Big night: Amphibian populations crossing the roads

One of eight four-toed salamanders observed crossing a road in the Town of Catskill on February 25. (photo by Kelly Mckean)

They move in the dark of night, by the hundreds if the weather is right — 40 degrees with a steady rain. They are small and slimy, yet cute, although some salamanders may be up to eight inches long. Many of them venture onto roads and get crushed flat by the tires of passing cars.

Last year, Ben Houston of Woodstock started tracking the late winter migration of salamanders, frogs, and toads. He wants to save some of the slow-moving creatures from death by automobile, but the main reason he’s out on the road at night is “because they’re so beautiful, and you don’t get to see them very often.”

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The amphibians’ goal, as soon as the warming weather wakes them from hibernation in the forest, is to lay their eggs in a vernal pool. Often they have to cross a road to find one of these tiny woodland ponds that will dry up in the summer. “They prefer spring pools because the pools are fleeting, with no predators — prey fish or other things that would eat the eggs,” explained Houston. “Last year, we went out in our neighborhood at night and saw hundreds of frogs and salamanders. Probably 80 to 90 percent of the ones we saw were dead because of roadkill.”

When conditions are ideal, amphibian trackers call the occasion a Big Night, when hordes of creatures can be seen on the roads. This year there were a few intrepid amphibians observed on February 25, two weeks before the earliest start date since 2009, when the Hudson River Estuary Program of the New York State Department of Environmental Conservation (DEC) began recording migration data. A thunderstorm and a sudden temperature drop seem to have curtailed the initial exodus. “We might see a series of little nights this year instead of a Big Night,” said Houston.

Last year, Georgia Asher, a Woodstock Land Conservancy board member, saw a fair-sized cohort of wood frogs, one of the first species to head out, on March 10. A second migration occurred in late March or early April. “Some years it doesn’t happen until well into April,” said Asher, who has been tracking amphibians for several years and reporting her observations to the DEC. “They migrate in the dark, and they need rain coming down because their skin has to remain wet so they can breathe. It has to be close to 40 degrees, since they have trouble moving if it’s too cold.”

Because amphibians are cold-blooded, they freeze solid in the winter. “They stop breathing,” said Asher, “and their heart stops. When the weather warms up, they come back to life.”

 

Crossing guard programs

Among the goals of the Hudson River Estuary Program is conservation of forests, woodland pools, and associated wildlife. The organization depends on citizen scientists to scout out the migrations of woodland pool amphibians in an effort to map road crossings and habitats. “This information can then be used for community planning and for groups of volunteers interested in starting ‘crossing guard’ programs for the breeding season,” notes the DEC website. “Eventually, we can also learn whether the timing of spring migrations is shifting due to climate change.”

Houston, who works as an environmental engineer, explained the rationale behind protecting frogs and salamanders. “We’re starting to learn about what happens when an element of an ecosystem is impacted. They might be an important food source for other members of the community, birds or mammals, which suffer when they aren’t there. Amphibians also consume a lot of insects, including mosquito populations, so a decline in amphibians can cause an increase in insects contributing to vector-borne diseases.”

Human settlement causes fragmentation of forest habitats and loss of wetlands, a trend that has contributed to a decline in amphibian populations in the Hudson Valley. Since the migrants may have to travel up to a quarter-mile to reach a woodland pool, they often have to cross roads or driveways.

On last year’s Big Night, said Houston, he and his wife were astounded by “the size of salamanders we’d never seen before and the sheer number of them marching across the road. I think we assisted around 50. They would come up on the shoulder and start marching across the pavement, slowly because it’s chilly. They’d take one or two steps or hops, rest a moment, and then we chased them across or scooped them up and carried them to other side.”

So pay attention to the weather and go to the DEC website (see highlighted box) if you want to get a good look at spotted, Jefferson, or marbled salamanders, eastern newts, wood frogs, spring peepers, or American toads. You won’t get this chance too often.

 


Crossing guard guidelines

To get on the DEC’s email list for migration updates, send a request to woodlandpool@dec.ny.gov. See http://www.dec.ny.gov/lands/51925.html for information on amphibian migration, data sheets for reporting to the DEC, an identification guide, and safety precautions for both humans and amphibians, such as:

Bring a flashlight or head lamp.

Wear a reflective vest and rain gear.

Stick to quiet back roads.

Do not interfere with traffic.

Do not pick up animals by the tail.

Make sure your hands are clean and free of soap, lotion, perfume, insect repellent, or any other chemicals that can be absorbed through the animals’ skin.

If you handle a toad, rinse your hands afterward, since toads can emit poisons that might harm animals you pick up later.

If you use a bucket or container to help move the animals to safety, make sure it’s clean and free of any chemical residues.

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