A Tiny Tragedy

 Stella, looking round...

My spring obligations began to close in, and I was trying to see into the future and predict when the batgirls might be ready for release. I understood from Rob Mies and Lisa Fosco that bats should be able to fly continuously for ten minutes in an enclosed space to be considered releasable. I watched my girls flutter languidly from one perch to the next and wondered if they’d ever get there. But they still had weight to lose, so I worked them and kept their rations slim (12 mealworms each day) and kept hope alive. What I didn’t want to do was to have to send them to the Ohio Wildlife Center for safekeeping while we were in Alaska from May 14-21. I desperately wanted to release them before I left. I knew from past experience that the stress of transport and of being in a new environment, which would likely be much less bat-friendly than our quiet garage with its spacious flight tent, might throw them off their feed and cause them to go back into torpor. These bats knew me and were comfortable with being handled by me. Heck, sometimes I had a hard time getting them to fly--they liked hanging out on my gloved hand. I liked it, too. But oh, I wanted them to go free.

The other wall facing me was the possibility that one or both of these girls was pregnant. Big brown bats  mate in the fall and delay implantation of the fertilized egg until conditions are right. They deliver their young—one or sometimes twins—from mid-May through June in Ohio. What I did not want was more bats to worry about. 

Lisa Fosco learned that through hard experience, when bats would deliver babies while still in captivity. She said she released a female bat with a young baby clinging to her only to see the baby fall to the ground, its newly released mother vanishing into the sky.  Ack ack ack. The only alternative to prevent such a boondoggle, she said, is to keep the mother and baby together in confinement until the baby is flying and completely independent. My mind boggled at the prospect. How many more months would that be? How could I provide adequate nutrition for a lactating mother bat, and how could the baby bat learn to forage in a flight tent? No, no, no, no. These bats had to go and find a maternity roost before they delivered their young. I felt like Indiana Jones in the vault with all four walls closing in. 

On the evening of May 1 I went out to fly the girls and found a small red wad on the towel beneath the bats’ roost. I knew what it had to be before I picked it up. It wasn’t a wad, it was a being: a fetus, about half developed, its tiny wings wrapped around it, each minuscule toe perfectly formed, its face dished like that of a puppy, its eyes just dark spots between the clear fetal skin. 

 

I turned it over and over, unfolded its wings and worked its tiny feet. It would have been a boy. I studied the quiet bats. Stella hung alone in the corner, not cuddled up to Mirabel as usual. Gently I picked her up and found the birth blood on her.  I fed her all the mealworms she wanted and gave her a dropper of water, apologizing to her for failing to get her out to a maternity roost where she could deliver in safety. I didn’t fly her for the next two days. By the next morning she’d passed the afterbirth. 

Looking at her baby's perfect spine reminded me of the early sonograms of our kids, just notions in the womb, but already adorned with a string of vertebral pearls. 

Oh, so very sad to know this one would never fly.

There was a bright spot in the sadness. Both bats, by May 2, were down to 20 gm, which was finally in the normal range. Yet they were still not showing sustained flight. My hands were tied. I felt the pressure of time once again. My heart ached to see the girls fly free.

Most of all, I ached for Stella and her lost baby. I wept for him and for her. I hoped that I could do better by Mirabel, hoped that part of her stubborn weight was a little fetus hanging in there, waiting for her to find the right old attic in Marietta where it could come into the world as nature intended.

I knew we were on the road to release, knew all these bats needed was a little more time. And time was the one thing I didn't have.

Bat Boot Camp

At the beginning of their training, I had to pick each bat up as if it were a box turtle--from above. If I let the bat climb onto and cling to my glove, I'd never get it in the air--they stuck to me like Velcro. I'd pick a bat up like you'd pick up a biscuit, swing it a couple of times, then gently toss it into the air. It would catch itself with its wings, flutter to the nearest tent wall, and cling. Well, it was better than not flying at all.

Stella, large and in charge.

 What I didn't know at first is that bats need to be warm--really warm--to be able to fly. They need to be slim enough to fly, but they also have to be warm. Every once in awhile I'd feel a wing or tail against my bare skin and be shocked at how cold those membranes were. Mid-April is still pretty darn cold, with nights barely edging into the 50's. And bats like to fly when nights are in the 60's and warmer. So as I think back on it, I may have been pushing these animals to fly in mid-April when they were physiologically incapable. It was probably not just that they were too fat. They were too cold to fly.

As I thought about it more, and conferred with Rob Mies and Lisa Fosco, it hit me that bats who have been hibernating all winter basically wake up and, without any conditioning at all, take to the wing. They fly out and catch a meal of moths. They aren't fat at that point--they're running very lean after a long winter. But by some miracle their muscles don't atrophy and they're good to go on their first flight. If I laid up for  six months, I wouldn't be able to hobble, much less catch a moth in flight. 

