Field Notes: March of the Amphibians

For many naturalists, one of the most thrilling times of the year is approaching:  the annual migration of the amphibians from their overwintering sites in the forest, down to their breeding grounds in the wetlands and vernal pools below. 

This event, frequently referred to as “the big night,” can occur anywhere from late February to early April in our region and is often, more realistically, a series of nights when a collision of perfect weather circumstances — ground thawed, actively raining, and above 40 degrees —draws cold-blooded vertebrates of all shapes and sizes out of their burrows with only one thing on the mind: get to the water and find a mate. Because of their need for a very particular environment to lure them out of hibernation — really, for amphibians, it’s called brumation — these migratory events can be massive, with salamanders, toads, and frogs of all makes and shapes getting moving and getting busy suddenly — and all at once. 

The Hudson River valley is the most biodiverse region of New York. This distinctive ecological corridor, which stretches from Westchester county all the way to Albany, boasts the largest number of unique types of amphibian in the state–roughly 85% of New York’s 33 amphibian species.

Amphibians, as you might know, are typically shy, living underground, in crevices and under logs, hidden from human eyes for most of the year. But on these “explosive” migration nights, observers have their best — and sometimes only — chance to glimpse some of the rarest species. In Pine Plains, amphibian enthusiasts and migration volunteers have documented yellow-spotted salamanders, wood frogs, blue-spotted/Jefferson complex salamanders, spring peepers, four-toed salamanders and red-backed salamanders all moving en masse on a single evening. Perhaps most remarkable, many — if not all — of these creatures return each year to the same breeding site, likely the very place where they were born, as did their parents before them.

While the migration is an exciting moment in the life cycle of frogs and salamanders, it is also highly dangerous. Humans have severely disrupted these ancient migration corridors, fragmenting the amphibians’ habitats with houses and roadways making their journey all the more treacherous. Crossing active roads in particular can — and does — lead to incredibly high mortality rates each season because the amphibians are often hard to see and avoid with just headlights.

Because of this, every year the NYSDEC and other local ecological organizations train and organize volunteers to support the amphibian movement in an effort called Amphibian Migrations and Road Crossings or AM&RC, encouraging citizens to not only avoid driving on wet spring nights but to actually get out on the roads, stop traffic and usher the critters along to safety. Since the inception of AM&RC in 2009, volunteers in the Hudson Valley have documented, and likely saved, over 66,000 amphibians on migration nights! Climate change and the higher frequency of early, unpredictable, and disjointed spring weather has also led to devastating impacts on amphibian populations. 

One of the shining stars of our local amphibian migration is the Yellow-spotted salamander, a native species of mole salamander that is strikingly strange and large with stout legs, bulbous eyes, and fluorescent yellow spots along its blue-black back. Yellow-spotted salamanders are nocturnal and fossorial, meaning they live almost entirely beneath the ground, only emerging occasionally to forage and, of course, in early spring to breed.

Breeding occurs in vernal pools, small temporary and fishless woodland ponds that fill up in the winter and spring and dry out by summer’s end. Males arrive first on these early warm wet “big nights” and spend a raucous night dancing together in the pools — a type of courtship behavior called liebsspiel — ultimately leaving gooey white sperm packs in the water attached to leaves and twigs in the pond’s shallow depths for the females to choose from. The females then follow their chosen mates to the deposited spermatophore, fertilize themselves, and lay clumps of eggs that look like cloudy gelatinous mounds in the water, which hatch one to two months later. These salamanders are also the only known vertebrate to share their body with algae. Their eggs play host to a species of algae called Oophila amblystomatis, which literally means “lover of salamander eggs” — found nowhere else in the world. Yellow-spotted salamanders are known to live up to 30 years.

So, what can you do to help? 

1. On early spring nights when the temperature rests around 40 degrees and the weather is wet, avoid driving as best you can! I, personally, respond to all early spring evening invites with a “salamander-permitting” RSVP. Here in Pine Plains, we have a number of known road crossings, notably the area around Thompson Pond and Stissing Mountain. Please try to avoid driving through this area! Know another salamander crossing location? Tell us in the comments!
2. Get trained with the AM&RC and join a crew of volunteers! A virtual training through the NYDEC is planned for February 24th.
3. Tell everyone you know about this wild and weird event. Share a salamander factoid or story or photograph — you never know how many lives might be saved. 

Hannah Schiller is a local herbalist, ecologist, and environmental educator. She lives in Pine Plains with her partner and two children and is a member of the Pine Plains Conservation Advisory Council. You can read more of her nature writing on her Substack In the leaves.