Amphibian Migrations And Road Crossings

Why did the salamander cross the road?

Have you ever witnessed large numbers of salamanders and frogs crossing the road on rainy spring nights? Ever wonder where they came from and where they're going?

Mole Salamanders and Wood Frogs

The forests of New York are inhabited by a group of amphibians that breed in small, temporary wetlands called woodland pools. In the Hudson River estuary watershed, this group includes:

• spotted salamander
• Jefferson-blue spotted salamander complex
• marbled salamander
• wood frog.

​​The salamanders are seldom seen, as they spend much of their time under leaves and moss on the forest floor, in burrows created by small animals and hunkered down under rocks and rotting logs. They belong to the family Ambystomatidae and as a group, they are referred to as "mole salamanders" because of their underground habits. They forage primarily at night on a variety of invertebrates, including earthworms, snails and insects. Wood frogs also live on the forest floor and feed on invertebrates. Mole salamanders and wood frogs (PDF) are important links in forest food webs and indicators of healthy, functioning ecosystems.

Seasonal Migrations and Road Mortality

Spotted salamander, Jefferson-blue spotted salamander complex, and wood frogs emerge from winter hibernation on rainy nights in late winter and early spring, after the ground has thawed and evening air temperatures stay above 40ºF.

When weather conditions are right, they make their way from the forest to woodland pools, where they'll mate and lay eggs. There can be many hundreds of amphibians on the move; amongst nature enthusiasts, these annual migration events are often referred to as "Big Nights." (The marbled salamander is different from the other mole salamanders, as it breeds in the fall.)

But why are these amphibians so frequently seen crossing the road? Migration distances to woodland pools can vary from a few hundred feet to more than a quarter of a mile. Unfortunately, because forest and wetland habitats are often disconnected by development, many migrating amphibians encounter roads and long driveways, leading to mortality of slow-moving wildlife, even in low traffic areas.

How can you help?

The Amphibian Migrations and Road Crossings (AM&RC) Project enlists volunteers to find locations where migrations cross roads; document weather and traffic conditions; record migrating amphibians; and help them across the road. Since the project started in 2009, more than 1,000 volunteers have counted at least 66,000 amphibians and observed 20 species. They assisted more than 40,000 amphibians across roads during migrations and counted nearly 19,000 migrating amphibians killed by passing vehicles.

Volunteer observations are building our understanding of where mole salamanders and wood frogs are especially vulnerable during their annual migrations and where their habitats are located. This information can be used for community planning and for groups of volunteers interested in starting "crossing guard" programs for the amphibian breeding season.

Volunteer Materials

The Amphibian Migrations and Road Crossings project is part of a larger Hudson River Estuary Program initiative to partner with local communities to conserve natural areas and habitats that sustain the health and resiliency of the entire estuary watershed.