Friday, July 14, 2006

Amphibia, Etcetera

Sorry. No exciting news about Ivory-billed Woodpeckers here. This week my days off were consumed with tedious yard work and a major painting project. Not the way I wanted to spend my time, but there you are. No adventures in the swamp, no bark scaling or mysterious holes in trees, no tantalizing encounters with Pileateds, not even an intriguing double-knocky sound. Nada.

My riding mower hasn't been the same since I whacked it into an exposed tree root last year. Ever since then the blade hasn't cut evenly, creating what look like crop circles. This week it died, and decided to do so in a most inopportune location. With the rear wheels locked up I had to drag/push it all the way from the house back to the garage for proper internment. A hot sweaty miserable job. Of course the immediate problem still remained. The lawn demanded mowing, more so because I had put it off for weeks. So yesterday I went out and bought a push mower. Worked like a charm! Cut the grass and no crop circles.

While mowing I scared up yet another Southern Leopard Frog. Very pretty as frogs go. Unfortunately one didn't hop out of the path of the mower. Blade and frog intersected. The mower won. Results were messy.

While I'm on herps, I recently read in an AP News article that Mediterranean Geckos are now found as far north as Kansas. Is this more evidence of global warming, or just another example of a non-native species that has been very successful? In my old copy of A Field Guide to Reptiles and Amphibians of Eastern/Central North America (1975 edition) it states that "the speed with which this gecko has expanded its range in the southern U.S. in recent years is even more remarkable than the spread of the cattle egret." The outdated range map in the book indicates that the gecko was then distributed across South Texas, with scattered populations in East Texas, Louisiana, and Florida. Looking at the 1998 edition it appears that the gecko's range had continued to expand, with populations as far north as central Oklahoma.

Mediterranean Geckos are nocturnal. At night they crawl over the walls and windows of our house, and it's not unusual to see a dozen or more around our porch on a warm evening. We have to be careful when opening the doors at night lest one of them tries to wriggle inside. Same goes for Gray and Green Treefrogs, which are similarly fond of door sitting.

Ever since I moved here I have been puzzled by one of the common nighttime sounds that I hear coming from leafy places around my yard. I've also heard this sound at my friend's house in Spring, which is just north of Houston. I would describe it as a series of chirps or clicks, and for a long time I figured it was probably some kind of insect. There are tropical frogs that tink and click and chirp, but from the range maps in my books it didn't look like any occur this far north. Then I read that Mediterranean Geckos will emit squeaks and clicks, and because I had seen geckos while searching for the source of the clicking I concluded that I had finally solved the mystery.

But I was wrong. I described the sound I'd been hearing to John Arvin, and he told me that what I'd heard was the Rio Grande Chirping Frog, a species which has undergone a range expansion similar to that of the Mediterranean Gecko. A little online research verified that despite my outdated range maps the Rio Grande Chirping Frog has spread to Southeast Texas. Click here to hear one chirping.

There's a lesson here somewhere. Wildlife populations are dynamic and subject to change. Range maps are valuable tools, but can't be taken as gospel. Even creatures without wings, such as geckos and frogs, can undergo rapid range expansions. With birds the power of flight can accelerate things. In 1987 I saw Eurasian Collared-Doves in the Florida Keys. At that time the species had only recently arrived in the U.S., and was just beginning it's dramatic North American range expansion. Back then you had to go to southern Florida to see one. It took less than twenty years for the species to spread across the continent to California. Here in Texas they are quite common. I have yet to get one for my yard list, but it's only a matter of time. They are plentiful in Beaumont, a short distance to the south, and lately I've been seeing them in Lumberton, which is just north of us.

Monday, July 03, 2006

The Search Continues...

On Thursday, June 29th, Don and I did some more exploring in the Jack Gore Baygall Unit of the Big Thicket Preserve. According to Don we are the only volunteers actively involved in this project at present. My work schedule doesn't allow me to spend much time in the field, but unlike most of the weekend warriors that attended the orientation meeting I live relatively close to the Big Thicket and don't have to travel very far.

