colored Bats are declining in numbers rapidly due to White Nose Syndrome (WNS), habitat destruction, and effects of global climate change. WNS is a fungal infection that spreads in damp areas, like the caves and crevices used during winter torpor. The fundus causes skin and respiratory inflammation, which wakes the bats prematurely and for long periods as they scratch their irritated skin. Winter colonies affected by WNS have seen a 90 to 100% loss in population at sites impacted by the fungus. Without food or other resources to survive the winter, these small bats quickly dehydrate and starve to death.

Tri-colored Bats are categorized as State Endangered and are tier 1a in Virginia’s Wildlife Action Plan—due to their dwindling numbers, they were also submitted for Federal Endangered status last year. Thank you for supporting the Center so that we can support our area’s most vulnerable species!

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