Wednesday, July 16, 2008
Minnesota's deer-gleaning bats
Are insectivorous bats attracted to mosquitoes attracted to deer? Apparently they are.
Willy4003, a serious recreational camera trapper from Floodwood, Minnesota got me to thinking about this when he posted recent photos of bats and deer on the Pixcontroller Forums, and he kindly gave me permission to post them here.
Willy's cam was set at "an established mineral lick surrounded by ash and spruce near a marshy lowlying area, hence the extensive mosquito population." His photos were taken between 9:28pm and 12:18am on June 16th, and July 6th and 7th.
I put the question to my old mammalogist buddy Don Wilson, who is a bat aficionado of the first order. He responded: "I haven't ever heard of anything like that. Seems especially unusual in Minnesota, where the species diversity of bats is low, and foliage gleaners are not at all common. Very interesting."
The term "foliage gleaner" (not yet in Wiktionary) refers to birds, bats, and insects that forage for insects in vegetation by hovering, swooping, darting, and diving at their prey.
Deer are powerful mosquito bait, and they also play into the life cycle of a number of other dipteran (fly) parasites, like nasal and skin bots. Biting flies and mosquitoes couldn't ask for a better host than a deer in summer, when the thin coat renders most of the body vulnerable to blood-suckers. This cropped photo shows the mossies tanking up, and judging from the red spots, this doe probably has an itchy udder.
Of course, the bat-deer association could just be a coincidence. The bat might have just been flying by. But I have the feeling that if camera trappers had faster cameras, there might get a lot more pictures of bats and deer.
It goes to show, there's still plenty of natural history to be learned, and camera traps are a good way to do it. A hat tip to Willy 4003 for sharing this neat finding.