Amphibians on the March – in February!

2012 MIGRATION SEASON BEGINS

by MacKenzie Hall, Biologist

Jefferson salamander - Bob Hamilton
A Jefferson salamander gets an early start on spring (Feb 24). Photo by Bob Hamilton

After the wimpy winter (which I quite enjoyed), we knew the amphibian migration could start a little earlier than normal this season.  The ground has been thawed since mid-February across most of NJ, leaving only a reasonably warm nighttime rain to propel frogs and salamanders into their annual breeding frenzy.

And in an oddly symbiotic way, their frenzy becomes ours as well.  This year, the Amphibian Crossing Project covers 6 road rescue sites in Warren, Sussex, and Passaic Counties – more than we’ve ever done before – and includes monitoring at a number of amphibian road-crossings in the Sourland Mountains region.  More than 130 trained volunteers are part of the migration survey, which aims to 1) help amphibians survive the dangerous cross-road journey to their breeding pools, and 2) collect data to find out which sites are most important and which populations are most threatened by traffic.  With all the new sites, new helpers, and big plans for the data we collect this year (stay tuned…), a lot is riding on the weather.  We and our scouts have been out in every little nighttime rainfall over the past month that’s been anywhere near 40 degrees.

Gene & Ginger
New volunteers Gene & Ginger Martel show that they're ready for migration! Photo by Ginger Martel

My first salamander of the season came out of the woods at 2:00 am on February 24th at a crossing in southern Sussex County, as light rain turned to snow in 37 degree air.  Aside from the three bulky humans watching him labor across the road, this Jefferson salamander had a quiet and uneventful trip.  No cars passed through; the only thing coming down on his cool skin was the occasional snowflake.  If you’re a slow, small amphibian, a middle-of-the-night migration is the way to go.  Your chance of survival is slim in the earlier evening’s traffic.

The nights of February 24th, 29th, and March 2nd were also rainy and just warm enough to draw some eager amphibians to the surface.   Jefferson salamanders are famously cold-hardy and have made a big push to their pools.  Spotted salamanders, wood frogs, and even a few spring peepers have taken advantage of the early thaw as well.  Peak migration is still ahead of us in northern NJ, though, so we’ll continue watching the weather and waiting for our next night out in the rain.

Spotted female
A large female spotted salamander, heavy with eggs, gets help crossing a Hunterdon County road (Feb 29). Photo by MacKenzie Hall