Sunday, May 1, 2011

Confused About the Season

Although I am a little confused about the season, I cannot imagine what it would be like to be a frog during the recent winter-to-spring-to-winter flips. By the end of last week three species were calling - chorus frogs, spring peepers, and wood frogs. On Friday afternoon, I saw (and heard) around 100 wood frogs calling in a pond in Hartley Park, along with many egg masses and several females.

Four male wood frogs calling in vicinity of multiple egg masses, with a pair in amplexus in the middle
male before calling

Wood frogs are fun to watch calling.

swimming while calling
after calling

female wood frog on edge of wetland
The colder weather this weekend has quieted the calling, but these three species should be out again as it warms up over the week.

Why it would be hard to be a frog in this weather:
Male wood frogs must be almost out of energy after 3 weeks of starting and stopping calling. These early season breeders emerge from winter hibernation soon after the snow melts and the males begin calling almost immediately, fueled by fat storage from last fall. Calling is the most demanding activity that many male frogs will ever do; in some species, calling is 10 times more metabolically demanding than moving at maximum speed. The trunk muscles, which power calling, can be 12% of body mass in a male frog, while only 3% in a female. Not only is calling a lot of work, males of early breeding species expend all that energy before spending much (or any) time foraging for food.

I learned most of this from a great (but heavy) book:
The Ecology and Behavior of Amphibians - Kentwood D. Wells

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