Current Nature: A Spring Chorus Of Frogs

It may still feel like winter, but spring is fast approaching. Soon, frogs that have been dormant for the past few months will wake up. On Nantucket, we have fewer amphibian species than on the mainland, but the ones we have here are sure to excite. Although small and hard to see, the most vocal frog on island is the Spring Peeper. The exact date that peepers start calling each year is dependent on the weather. They typically start in early-March and are most vocal from mid-March through mid-April; however, in particularly warm years, they may be heard as early as January. Despite having a body length of only around one inch and a mass of around 0.15 ounces, the calls of these frogs can be heard over a large geographic area. Only the males make calls as part of a mating ritual to attract a female partner. Calls are high-pitched and loud, clocking in at around 90 decibels. Each male may repeat the same call up to 13,500 times per night! Individually, calls resemble a ‘peep’ sound but when heard in a large chorus, they more closely resemble the sound of sleigh bells. Spring Peepers tend to be most active on warm, wet, and overcast nights; sometimes in these conditions you can hear them from over a mile away.

Nantucketers often revel in hearing the first peeper calls as they are one of the earliest harbingers that spring is truly approaching. Spring Peepers wait until ponds and wetlands have fully thawed before beginning their choruses. Tracking the phenology of Spring Peepers’ emergence each year can be an excellent way to understand any potential impacts that climate change may have on this species. We can look to see if earlier emergence dates are correlated with a rise in winter and early spring temperatures and if so, assess the risk that may be having to local populations. Researchers studying Spring Peeper phenology try not to only document the first call date, but also when the peak of acoustic activity is. As you can imagine, it is hard to accurately calculate exactly how many peepers are calling. Rather, researchers use a combination of acoustic monitoring and song meter technologies to estimate how many frogs are present. During their peak activity, there may be so many individuals present that even the scientists studying them cannot determine an exact number and simply record the peepers as an ‘immeasurable chorus.’

Although most known for their calls, the other aspects of Spring Peeper life history are also fascinating. They have large toe pads and are adept at climbing, but they predominantly spend their time on the ground, hiding in leaf litter or wetland vegetation. Their skin color is affected by temperature and light, allowing them to change quickly for better camouflage against predators. One noticeable mark, is the brown cross on their back. Their diet consists of ants, beetles, flies, and spiders, so if you see one in your garden, you can thank it for reducing the pests around your house. They are widespread throughout their range and not at risk of population decline; however, the loss of wetland habitat and accelerated climate change could have the potential of being detrimental for them in the future.

I look forward to the return of peepers this spring and hope you do too! Let us know when you first hear them.

Stay tuned for more editions of Current Nature, a bi-weekly column featuring seasonal topics, natural history information, and advice on the outdoors from the staff at the Linda Loring Nature Foundation.