Basking Sites at a Premium, Amphibs Exploit the Season

gd_3_1_09ybtuBy the end of the first week of this period the Wetland’s turtles, frogs, and toads were out in numbers. Yellow-bellied Turtles and Painted Turtles were basking on logs, rocks and any other object projecting from the water, with little room to spare. The young Yellow-bellied Turtle in the image at left (perhaps a two-year-old) was lucky enough to find a perch all to itself on a piece of flotsam too small for other, larger turtles to climb onto.

The first Snapping Turtles of the season appeared on March 8 as one large individual was seen foraging in the shallow water on the north side of the Wetlands and another much smaller member of the species was seen near the Wetlands Overlook. A large snapper was seen basking on one of the stumps in the open water of the Wetlands on the ninth day of the month.

American Toads have been calling continuously from the water near the smaller of the two Wetlands Overlooks, on the north side of the Wetlands. Although most of the toad activity had been concentrated in the northeast corner of the Wetlands, their loud, musical trill could be heard throughout. The toads were mating. One pair was seen mating in the U-shaped pond at Flap the Wings next to the Ornithopter, with long strings of eggs trailing behind the busied duo. Several of these strings of eggs were seen in the pond, presumably produced by this pair. Keep in mind, one female American Toad can lay as many as 6,000 eggs in a season. That’s a lot of eggs!

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gd_3_1_09upchUpland Chorus Frogs, Spring Peepers, Pickerel Frogs, and Bullfrogs were also out in force. Pickerel Frogs seemed to be concentrated in the northwest corner of the Wetlands, although it may have been that their low, snore-like calls were not as obvious in other parts of the Wetlands, being drowned out by the much louder toads. However, I did have better luck actually seeing Pickerel Frogs (many of them) among the willows, and in the grass, at the northwest corner of the Wetlands.

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Bullfrogs breed throughout the warm months. I’ve yet to hear their deep, throaty calls in the Wetlands this season. No need to rush things, they have all summer to breed. The other four amphibians mentioned above are strictly late winter to early spring breeders, and there’s an urgency to their activities. Why breed so early in the season, and what’s the hurry? Perhaps they get a jump on the other frogs and toads in our area (nine other species have been documented in the Wetlands) by breeding early in the season at a time when spring rains assure that there will be enough water for them to breed in. The species that are currently breeding have a relatively short life cycle. From egg to adult frog (or toad) is often only a few months’ time. These frogs and toads have to find a mate, lay eggs, and the tadpoles that hatch from the eggs have to metamorphose into frogs (or toads) all before the ephemeral pools of water that they tend to breed in dry up for the summer, which is often the case. So, it’s to their advantage to get it done quickly. Their adult lives are most often spent away from water.

Another advantage to breeding early in the season may be that there are fewer snakes about in late winter and early spring; I haven’t seen a water snake in the Wetlands yet this season. Given the large number of frogs and toads presently milling about in the water, their frog and toad minds focused on little more than procreation, a snake would do well at this time of year.

The frogs and toads must, nonetheless, be wary of predators. On one occasion, I noticed a Red-shouldered Hawk perched in a tree just above the point of heaviest toad activity in the Wetlands, the hawk’s eyes trained on the frenzied movement below. I think, though, that the hawk would be wise to devote its efforts to the capture of Bullfrogs instead: toads secrete a poison from their warts and parotoid glands (the large bumps behind each eye) which is reported to be unpalatable to those that would eat the toads. Perhaps that’s why there was a partially eaten toad floating in the water at that location later the same day.

Pickerel Frog’s skin also secretes a toxic substance which may make them unappetizing to predators. Both the American Toad’s and Pickerel Frog’s distasteful condition may help to explain why the Red-shouldered Hawks, who had spent a good part of the winter months fishing Bullfrogs out of the swamp across from the main Wetlands Overlook, are not helping themselves to the apparent amphibian buffet currently laid out before them. I’ve only seen the Red-shouldered Hawk hunting in the Wetlands on one occasion since the amphibian breeding season began.

The breeding frenzy nearly came to a halt with the coming of the relatively cool rains of the last several days of this period.

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