Monday, March 16, 2009

Emerging Frogs

This weekend's mild weather has put the wheels of spring in motion. According to the calendar, spring begins this Friday, May 20th. But nature has no plans on waiting for next friday. The purple sheaths of the Skunk Cabbage's flowers are emerging from damp soils near Bechtel Lake. Tufted Titmice have become increasingly vocal and territorial. I saw my first Eastern Bluebird of the spring behind the cottage this past week as well.

One of the surest signs of spring is the chorus of frog calls that ring out from our swamps, marshes, vernal pools, ponds, and lakes. Saturday evening I was out for a walk to check on the status of the vernal pool located on top of the Wood Thrush trail. The size of this body of water varies from year to year depending on the amount of winter snowfall and spring rains that fill this small depression in the earth. Upon reaching the pool I was pleasantly suprised with the amount of water. More water equals more success for the amphibians planning on breeding in this relatively temporary body of water. In dry seasons, the pool dries up, leaving any undeveloped amphibian larvae unable to complete their metamorphosis.

On my way back down the hill, as the sun began to fall behind the hills, I heard a couple of hardy spring peepers calling out into the evening air. Though these frogs are quite small, one peeper can produce an ear-ringing song. Much of their vocal prowess is due to the ballon-like throated from which the sound originates. As you can see from the photo above, a calling spring peeper seemingly increases its overall size by 25% when its throat is fully expanded. Peepers calling in the evening and night hours to remain out of sight of potential predators. This sort of activity could get a frog eaten if done during the daylight hours.

Another common, but often overlooked, frog breeding in the cool temperatures of early spring are the wood frogs. This species is a bit larger than the peepers, but their calls are less obvious, especially when both species are breeding in the same body of water. The wood frog (photo right) is especially fond of vernal pools. If found in good numbers, a collection of breeding wood frogs sounds like a bunch of ducks quacking with sore throats. These guys leave copious amounts of eggs attached to submerged sticks along the edges of the vernal pools. This frogs can often be spotted in the daytime hiding in the water if you look closely. Their breeding behavior is much easier to observe than the spring peepers.

Soon to come, after the first warm spring rains, will be the emergence of our local breeding salamanders, followed by the pickeral frogs, toads, green frogs, bullfrogs, and grey treefrogs. If you'd like to learn more about these animals, please join us this spring for one of our spring hikes or amphibian walks.

-Adam Zorn, Naturalist


Kim said...

Hey guys, nice work! Love this page!I have a few ques for you...what are the insects that are emerging by the millions in snow and on leaf litter, they are teeny and almost look like thrips? Do Soldier Beetles overwinter on Tulip Trees? I've seen a ton on a few trees on the trails here at BMR. Finally, did you like the jam??? :9 ps my Dad saw 6 Pilated Woodpeckers at his house going nuts the other day! Enjoy!

Westmoreland Sanctuary said...

Kim: The little insects on the leaf litter and snow are likely snow fleas, a type of springtail. It is possible that the soldier beetles overwinter in the deep grooves of large tulip trees. As adults they also eat nectar. Many trees like tulips and maples will leak sap from wounds sustained during the winter, and the beetles can be attracted to that too(eg. we have tons of bugs visiting our sap buckets and spiles). The jam is good! -Adam