Montana Field Guide

Pacific Treefrog - Pseudacris regilla

Adults have a dark, conspicuous eye line extending from the nostril to the shoulder. Basic coloration varies, with background color green, brown, gray, reddish, or bronze. Dark spots and stripes are often visible on the head, back, and legs. Most have a dark Y or triangular spot on the head between the eyes. Adult body length is .75 to 2 inches. Eggs and Tadpoles: Eggs are laid in small clusters of 10 to 70. The tadpoles are brown/bronze with eyes located on the sides of the head.

This is the only frog in montana with a combination of obvious toe pads and an eye stripe ending at the shoulder.

Montana Range

Pacific chorus frogs are regularly found in the water only during the breeding period in spring. They announce their presence during this time by calling frequently at night and sporadically throughout the day. Following breeding, they move into adjacent uplands and are rarely seen. In western Montana they breed in temporary ponds in lower elevation forests and intermountain valleys shortly after snowmelt. Eggs hatch in 2 to 3 weeks and tadpoles take 8 to 10 weeks to metamorphose (FWP). Use shallow, quiet waters for breeding. Move along ground or in low shrubs at night. Take shelter during day in dense veg., under rocks/logs, in rodent burrows, etc. (Nussbaum et al. 1983).

Severe droughts can affect populations (Schaub and Carsen 1978). Primarily nocturnal (Black and Craig 1970).

N ID: males arrive in breeding ponds early/mid Apr; females mid/late Apr. Eggs layed Apr-mid May; hatch early/mid May. Metamorph. mid Jul-mid Sep. Prefer warmer, more open ponds, but obs. calling in water 2 C, air 0.5 C (Schaub and Carsen 1978).