Montana Field Guide

Medium-sized, dull grayish brown wren (length 12.5 - 15 cm; mass 15-18 g). Adult has grayish-brown upperparts finely speckled with white and black, with contrasting cinnamon rump; tail brown above with black bars. Underparts dull white finely streaked gray on throat and breast. Sexes alike in all plumages. Distinguished from most other wrens by combination of medium size with relatively long tail, paler coloration finely speckled above with black and white markings, noticeable black subterminal bar on tail, and bobbing habit and cheery, distinctive call. (Lowther, P. E., Krooodsma, D. E., and Farley, G.H., The Birds of North America, No. 486, 2000).

In the Bozeman area, normal migration periods are May 8 to 25 and August 25 to September 7.

The Rock Wren is well name. Most Descriptions of Rock Wren habitat mention "rock" for this pale wren of arid, western North America. Still, these wrens are also found in nonrocky habitats, as long as there exists areas "rich in crevices, interstices, passageways, recesses, and nooks and crannies of diverse shapes and sizes" (Ryser 1985:410 in Lowther, Kroodsma and Farley, 2000).

Insects and other arthropods (Lowther, Kroodsma and Farley, 2000).

Nest in cavity or crevice in or among rocks. Eggs usually ovate in shape. Pure, glossy white with fine spots of reddish brown. Clutch size commonly 5-6, as few as 4, and as many as 10 (Lowther, Kroodsma and Farley, 2000). From Wyoming to Alberta, egg records are from May 27 to July 15, and nestling records from June to July 23.