The Herrontown Amphibian Report: 2026

The eggs are laid in the vernal pools. The frogs and salamanders have scattered into the nearby woods. They migrated later than usual this year, delayed first by snow drifts that lined the road where they normally cross to reach their vernal pools. But the snow melted and along came a few relatively warm, rainy nights to lubricate their movement across the road and through the forest.

Long before the annual spring migration of woodfrogs, spring peepers, and spotted salamanders began, the weather was being closely watched by the Princeton Salamander Crossing Brigade, a group founded by Inge Regan, a board member with the Friends of Herrontown Woods. Volunteers attend late-winter training sessions at the Sourlands and elsewhere, then benefit from the expertise of Brigade members Mark Manning, Fairfax Hutter, Lisa Boulanger, and Mark Eastburn.

The work of the Salamander Brigade, now in its fourth year of helping amphibians safely cross the road, was greatly helped by a collaboration this year with the Princeton Police Department, which has placed blockades across the road during rainy nights. The blockades reduced car traffic almost to zero, allowing the vast majority of amphibians to safely cross the road. 

As described in some excellent CBS News coverage earlier this week, traffic in previous years led to the loss of up to 40% of the amphibians, despite the valiant efforts of the Brigade to help them across.

This year, Brigade members met at dusk on four different nights, in raincoats and reflective vests, with powerful flashlights to monitor and document the migration. 

Those who had never held a salamander got the joy of doing so.

It's not always easy to take notes on weather and amphibian numbers out on a roadside in the rain. It helps that Dr. Regan has long experience writing up charts for patients. The data gets sent to the Sourlands Conservancy, then on to the state wildlife agency. 

Over four evenings, volunteers counted 40 spotted salamanders, 7 woodfrogs, and 52 spring peepers. 

Those raucous spring peepers you hear in spring are incredibly tiny.

The spring peepers seem to be doing okay, but the low number of woodfrogs is concerning. Last year there were dramatically fewer woodfrog egg masses in the main vernal pool in Herrontown Woods, and this year again they are greatly reduced. In June last year, there was a mass dieoff of tadpoles in another pool. A Rutgers professor studying wildlife diseases said ranavirus has been hitting some populations in NJ. 

That pool, not far from the main parking lot of Herrontown Woods, fortunately has lots of eggs again this year, both woodfrog and the whitish clusters of salamander eggs. 

One of the more comic moments was the spotting of a male woodfrog trying to mate with a salamander. The salamander wanted nothing to do with it. In fact, the salamanders don't directly mate. Rather, the males show up at a vernal pool ahead of time, deposit spermatophores, then wait for the females to come along to pick them up. The system seems farfetched, but the proof is in the eggs that will soon hatch. Hopefully, the vernal pools will keep enough water to sustain the tadpoles and salamander larvae as they grow to adulthood in these little oases in Herrontown Woods. 

Volunteer Cozy Sierra caught the spirit of the Princeton Salamander Crossing Brigade in a t-shirt she had made.