Amphibian Migrations and Road Crossings
Thank you volunteers! Migration season has passed and we appreciate everyone's participation this year. If you're new to the project, check out the "Why Did the Amphibian Cross the Road?" project video (leaves DEC website).
Why did the salamander cross the road?
Many amphibian species, like this spotted salamander,
need healthy forests and wetland complexes. (L. Heady)
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 March and early April, 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 need to cross 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.
More than 1,000 volunteers have helped
more than 40,000 amphibians cross roads safely
during migrations in the Hudson Valley.
(L.Heady)
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.
Resources for Volunteers
AM&RC volunteers are able to self-train by using the following online materials:
- Migration Alert Emails: Volunteers are encouraged to sign up to receive migration alerts and project updates by subscribing in the blue "DEC Delivers" box above. Most email correspondence from this list is limited to February through April.
- Volunteer Handbook (PDF): The handbook provides lots of details on volunteering, including how to prepare and stay safe, what to expect, and what to bring on a migration night.
- Virtual Volunteer Training: (February 28, 2023 webinar recording) | Webinar transcript (PDF): This 90-minute recording of our most recent virtual training covers the basics and also includes a demo of Survey123, review of confusing species, and a Q&A session.
- Volunteer Training Modules (leaves DEC website): This five-part recorded PowerPoint series has audio narration and is recommended for volunteers who have not attended an in-person or virtual training (or for those who need a refresher).
- Online Data Form: Check back next season.
- Online Data Form Instructions (PDF).
- Data Form (PDF): Use for printing and recording observations in the field.
- Vehicle Sign for Volunteers (PDF): Use to display in your vehicle during migration nights, to identify your participation in AM&RC.
Additional resources to learn amphibian identification include:
- Amphibian Identification Guide (PDF) with photos of species most often encountered during migrations in the estuary watershed.
- Woodland Pool Wildlife (PDF)
- Woodland & Vernal Pool Salamanders of NY State (PDF)
- Frogs & Toads of NY State (PDF)
Additional resources to learn about vernal pools and mitigating road crossing mortality (recording links leave DEC website):
- Webinar - Introduction to Vernal Pools with Dr. Mary Beth Kolozsvary (January 25, 2022 recording) | webinar transcript (PDF)
- Webinar - Amphibian Migrations: Case Studies in Reducing Mortality at Road Crossings with Brett Amy Thelen and Chris Slesar (February 1, 2022 recording) | webinar transcript (PDF)
- Webinar - Vernal Pool Habitat Conservation with Dr. Aram Calhoun and Dr. Matt Schlesinger (February 15, 2022 recording) | webinar transcript (PDF)
Learn more about the project:
- "Why Did the Amphibian Cross the Road?" Project Video (leaves DEC website)
- AM&RC Project Fact Sheet (PDF)
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.
