The Nature Writers of Texas

The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Saturday, March 03, 2007

Frogs Are Getting Lots of Attention
by Ro Wauer

During the last few weeks there have been numerous newspaper articles and comments by media personalities regarding the declining frog populations all across the world. However, herpetologists, scientists who study amphibians and reptiles, have written about those very same concerns for several years, and the vast majority of those individuals have blamed the decline on both loss of pertinent habitats and global warming. I remember my brother, who is an amateur herpetologist, telling me about the loss of frogs in California, especially in Yosemite National Park and the San Francisco Bay Area, 15 - 20 years ago. He pointed out that such declines were a significant warning about the declining stability of our natural world. Now that this issue has hit the headlines, maybe it will provide one more bit of evidence that something must be done to reverse that trend.

With that said, I thought it might be appropriate to access our local frog population. After all, the Golden Crescent has six species, and at least four of those have been reasonably common, at least in my yard, over the last several years. The most numerous of those is the southern leopard frog, a medium-sized frog with leopard-like black spots and pale sidelines against a green background and a pointed snout. The Rio Grande leopard frog, a paler version of the southern species, also occurs in the southern portion of our region. Leopard frogs can occur almost anywhere there is sufficient moisture, even where there is only a birdbath at ground level. From all that I have observed, leopard frog populations have remained stable.

The largest frog in our area and throughout all the eastern two-thirds of Texas is the bullfrog. It can be abundant in large ponds and slow-flowing streams. This species has a brownish back, greenish head, a noticeably large eardrum, and a rounded snout. This is the frog that has a deep bass voice that has been described as "jug-o-rum" in Roger Conant and Joseph Collins' excellent book, Reptiles and Amphibians Eastern/Central North America, a Peterson Field Guide.

We have three treefrogs in our area: green, gray and squirrel. Green and gray treefrogs are reasonably common, while squirrel treefrogs, at least in my yard, are not as numerous as they once were. All three of these frogs are smaller than leopard frogs, and each possess adhesive discs at the end of their toes. They therefore are able to climb onto trees and shrubs and up walls and even glass panes. Another interesting characteristic of treefrogs is their ability to change color, depending upon their substrate. But basically, green treefrogs are usually bright green and with a yellowish side stripe from just below the eye to their flank.

Gray treefrogs are multicolored with gray blotches, usually outlined in black, against a paler background. A major feature is a light spot below each eye, and the undersurface of the legs is orange or yellowish. The call of the gray treefrog has been described as a musical, flutelike trill, not too unlike the call of a red-bellied woodpecker. The call of the green treefrog is more bell-like and its call has been expressed as "queenk-queenk-queenk," with a nasal inflection. They may repeat their calls as many as 75 times a minute, according to Conant and Collins.

Squirrel treefrogs are the smallest of the three, and can be green to brown, but with a short darker line running from the snout through the eye to near the leg and sometimes onto the belly. It has been called "rain frog" in some parts of the South, due its habitat of falling out of trees during hot pursuit of prey. The squirrel treefrog's voice is ducklike, but more nasal. It has been described as a harsh trill repeated 15 to 20 times in 10 seconds, according to Conant and Collins.

There are four additional frogs that have been recorded within the Golden Crescent, the upland, spotted, and Strecker's chorus frogs, and Blanchard's cricket frog. These little frogs are fairly similar in appearance, and readers wishing to identify them need to utilize plate 46 in the Conant and Collins field guide.

All the frogs, whether in South Texas or elsewhere in the world, are extremely sensitive to toxic substances in the air and water. They truly are like caged canaries that are carried by miners underground as an early warning system. We need to take heed!

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