Rumination

This is not about meditation or deep thought or reflection. It's about digestion. It's also about walking slowly and keeping your eyes open (while avoiding obstacles underfoot). I took a stroll in the backyard today, and deep in the woods my eyes suddenly wandered over to the left where I saw a pair of eyes staring back at me. I'm farily certain that this was the same doe and fawn that visited me the other morning, and here I was paying them a call during their morning rumination.

Yup, she was having a quiet laydown to digest her morning's foraging. She was quite happy to just lie there and look at me for several minutes. Her fawn bounded off up the hill and that must have made her nervous because then she got up and stood in back of a tree with just her head showing, and then finally most of her body came out from behind the tree.

As I stood there watching her watching me, she began to regurgitate and chew; it looked exactly like someone chewing gum, with the same sideways grinding motion. And then looking a little more closely at her as she was chewing I could see her swallow as a noticeable bolus of chewed wad quickly made its way down her esophagus, and just as quickly another bolus came up. The transit time couldn't have been more than 1/2 second, which surprised me because when we swallow food, it takes several seconds to get it down. The yellow line is where I saw all this activity in her neck (I colored it in to make it more obvious).

You might think this is really geeky, but I spent 4 years at the Univ of Minnesota using radiography to film turkeys swallowing their food and so comparisons with how other animals manipulate and swallow food is kind of interesting.

Ruminants (like cattle and sheep, but not horses) may take a long time to digest their food by chewing it over several times, but this makes them more efficient at digesting it, so they can get by with poorer quality forage, like what the deer will have to eat this winter when the leafy greens are all gone.

Deer camouflage

Coming back to my car after taking sunset photos the other day, I came around a blind corner and found a beautiful doe standing between me and the car. She was as shocked as I was, but stood there quietly while I took several pictures.

Just minutes before I had been photographing prairie grasses, big blue stem in particular, which reached at least two feet above my head.

Looking at the deer I was struck by how similar their coloration was to those grasses, and wondered whether deer coloration is really camouflage. With a little help from photoshop, here's the result of my experiment: on the left the image of the deer from the top photo layered behind the the prairie grass and, on the right, the image of the deer disappearing into the prairie grass.

Is their natural camouflage in fall vegetation (prime reproductive time) just a coincidence or was their some selection for this coloration during a vulnerable period of their annual cycle? White tailed deer are widespread across the US and well adapted to a variety of habitats, but here in the upper Midwest, they are supposedly forest animals. It seems to me they favor forest edge more than interior forest, and I often see them bounding away through tall thickets toward the woods. In Minnesota the forest edge usually gives way to grassy fields, where the dominant native grasses produce tall, yellow-brown vegetation. Their natural predators, mountain lion (also nicely camouflaged in prairie grass) and wolf, could have hunted both forest and prairie and would have controlled population sizes better in historical times than hunting pressure from humans does today.

Even in mid-winter, deer seem well camouflaged against the tans and browns found in bark of most hardwoods. It could just be the lighting, but they do seem to be a slightly darker brown in winter than in summer and fall.

Garden Thief

Woodchucks did a number on the garden earlier this spring. I thought it was just one very large one eating out there, but then we began to see smaller ones moving around in the dense crop of coneflowers and cup plants just starting to grow. The wildflower garden is meant to survive on its own, without help from me (except for getting rid of noxious weeds), so I let the woodchucks alone. Within a week, however, the Golden Alexander (first blooming spring flower in the garden) was chewed down to its roots, Cup Plant was similarly mowed down, and the Spiderwort was on the verge of disappearing altogether. OK, enough of that. I decided I had to trap and remove the pests, especially "big mama".

After setting the largest live trap we had up in the middle of the garden and baited with what we thought were woodchuck delights (cabbage, carrots, apple and oatmeal), we caught a racoon instead of a woodchuck. Setting the trap in what we thought was their runway into the garden didn't help either. Then I noticed that the runway actually extended right to the edge of the yard, and there was a clear path down the hill into the neighbor's yard, leading right up to a big dirt mound with a large hole in one side of it. Aha -- this must be the nest.

What a surprise when I went to set up the trap right at the burrow and found 5 baby woodchucks sunning on top of the dirt mound. So, if I was going to protect the wildflower garden, I would have to remove 6 woodchucks, and so far I hadn't been able to trap even one.



Here are 4 of the 5 babies basking on top of their burrow. I had to peer through the leaves to photograph them because they were rather shy. Finally, after many attempts I managed to catch the mom and then 4 of her 5 babies. The last one was very savvy and eluded me for almost two weeks, but I finally got him. I drove them about 5 miles away to a big county park and let them go there. Maybe they managed to find each other. Good riddance.





Did you know that woodchucks (aka groundhogs) are actually the largest member of the squirrel family in the upper midwest? The MN DNR website recommends spraying a solution of 2/3 water to 1/3 ammonia solution on plants you care about in your garden. If it tastes bad enough, woodchucks will leave it alone. I'll try that next year.

Woodchucks are among the largest hibernators (contrary to popular belief, bears do not hibernate), with adults spending probably only 5-6 months above ground in MN feeding, raising babies, and fattening up for the next long "sleep" cycle. Hibernation isn't really sleep, in the same sense that we sleep. It's more of a deep coma, with markedly reduced breathing, heart rate, and absence of reflexes. Puxatawny Phil might emerge in February to check out the remaning length of winter, but I bet MN woodchucks stay put until the ground thaws in April. .

in the Austin, Texas backyard

This week we have experienced the great Texas heat wave up close and personal. They are working on a record 42 straight days of > 100 F temps, which make it really hard to want to go outdoors. But we did venture out one night, when the already excessive air temperature was added to by the re-radiation from the concrete and steel of the downtown buildings. Why did we subject ourselves to this? To see the emergence of 1.5 million Mexican free-tailed bats at sunset from the Congress Street bridge. This daily occurence is quite famous, and draws hundreds of people each night that line up on and below the bridge to watch.

Minute cracks in the underside of the bridge are the perfect size for these bats to climb (or fly) in and create their communal roosts. They arrive here (from the south) in March, and breed and raise young, migrating south again in September. I assume the moisture along the cracks is due to bat excreta.

We walked along the river while waiting for the bats to emerge on their foraging flight, and I found a dead one on the sidewalk. You can clearly see the free tail; the tail of other bat species lies within the membrane that runs between their hind legs.

At last, just as predicted by the local news and hoteliers, the bats began to emerge from the far end of the bridge across the river, and then in successive waves from each of the slots along the underside of the bridge. They flew in a straight line down-river, with the entire emergence probably taking about 15-20 minutes.

According to Wikipedia, this mob consumes 10,000 to 30,000 pounds of insects EACH night.
After this excitement, we had to retreat to a hotel and drink about a gallon of water to rehydrate. I can't imagine what the air quality inside those roosts is like with a million and a half hot little bats heating up the enclosed space and producing great quantities of ammonia as they digest their evening meals.