As the official first day of spring (March 20th!) is rapidly approaching, so are warm and rainy nights. For thousands of amphibians – vertebrate animals with wet, mucus-covered skin, such as frogs and salamanders – this also means the beginning of a critical event in their life cycle.
Under perfect spring conditions (rainy with temperatures 45°F or higher), you may see dozens, even hundreds of migrating amphibians crossing the road at night. Prompted by these environmental cues, “Big Night” is the mass migration of amphibians moving from winter habitats to breeding sites, such as wetlands and vernal pools. Vernal pools are temporary bodies of water that dry up by summertime, but during the springtime provide a refuge from aquatic predators, such as fish, increasing the survival chances of amphibians’ young. While the term “Big Night” implies a singular event, migration occurs throughout early to mid-April across Maine. You can still find smaller numbers of migrating amphibians outside of these “Big Night” conditions.
Unfortunately, successful migration can be challenging, as many migratory routes intersect with our roads. Maine Big Night is a community science project that aims to reduce amphibian road mortality by assisting them safely across roads, all while collecting vital data. Not only do volunteers save thousands of amphibians each year, this data also helps inform wildlife conservation, better understand our road infrastructure’s impact on wildlife connectivity, and improve road planning.
Road improvements that provide wildlife passage also make roads much more resilient to damage from major weather events. These roads can then reduce wildlife-vehicle collisions and the potential for road washouts, making it safer for animals, drivers, and water quality. If you notice a large number of amphibians on a road near you and want to get involved in this project, visit mainebignight.org to learn more.
Spotted salamander