Bat strafes owl

It's not unusual for a bat to glean insects buzzing a mammal.

Occasionally fellow camera trappers in Minnesota photograph bats very close to deer covered with mosquitos, and it's obvious what the bats are doing.

What you see in this video clip however is a little odd.

The pools in this creek are swarming with insects, so there's no reason for the bat, probably a species of Myotis, to hit the owl in the head.

That is, unless something else is going on.

Could the bat be mobbing the owl, the way songbirds mob owls?

Or did it's radar fail?

This is the kind of footage that reinforces my obsession with camera trapping.

If you are curious about nature, get yourself a camera trap.

You'll learn a lot while you are having fun.

Saltos Canyon

Saltos Canyon may have its waterfalls in January, but most of the year it's a dry canyon with a few seeps and stagnant pools.

In late September we searched the lower reaches of the canyon for water where we might place some cameras.

The only water we found were a few small pools, and yellow jackets lined the seeps like drunks in a bar.

The potability of the water is another question.

It leaves a rime when it evaporates, possibly a derivative of gypsum which is abundant there.

But few vertebrates can live without water so we continued our search for a suitable place to set a camera.

After a mile and a half the canyon opened up, and we found a pool pocked with hoof prints.

We set a cam there in the shade of the mule fat.

We returned a month later. 

Wood rats, Peromyscus, and a Heermann's kangaroo rat visited the puddles.

Though kangaroo rats and pocket mice can live on metabolic water from their food, a photo of a drinking k-rat would have been a prize.  

Black-tailed deer and cottontails also showed, but they weren't regulars.

Bobcats were more frequent visitors.

Two of them, though not together, were often snapped in a swarm of moths. 

So the bats were there too. 

Baby bat CSI

The fuzzy thing I felt in the pool strainer was a dead bat.

It was so small I thought it was a western pipistrelle, but on closer inspection I saw that it was probably an immature Myotis.

What happened?

Was it roosting under the roof tiles of the house and fell into the pool on its maiden flight?

Or was it hanging from its mother's nipple and fell off when she skimmed the pool for a drink?

Any learned explanations out there?

(PS: I measured it and preserved it as an alcoholic specimen for the California Academy of Sciences.)

One more from the night roost

Here is one more bat, the third species that roosted in the sandstone cave. 

It is distinctly darker than the long-eared species of Myotis, and I suspect it is either the Yuma myotis (Myotis yumanensis) or the California myotis (Myotis californicus). 

You can tell them apart by the size of the feet. The California myotis has little feet.

Getting bat pictures is gratifying, but you need high quality photos to identify bats to species, and even that is not always enough.

Sometimes you have to look at their teeth.  

Now to see some truly excellent bat photos that show diagnostic characters, have a look at Michael Durham's webpage here.  

Night roost

The sandstone cave yielded 602 photos, but only 274 were of animals.

The low success rate of 46% was due to false triggers caused by bats.

They zipped in and out of the cave seeking a place to settle, and this triggered the camera.

Even so, we got 117 bat photos, and this yellowish brown bat with biggish ears was the most commonly photographed species.

Two species fit the bill -- the big-eared myotis (Myotic evotis) and the fringed myotis (M. thrysanodes).

The distinguishing characteristic, a fringe of hair along the interfemoral membrane would make it the latter.

None of the photos is clear enough to see it.

I am not confident of this identification, so this is a call to any mammalogists out there to speak up.

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.