So maybe I was asking too much. I laid back a bit on the flight conditioning. We still worked out each evening if it was 55 or above, but not as hard. I noticed that they flew MUCH better when the day had been warm and the garage had heated up. Once again, the bats told me what to do and what not to do.

I kept them at 12-15 mealworms each per day, and they lost weight nicely, slowly but surely. 

I wish someone would keep me to 12 mealworms per day. Or the equivalent.

In the Bat Tent

I've left you with the post "Fat Bats" for a week now. I've been busy doing all the things that don't get done when you're running around Alaska looking at moose and orcas. Spent much of the last two days washing orchids. I find I have to wash them a couple of times a year, scrub out all their humidity trays and most of all comb each one over for that nasty white Boisduval scale and regular scale. It does wonders for them, washing orchids. Take a look at yours. Are their leaves caked with dust? Well,take 'em in the shower and give those plants a good hard rinse with tepid water. They'll thank you for it.

Bats. When we last saw Mirabel and Stella, they were topping 25 gm. and unable to fly worth a nickel, certainly unable to catch their own food on the wing. In early April, I ordered the Zephyr Screen Gazebo by Wenzel. It’s made of super-soft polyester mesh and silky nylon fabric, and I didn’t see any way they could hurt themselves on that. Most importantly, it was fitted with tight-closing zippers and a welded nylon floor integral to the tent, which is designed to keep bugs off your picnic table, but also to thwart my hairy little Houdinis. A bat can get out of a ½” crack, and it will find that crack before you know it. They needed to be completely enclosed.

Zephyr is a good name for this tent because the slightest breeze will crumple it up and roll it across your yard. The steel poles are about the thickness of a good asparagus spear. Please. Sooo flimsy.  I don't recommend it for outdoor use at all; I can't imagine where you could put this up and not have it destroyed within a week by a good gust of wind. So I ditched my plans to erect the tent in the yard, and decided to set it up in our detached garage. Our cars could live outside for a month. This decision turned out to be a bit of genius. I didn't have to worry about inclement weather or raccoons, although I did say a frequent prayer that the black rat snakes in our garage wouldn't figure out how to open the zippers. Needless to say I was completely OCD about keeping all the zippers closed. What I did not want was to feed my miracle girls to the snakes.

I released the batgirls into their spacious tent on April 14, and was disappointed to find them uninterested in using it at all. They'd flutter down to the floor and hop along. They'd never be able to use the clever bat roost I'd devised out of a stepladder and some bathmats.  Once down, they'd never fly back up there.

So I took an old crate and a towel and made a little roost on the floor of the tent, one they could literally walk to. This conditioning thing was going to be a lot more work than I thought. Egad.

I sought advice from Lisa Fosco of the Ohio Wildlife Center. She confirmed my suspicion that a 25 gm. bat is too fat to fly. And she added a warning: Sometimes, despite a rehabilitator's best efforts to condition a fat bat, it will fail to lose the weight. "And THEN what??" I asked, horrified. "Well, then it has to be taken into permanent captivity. It's happened to me twice. I worked them and worked them and they just never dropped the weight."

Lisa warned that I had to keep the bats eating; that when I cut their rations to six mealworms apiece each day, they'd try to go back into torpor, and lose no more weight. "Keep them eating, keep them active," she said.

And Mirabel stopped eating. She wouldn't eat for a week, but she still didn't lose a gram. Uh oh. I racked my brains. What to do?? How do you force-feed a bat? Finally I decided to offer her a couple of droppers of the liquid nutritional supplement Ensure, which she eagerly drank. And the next evening she started eating again. Whew! 

I watched the bats. They were so ravenous when I’d feed them, always looking for more worms. I reasoned that since I was "flying" them each evening, they could probably stand to eat more than six worms a day. I doubled their allotment. And against all expectation, that was when they began to lose weight. It seemed counterintuitive for them to drop weight when they were eating more, but it was working. I was a few days into this new protocol when Rob Mies emailed.

“Our lead keeper and I just talked and think you

should try giving them 12 mealworms each daily and see how they do in

a month or so.  We think their bodies may be shutting down fat

consumption because food has dwindled, but if they get used to 12

mealworms it should start to fall off.  Let me know how it goes.”

I felt like I did when I was raising four ruby-throated hummingbird nestlings and I started to worry that the soy-based adult maintenance formula I was feeding them was insufficient for their needs, growing so fast and making all those feathers. I decided to squeeze out the innards of mealworms like toothpaste and gave it to them on the round end of a blunt toothpick along with their nectar diet. Within hours I could literally see them pick up and begin to thrive. They all went on to fledge. A year later I learned from an experienced hummingbird rehabilitator that they probably wouldn’t have survived on maintenance formula alone—the soy protein settles out of the nectar and is indeed inadequate for a growing baby’s metabolic needs.

Once again, Instinct had stepped in and told me what to do. The bats had told me what to do.

Look at this photo. Isn't it weird? My little ectomorphic children, dwarfed by a giant bat. Eeee!