Hybrid Birder: Wood Frogs in a Breeding Frenzy

Sunday, April 10, 2011

Wood Frogs in a Breeding Frenzy

Wood Frog Air Sacs

After the big thunderstorms last night, I hoped the rain would hold off today so I could check out the vernal ponds on the Chippewa River State Trail - where I spotted Wood Frogs in amplexus last March. When I left the house around 11am, the sky was overcast and threatening, and the temperature had climbed up into the 60s.

Would the Wood Frogs be a quackin' today?

I parked the Prius on County M and walked up-river to the trail marker at Mile 26.

I've read that you can hear some frog calls from a mile away, but not today. I was about 100 yards from the ponds before I heard the springtime noise made by boys: a chorus of loud raspy quacks (Wood Frogs) interspersed with a few peep-peep-peeps (Spring Peepers) and an occasional trill (Western Chorus Frogs).

The pool was full of hundreds of Wood Frogs. I scanned the water but I couldn't see them - at first. The light was harsh and every time a cyclist rode by, the pond went silent. I waited and waited. Then they started up again. Floating on the surface of the pools, Wood Frogs are relatively easy to spot. So I focused on them.

Wood Frog in Duckweed

Wood Frog Inflating Air Sacs

It was mesmerizing. Frogs chasing each other in a shallow vernal pond. Splashing, sinking, swimming and quacking.

After sitting for an hour or so, I walked further down the trail, hoping to spot a Chorus Frog or a Spring Peeper. I could hear them, loud and clear... but I still couldn't see them.

Then a frothing ball of Wood Frogs caught my attention. It looked like they were all hanging on to one frog, who seemed to be drowning or dead. I tossed a pebble at them, but they did not disburse. What is going on here?

Five Wood Frogs in a Ball

When I got home, I "googled" Wood Frogs. "Breeding can be stressful for females; plagued with the weight of multiple competing males, some females drown." That's seriously stressful.

Another interesting fact: Females lay only one egg mass. Count the number of egg masses in a vernal pool and you get a good estimate of female numbers.

On the way back to my Prius... I spotted three "first-of-the-year" birds and one wildflower: Rusty Blackbird, Ruby-crowned Kinglet, Field Sparrow and Bloodroot.