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| An adult Pacific Treefrog showing toe pads and a dark eye line ending at the shoulder |
This frog portrait shows you all the clues needed to identify this native amphibian.
The Northern Pacific Treefrog (Pseudacris regilla regilla) is one of the Pacific Chorus Frogs, and it's Montana's only frog with a dark eye line and obvious toe pads. (Here the wet eye line is reflecting a blue sky.) The light-colored throat also tells us that this is a female, as males have a dark throat patch. The upper body can vary in color from brown to green, bronze to gray, and individual frogs can lighten or darken their color to better match their surroundings. This evening, I discovered this handsome greenish-gray specimen hiding in our grayish wood pile.
I'm betting that you've never seen a Pacific Treefrog - not because I'm a gambling man but because I've only seen three of them in all my years wandering the Montana woods. The adults are nocturnal, hiding in silence during the day, and they only come down to water in spring.
I'm also betting that you've heard them quite clearly, if you've ever spent a spring evening near a small pond or shallow lake in the Pacific northwest. Males arrive at the breeding ponds in late March - from one-quarter to several miles away - calling loudly to the females that arrive a week or two later. The females select a mate in the dark based on his calling behavior. The male repertoire includes calls to attract females, to attract other males, and to space males around a pond.
Pacific Treefrog distribution is patchy in northwestern Montana. Surveys by the Natural Heritage Program have found them widely distributed at lower elevations. In Glacier Park, they've only been reported in the area around West Glacier, and in nearby ponds along the Middle Fork.
Here at the end of the road, a chorus of hundreds on a windless spring night is a milepost that tells us that we've made it through another Montana winter, and the treefrogs' sudden exuberance always stops me in my tracks. The eggs that are laid in April will hatch in mid-May, and the tadpoles will transform into frogs from July to September, depending on the water temperature.
The new adult frogs will leave the water in fall and patiently wait for the return of spring - like a lot of us in these parts.