Don wanted to check out an area on the northwest boundary of the Jack Gore Baygall Unit. We followed a rough ATV track to a park service picnic area near the Tater Patch (incorrectly labelled Potato Patch on park maps). The “road” was narrow with dense brush pressing in, but Don didn’t seem to mind the branches scraping the sides of his truck. I wouldn’t have driven my vehicle in there – I value the paint too much. This “road” ends in a cypress swamp, at the edge of a large expanse of protected bottomland forest that extends east to the Neches River. Because of information that Don had received from locals we were interested in exploring this area, but access was difficult. First we had to cross a muddy baygall and then find a way across Black Creek. Because of recent rains the creek was up. Rather than attempt a crossing we just bushwhacked north along the edge of the swamp. We saw some nice habitat with big old trees. Noticed a few tall cypresses riddled with woodpecker holes (Pileated, from the look of them), but again found no evidence - auditory, visual, or forensic – of there being Ivory-bills present.

Don is a volunteer in the Big Thicket Preserve, and his days are divided between bird banding and searching for Ivory-bills. He’s done much more exploring than I have, and is more optimistic about the possibility of the species persisting in the Big Thicket. He’s been talking with local people who claim to have seen Ivory-bills in the past. From these conversations he’s concluded that an area of high priority is the north end of the Jack Gore Baygall Unit (which extends considerably farther north than indicated on the park map). Don has received permission to go onto some of the private land outside the preserve in this area.

When I’m birding with Don I try not to be too discouraging, but I’m really pessimistic about our chances of finding anything. I also doubt the ability of local property owners and hunters to differentiate between a Pileated and an Ivory-bill. These people aren’t birders. They haven’t documented their purported sightings. Among birders it is generally accepted that identifications of rarities will be questioned and even challenged, but outside the ornithological community this sort of inquiry can come across as rude, and tends to make people defensive. So rather than potentially antagonize anyone, the claimed sightings go unexamined. About a report of Ivory-bills nesting several years ago near the Tater Patch, all I know is that the observer was able to distinguish the birds from “indian hens,” a colloquial name for the Pileated Woodpecker. Not knowing the Pileated Woodpecker by its common name doesn’t inspire much confidence in the identification.

If there are Ivory-bills in this area, finding them is bound to be very difficult. To start with, aside from Timber Slough Road there aren’t any proper roads or trails. Streams and baygalls are frequent obstacles. The vegetation can be almost impenetrable (there’s a reason why they call it the Big Thicket!), and in the aftermath of Hurricane Rita there’s fallen timber everywhere. I wouldn't go in there without a compass or GPS. It would be very easy to get lost.

I always carry my digital camera with me, but as Don has pointed out, even if the bird still exists, getting a photo of one would be extraordinarily difficult. In forest like this it’s hard to get a decent view of a bird unless it’s reasonably close. You hear many more birds than you actually see. Pileated Woodpeckers are frequently heard but seldom seen, and getting a good photo of one would be a real challenge. Assuming Ivory-bills to be every bit as wary as Pileated Woodpeckers and much rarer, unless you knew the location of a nest or roost hole, getting a photo would be next to impossible.

Here’s an odd coincidence. At the Tater Patch I photographed a Southern Leopard Frog. It was a new amphibian for me. When I got back home later that day I was surprised to find another Southern Leopard Frog sitting at my front door. I’d never seen one before, and then I see two on the same day, many miles apart! Here's a photo of the one I saw in the Tater Patch.And here's the one I found back at our house. Looks like it has a piece of a plant stem stuck to its head.After having a look at the Tater Patch we spent some time along Timber Slough Road. Don showed me where he had heard a series of double raps...only to discover that the bird making the sounds was a Pileated Woodpecker. Our best bird sighting there was a singing male American Redstart. It was hot but we walked as far as the river, where we saw 3-4 Mississippi Kites soaring. Only one other vehicle passed us on the road.