Learning Landscape for April: Spring’s Big Night & Vernal Pool Habitat
Learning Landscape for April: Spring’s Big Night & Vernal Pool Habitat
The April Landscape
April is a month of massive transition here in New England. March’s maple sugaring season often runs
into the month’s earliest days, while the tail end of April is filled with new life and much green. Spring emerges
on its own time, and its arrival varies from year to year. Regardless, the pattern of melting, emergence, and
growth remains the same annually, and the events outlined in this Learning Landscape follow the same
trajectory at some point between mid-March and mid-April every year.
This month, we focus on the annual Big Night of springtime – the moment at which frogs and salamanders (and occasionally other damp-dwelling creatures) emerge from their winter hibernation to mate and lay eggs. Frogs and salamanders both burrow deep down in the muddy ground for the winter, lowering their body temperatures to make it through the cold. Then, when the timing is just right, they’ll come out.
The night when amphibians return to the spring landscape is often referred to as the Big Night, and it happens on the first rainy night when temperatures surpass 40 degrees. Generally, this happens once most snow has melted, but sometimes the Big Night takes place when there are still lots of patches of snow around. Frogs and salamanders can be found in ponds and in vernal pools, special (and essential) habitats for these creatures. Explore your surroundings to locate amphibian habitats, and use these spaces as a catalyst for learning about early spring’s burst of life.
Artifacts for Learning
Vernal pools are a special type of habitat found seasonally, generally just in spring and early summer but some large pools hold water through fall. Vernal pools – especially large ones – can seem much the same as ponds.
The major difference is that a vernal pool never contains fish! Vernal pools are found in forested areas, as species found in them rely on the shade of trees for cool water in summer, and use the leaves that fall as a place to hide.
- LOOK in the woods! Vernal pools will be located in place where water accumulates, so look for indentations in the landscape while the snow is still melting. Take note of places where snow melt reveals patches of open water, and re-visit the largest ones to check for signs of life later on.
- IDENTIFY a vernal pool by noting the absence of fish and the presence of either frogs and salamanders or gelatinous egg masses.
Laid by frogs and salamanders, eggs masses look like oversized chia seeds soaked in water. Egg masses can often be found in groups. The masses are made up of clear eggs with tiny, black centers. Eggs with white centers are not fertilized and will not hatch. Egg masses cannot be seen until after the Big Night, but it’s possible to see amphibians engaged in mating and laying egg clusters on the very same night that they’ve
- LOOK in the shallow parts of vernal pools and some small ponds. Egg masses will often be attached to branches or brambles in the water. Polarized sunglasses help greatly with locating masses in early spring when the lack of leaves can create a strong glare on the water’s surface.
- IDENTIFY egg masses by looking for some basic characteristics. Salamander egg clusters have a transparent coating holding them together, and do not always have a rounded shape. Frog egg clusters lack the coating, and are rounder than salamander egg clusters. Salamander egg clusters tend to be more opaque than those of frogs.
The most common salamanders found in New England’s vernal pools are the spotted salamander, Jefferson salamander, and blue-spotted salamanders. It is best not to hold salamanders, but if you must, be sure to have thoroughly washed your hands before touching them, and keep your hands wet while handling.
- LOOK at the edges of vernal pools. Salamanders can sometimes be seen in the same areas where eggs are laid, but are also often found in clear, leaf-filled shallows. On the Big Night, salamanders can be found making their way to vernal pools, so tread with caution as you approach any likely habitat.
- IDENTIFY based on markings and body size. Spotted salamanders have bright yellow spots, blue-spotted salamanders have large blue spots, and Jefferson salamanders have small blue speckles and purple-y skin.
Known for their signature sound, spring peepers are the first frogs to make their presence known, and wood frogs are never far behind! Bullfrogs will coexist with other frog and salamander species, but are predatory and therefore aren’t specific to vernal pools for the same reason that fish aren’t. Their young overwinter as large tadpoles, and feast on frog and salamander eggs in spring. Green frogs can be found in both vernal
pools and ponds.
- LOOK in the leaf litter in the shallows of vernal pools and fish-less ponds. They often hide underneath leaves and peer out, making only the tips of their faces visible. When the ground is wet, look for frogs out of the water.
- IDENTIFY based on size and color. Spring peepers are light brown, with x-like markings across their backs. Wood frogs have brown stripes from their eyes to their back legs, as well as a dark brown patch around and underneath their eyes. Bull frogs are large and green, and their tadpoles are massive. Green frogs are green with small brown circles behind their eyes.
The collection of resources listed below can be used to spark, support, or continue studies related to learning common late winter food sources and the wildlife that they support.
Hilltown Families on Mass Appeal: Vernal Pools
Spring phenology means studying vernal pools! This segment presents much of the information included in this guide in audio/visual format, making it an ideal resource for auditory learners and young folks who cannot read complex text yet!
Learning Ahead: Cultural Itinerary for Western Massachusetts (March & April)
Connect springtime phenology and vernal pool studies with the many other natural and cultural phenomena of the season, including maple sugaring, sheep shearing, locally written literature, poetry month, and more.
Mapping Vernal Pool Habitats Hosts Loads of Learning
The Massachusetts Natural Heritage and Endangered Species Program offers its GIS data vernal pool maps to the public, an incredible resource that can be used to locate nearby vernal pools. Additionally, the resource can serve as an opportunity for citizen science for those who have GIS skills – vernal pools not currently mapped can be added by users!
Lifecycle Studies: Hatching Frog Eggs
After exploring vernal pools and learning about amphibians’ triumphant emergence from the cold winter ground, bring some frog eggs indoors to learn about their growth and development. Be sure to learn to identify egg masses before collecting so as to avoid gathering eggs of a struggling species, and never collect eggs from conserved land.
The Ripple: The Magic of Spring Peepers, the Science of Vernal Pools
How do spring peepers know to start singing? Read to learn about the adaptations that peepers utilize for winter survival and spring emergence, and discover the magic that is nature – spring peepers are guided by something much bigger than themselves, and bigger than us.
Vernal Pools: When Will the Spotted Salamander Eggs Hatch?
If you’ve succeeded in finding a vernal pool that hosts a spotted salamander population, it’s worth knowing the time frame within which to expect eggs to hatch so that you can continue to learn.
Amherst’s Henry Street Salamander Tunnels
Designed to help salamanders cross a busy street on the Big Night, the tunnels are one of few of such projects in the world. With support from the Hitchcock Center, families can visit the tunnels to learn about their design and can self-train to offer support to salamanders on the annual Big Night.
Robin Morgan Huntley, Community-Based Education Correspondent
A native to Maine, Robin joined Hilltown Families in early 2011 as an intern and remained over the years volunteering as a community-based education correspondent until moving back to Maine in 2016. Robin is a graduate of Antioch University with a masters in education. Her interests within the field of education include policy and all types of nontraditional education. For her undergraduate project at Hampshire College, Robin researched the importance of connecting public schools with their surrounding communities, especially in rural areas. Robin currently lives with her husband, cats, dog, and bunnies in Maine. She is a 3rd grade teacher and the founder of our first affiliate community-based education network, Dirgio Learning.