Friday, April 22, 2011

Wood Frogs!

The wood frogs are calling in Duluth - Yesterday, I heard wood frogs calling in small wetlands in and near Hartley Park.  Most of the wood frog activity was in ponds that are shallow and have solar exposure.  These ponds are likely warmer than deeper or completely shaded wetlands. 

I even found wood frog eggs in two ponds.  Wood frogs are probably still in the midst of breeding as many of the ponds I visited yesterday did not have eggs. 

Wood frogs are explosive communal breeders, meaning that breeding occurs over just a few days and all (or most) of the eggs are laid in one location in a pond.  Eggs are generally attached to submerged vegetation near the water surface in open areas of a pond that are fairly shallow (1-2 feet).  When first laid, wood frog eggs are very easy to spot.

30+ wood frog egg masses (each female lays one egg mass consisting of hundreds of eggs)
Up close, it is easy to see the embryos through the clear protective gelatin-like layers.  This allows us to track development before the eggs hatch, which occurs in 4 to 28 days depending on conditions.
recently laid wood frog eggs masses
  ***Note: If you find wood frog eggs, please leave them undisturbed in the water. 


  1. I've been hearing chorus frogs and wood frogs by my home near the airport for the last week or so. No spring peepers yet. I'm excited to identify the eggs now that I know what they look like!

    I did hear spring peepers mixed in with the chorus and wood frogs at a pond north of Duluth in the last few days.

    Thanks for a great blog! The video on how wood frogs spend the winter is awesome!

  2. Thanks for the update on hearing chorus frogs. Next we should start hearing spring peepers. I would love to know if anyone hears leopard frogs in or around Duluth - they would be the next frogs to start calling after spring peepers.