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Western Chorus Frog
Pseudacris triseriata
by Jeff
LeClere
Status
No status assigned in Minnesota.
Description
These tiny frogs are probably Minnesota's
smallest frogs with a body length of slightly over an inch.
The ground color may be varying shades of brown, gray, olive
or reddish. There are three relatively wide, longitudinal
stripes down the back. These may be broken. The stripes are
brown, rusty or greenish. The belly is plain light brown.
There is a stripe from the snout through the nostril and eye
and continues down the side to the groin. The body is long
and slender compared to the short legs. The toe pads are very
tiny.
Subspecies
There are reported to be two subspecies
in Minnesota: the western chorus frog, P.t. triseriata, and
the boreal chorus frog, P.t. maculata. Some consider the boreal
chorus frog a separate species. These two are reported to
intergrade (or hybridize) in central and southwestern Minnesota.
The boreal chorus frog is separated from the western chorus
frog by a shorter tibia length, stripes broken into spots
and an overall greenish coloration. These characters are not
always geographically consistent.
Range
The chorus frog is found statewide. The
boreal chorus frog supposedly occurs in northwestern Minnesota
and the western chorus frog found in the southeast. There
is a large band of intergradation in all of central and southwestern
Minnesota.
Habitat
The western chorus frog is found in a
variety of habitats, but never far from woodlands. They breed
in temporary pools of water to large wetlands and even in
shallow parts of lakes. Unlike other species of amphibians,
this frog can survive in urban areas.
Habits
Chorus frogs begin seasonal activity in
late March or early April, and immediately begin calling and
breeding. The call sounds like a "pprrreeep" similar to a
chirping cricket or running a thumbnail down the teeth of
a fine toothed comb. Most breeding activity is done by the
end of May, but individuals may be heard giving their advertisement
call in June or July, especially in evening or after rains.
Chorus frogs lay small clusters of eggs. The tadpoles metamorphose
in about 2-2 1/2 months. Western chorus frogs do not move
far from their wetlands during the summer, especially in urban
environments. They apparently overwinter under rocks or logs.
Food
Western chorus frogs feed on small invertebrates.
They may hunt in low shrubs but due to their short limbs,
they do not climb very high and they are not quite as acrobatic
as other treefrogs.
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