"Big Night" – Amphibian Crossing!
By Jennifer Meikle, Environmental Educator
I was fifteen years old and just beginning to figure out what I wanted to research for a science class. I had an interest in amphibian research studies but wasn’t really sure where to start. My teacher suggested that I volunteer with a close by nature center, as they were looking for some help with the upcoming “Spring Amphibian Migration.”
At the time, I didn’t yet know very much about amphibians and their so-called migrations, but my teacher urged me to sign up, so I did. The person I had emailed from the nature center told me to show up at eight o’clock at night, and not knowing what to expect I brought my younger sister along. Our parents dropped us off in the parking lot where we met with the woman I had emailed. It was two women, and they chatted idly while finishing up whatever they had to. They locked up, and then my sister and I followed them over to a van. One of them carried a very large spotlight.
For the next hour or two, we circled the backroads surrounding the nature center in that van—very, very slowly—as one of the women hung her body out of the sliding door while holding the large spotlight and shining it down onto the wet, dark road. We all kept our eyes focused on it, for even the smallest movement or hop. Anytime someone saw something, they would shout and the driver would stop the van. We would all hop out and investigate. Many times, it was a frog, hopping into the path of the car, and we took turns picking them up and placing them on the other side of the road in the direction they were heading, safe from the path of the wheels. Other times, it was a salamander, and we did the same. I will never forget my first time seeing a Yellow Spotted Salamander; its large, shiny black body was covered in bright yellow spots. It was the size of my hand. My sister and I were amazed. I had never seen any salamander so big, despite being an outdoor and animal loving kid. To think that something like that was living just under my nose and I had no idea!
What my sister and I had experienced is what most herpetologists call “Big Night.” It is the first or second consecutive rainy night where it’s 45 to 50 degrees out, usually around late March or April. Hundreds (sometimes even thousands depending on the area) of amphibians awaken from their hibernation, and crawl out from the soil of the forest floor. They begin their march to the Vernal Pools, which are temporary woodland pools that are filled by rainwater and snow melt, sometimes traveling up to several hundred yards. Because these pools are seasonal and often dry up by mid to late summer, fish don’t live there, giving eggs and larvae a fighting chance to survive. Amphibians like the Yellow Spotted Salamander, the Jefferson Salamander, the Blue-Spotted Salamander, the Spring Peeper, and the Wood Frog depend on vernal pools to breed and over time their life cycles have evolved around them.
Generations of amphibians have repeated this trek for thousands of years, and every year the vernal pools typically attract the same individuals and their descendants. In many cases, these amphibians are returning to the very same pool where they themselves were born to continue the cycle. When a road runs between the forest where they live and the pool where they breed, they must cross it to make it to their destination. Unfortunately, this results in a concerning number of deaths of many amphibians each year. A study in New York State found that 50-100% of amphibians attempting to cross a paved rural road did not make it, and researchers in Massachusetts determined that the local extinction of the Yellow Spotted Salamander could happen in as little as 25 years, just because of road mortality.
If you are interested in becoming involved and helping amphibians make it safely to the other side of the road, many nature centers accept volunteers for the “Big Night,” and there are also amphibian migration and road crossing training videos online if you want to learn more.* Keep in mind that on a dark and foggy night, visibility is poor, so if you get outside make sure to bring headlamps, flashlights, and wear reflective gear for your safety! And finally, during the warm rainy nights of spring, please drive slowly and carefully—Amphibian Crossing!
*Woodcock Nature Center currently does not have volunteer opportunities for "Big Night."
Gibbs, James P, and W Gregory Shriver. Can Road Mortality Limit Populations of Pool-Breeding Amphibians?
Holland, Mary, and Chiho Kaneko. Naturally Curious: A Photographic Field Guide and Month-by-Month Journey through the Fields, Woods, and Marshes of New England. Trafalgar Square Books, 2019.
“Salamander Crossing Brigades: FAQ.” Harris Center | Making Tracks in the Monadnock Region Since 1970, 24 Feb. 2023, https://harriscenter.org/programs-and-education/citizen-science/salamander-crossing-brigades/faq.