Eastern ribbon snake sightings

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Eastern ribbon snake sightings

Post  Admin on Tue Aug 14, 2012 10:34 pm

If you saw a yellow-striped snake, could you tell whether it was a garter snake or a ribbon snake? To the untrained eye, the eastern ribbon snake looks like a thin gartersnake, the most common snake in the Northeast. The ribbon snake is quite uncommon in both Vermont and New Hampshire, where the species reaches the northern limits of its breeding range, but populations nevertheless appear to be declining.

Historically, ribbon snakes were found in 10 Vermont towns, but recent sightings compiled by the Vermont Reptile and Amphibian Atlas Project have been limited to six towns: five in western Rutland County and one in the lower Connecticut River Valley. Although slightly more widespread in southeastern New Hampshire, ribbon snakes have apparently vanished from five towns where they once occurred in that state. What is going on with this gentle, semi-aquatic snake? Is it truly in decline? Or could its similarity to the ubiquitous garter snake be skewing reports?

At first glance, ribbon and garter snakes look identical. They’re both dark-bodied snakes with three, yellowish stripes that run from head to tail (one on each side and one down the middle of the back). However, there are several key field marks that can help distinguish between these closely-related species. The ribbon snake’s best field marks occur on its head -- look for an unmarked, white upper lip, a vertical white spot in front of the eye, and a reddish or mahogany-colored head. Garter snakes have dark grey or olive-green heads and a yellowish lip with dark edges outlining each labial (lip) scale. They also lack the white spot in front of the eye (although they may have a smaller, less conspicuous yellowish mark in front of the eye).

In general, ribbon snakes are slender, cleanly-marked snakes, with uniformly dark bodies that contrast with distinct yellow stripes and a mahogany-colored stripe on their lower sides. They rarely have a pattern between the yellow stripes. Garter snakes, which can be highly variable, often have a checkerboard type pattern between the side stripes, and may or may not have a mahogany stripe.

Many field guides report that a ribbon snake has a longer, more slender tail than a garter snake. However, to the casual observer, distinguishing the relative length of a snake’s tail can be rather troublesome. First you have to know that a snake’s body ends and its tail begins at the cloaca, and you need a sense of what a long tail versus a short tail is. To clarify, a ribbon snake’s tail is a third or more of its body length, compared to -- or less for a garter snake. Since the cloaca is generally only visible from below, in most cases you’ll need to capture the snake to determine the relative length of its tail. (Both ribbon and garter snakes are easily handled, as they are non-venomous, and relatively small and gentle, although they often emit a musky odor when touched).

The primary characteristic of ribbon snake habitat is water, from which they rarely stray far. Ribbon snakes are usually found along the shorelines of a variety of wetland types, from ponds and lakes to streams, bogs, marshes, and swamps. They especially like shorelines with dense herbaceous vegetation where their ambush style of hunting can be most effective.

This habitat preference is reflected in their choice of prey; most studies show the majority of their diet is made up of amphibians and fish. In one study from Nova Scotia, ribbon snakes were found to only prey on frogs and minnows, all of which were captured in the water but consumed on land. On several occasions, researchers watched ribbon snakes dive underwater and remain submerged for more than three minutes. They also saw them resting among shoreline grasses with their heads elevated and swaying back and for that about the same frequency as the windblown grass, an act that suggested behavioral mimicry to enhance their camouflage.

In order to develop sound conservation strategies for any species, we first need to know where the animals are found. For the ribbon snake, you can help by carefully scrutinizing any sightings of garter-type snakes observed in the warmer, low-lying regions of the twin states (Champlain Valley, southern Connecticut River Valley, and southeast New Hampshire), especially those sightings that are adjacent to wetland habitats. If you think you’ve seen a ribbon snake, report your sighting to either the Vermont Reptile and Amphibian Atlas Project ([You must be registered and logged in to see this link.] or the New Hampshire Nongame and Endangered Wildlife Program ([You must be registered and logged in to see this link.]

Steven D. Faccio is a conservation biologist at the Vermont Center for Ecostudies; he lives in Strafford. The illustration for this column was drawn by Adelaide Tyrol. The Outside Story is assigned and edited by Northern Woodlands magazine and sponsored by the Wellborn Ecology Fund of New Hampshire Charitable Foundation: [You must be registered and logged in to see this link.].

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