Sunday, March 21, 2010

Great Swamp Herpefauna

I was at the Great Swamp NWR yesterday in search of early spring migratory birds. I saw my first returning Eastern Phoebe of spring migration. (I did see an overwintering phoebe during the C&O Canal Count in January). Waterfowl were in low numbers, but there was a diverse mix of species visible from the blinds. I enjoyed hearing a pair of Red-shouldered Hawks as well.

However, reptiles and amphibians were far more noticeable than birds. Lots of Spring Peepers were evident around the swamp. I saw none but heard their peeping calls. In addition to the peeping, I heard some rising trills that I could not quite place. It was similar to the call of Gray Treefrogs, except that the audio samples I have heard of that species are of trills on an even pitch rather than a rising one.  

Update: I now think that the trills were from New Jersey Chorus Frogs. Both New Jersey Chorus Frogs and the similar Upland Chorus Frogs occur in Morris County, but New Jersey Chorus Frog is more likely to be encountered in the Great Swamp according to the refuge's herp list.

Another frog species present was Wood Frog (one is shown above). These frogs were calling in groups in several shallow ponds along the boardwalk trails. Wood Frogs have already laid a lot of eggs, as evidenced from the many egg masses, but are still very actively courting and mating.

In addition to the frogs, many snakes were active. Most of the ones I saw were taking advantage of the warm day and sunning themselves. I saw two Garter Snakes, neither of which was in a good spot for me to photograph it. The Northern Water Snake below was both photogenic and cooperative, as it stayed in the same position despite much activity on the boardwalk nearby.

This snake was sunning on a branch over the pool where I photographed the Wood Frogs. Water snakes prey on frogs, among other things. As I photographed the snake and listened to the frogs, I was reminded of a series of photos taken by one of my Flickr contacts of a water snake eating a bullfrog. The rest of the series is in the same set.