Description
The Western Chorus Frog is a small, smooth skinned treefrog.
Colour varies from green-gray to brown. There is a dark stripe through
the eye and a white stripe along the upper lip. It is distinguished from
most other treefrogs by the three dark stripes down the back. In some individuals
the stripes are broken. Maximum adult size about 4 cm.
Call
The breeding call is very similar to the Boreal
Chorus Frog but is shorter and faster in pulse rate. It resembles the
sound of drawing your finger down the teeth of a comb.
Confusing Species The Western Chorus Frog
is almost identical to the Boreal Chorus Frog. It has longer hind legs
but is best distinguished by its call or location. In Canada their distributions
do not overlap.
Distribution
In Canada, the Western Chorus Frog is found only in southern
Ontario and along the Ottawa and upper St. Lawrence river valleys in Quebec.
It is also found through much of the eastern United States and overlaps
with the Boreal Chorus Frog in the central United States. It was introduced
to Corner Brook Newfoundland in the 1960's but apparently is now extirpated
from there.
Habitat
The Western Chorus Frog's preferred habitat is forest openings around woodland
ponds. They will breed in almost any fishless pond with at least 10 cm
of water, including roadside ditches, gravel pits, flooded fields, beaver
ponds, marshes, swamps or shallow lakes.
Reproduction
Western Chorus Frogs breed very early in the spring and may
begin as early as March although most calling is in April. They may chorus
during the day as well as at night. A series of small egg masses are laid
and attached to vegetation. Eggs hatch within a few weeks and tadpoles
finish transforming by early summer. They are usually mature in one year
and rarely live beyond three.
Natural history
Chorus Frogs hibernate beneath logs or underground and are freeze-tolerant.
They are among the first frogs to emerge in the spring. They feed on small
insects and other invertebrates and are eaten by a wide variety of predators.
Conservation Concerns
There is no evidence for decline in Ontario populations of the
Western Chorus Frog, however, it has declined throughout the St. Lawrence
Valley in Quebec as a result of habitat loss. A population introduced to
Newfoundland is apparently now extirpated.
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