Hudson Valley forest-dwelling amphibians come out from under winter cover each spring to breed and lay their eggs in vernal pools. The annual nighttime migration from woods to water usually takes place in late March or April, when the soil has thawed, air temperatures have risen above 40 degrees Fahrenheit and a rainy night creates the conditions the creatures require for movement.
Sometimes the migration occurs in a single evening, on what’s known as a “Big Night.” This happened on March 22 in 2010 and March 26 in 2009. But increasingly, the salamanders and frogs have been making their journey to breed over the course of a series of nights; it’s all very weather-dependent.
Last year, a brief spell of unusually warm temperatures in February triggered the earliest date of amphibian migration recorded in this region since the state Department of Conservation (DEC) began keeping track of it in 2009. Small numbers of amphibians on the move were counted as early as February 25 in 2017.
This year we’ve also had warm temperatures in late February that generated early migration, says Laura Heady, the DEC conservationist who launched the Amphibian Migrations and Road Crossings Project and continues to oversee it. “While I haven’t received any volunteer data forms yet, I did receive anecdotal accounts of wood frogs on the move in Ulster and Dutchess Counties, and some were even heard singing. Spring peepers have also been heard.”
These unusually early movements were triggered by the rainy nights that followed those unseasonably warm days near the end of February and early March, before the nor’easters hit the region, she adds, but “to my knowledge, no salamanders have been observed yet. Now, with snow cover and low temperatures, it looks like we’re in a holding pattern until conditions are right for the next wave of movements to vernal pools.”
Land-use changes and habitat loss and degradation have had an impact on the amphibian population worldwide, says Heady, with several of the amphibian species found in the Hudson Valley of conservation concern, including the spotted salamander, the Jefferson blue-spotted salamander and the wood frog.
Climate change also appears to be a factor in conservation challenges. “The weather at this time of year seems to be increasingly erratic, making it difficult to predict when migrations may occur, and also resulting in a series of migration nights spread over the season rather than one or two ‘Big Nights.’ Time will tell for 2018.”
Vernal pools are temporary wetlands formed from snowmelt and rain. The impermanent nature of the ponding (the pools dry up by summer) helps to ensure that amphibian eggs will be as safe as possible once laid there, with no resident predator population sharing the waters. (Spring peepers can also use other aquatic habitats like marshes and ponds for breeding, where upon arrival, the males start “peeping” to attract females.)
But getting to these environments safely is a challenge for the small creatures. They travel great distances (as much as a quarter-mile, which is considerable for a tiny salamander or frog) and face a virtual minefield of impediments along the way – easy prey for predators, and often killed by vehicular traffic at road crossings before they can make it to their destination. The mortality rate from traffic is high.
The purpose of the Amphibian Migrations and Road Crossings Project, a collaborative effort between the DEC Hudson River Estuary Program and Cornell University, is to obtain data that help the population survive. Volunteers identify new crossings, document the migration and act as crossing guards, sometimes literally picking up amphibians to move them across the road out of harm’s way. And since no conservation organization could possibly have a large-enough staff to carry out a project of this nature, says Heady, the hundreds of volunteers make a big difference in accumulating data and ensuring the survival of thousands of local amphibians.
“I am very excited to see the growing interest in the project. This year, the e-mail listserv has grown to more than 820 subscribers. One of our volunteers, Meg Sodano, is a natural science illustrator who has illustrated a beautiful new children’s book about the migrations, called Salamander Sky. Meg was kind enough to design and donate an illustration for our project this year, featuring the species we see most commonly during Hudson Valley migrations: spotted salamander, wood frog and spring peeper.”
An informative short video about the amphibian volunteer program, created in partnership with the Marist College Media Center, is available to view on the DEC YouTube channel at http://bit.ly/2GNTjwc. Visit http://on.ny.gov/1iDfCFh for more information and to download the data collection form that participants in the program need. Volunteers are advised to carry a bright light, wear a headlamp and reflective vest and stay alert to traffic. “Safety is the number-one priority,” says Heady.
For more information about the Amphibian Migrations and Road Crossings Project, email DEC conservation and land-use program coordinator Laura Heady at firstname.lastname@example.org or visit http://on.ny.gov/1iDfCFh.