140 THE CONDOR Vol. XVI Piranga ludoviCiana. Western Tanager. Common summer resident in the mountains. Nests in fir forests. Migration dates: August 28, 1911, on the Sun River, and June 4, 1912, on Birch Creek. Petrochelidon lunifrons lunifrons. Cliff Swallow. Abundant summer resident of the prairies. Nests commonly both on buildings and on the steep sides of buttes. People in Choteau destroy their nests as fast as they are built, believing that the birds carry bed-bugs. My observations seem to show that the bird.s will not nest on wooden buildings that are kept painted, prefering either stone buildings or unpainted wooden ones. Migration date: June 7, 1912. Hirundo erythrogastra.. Barn Swallow. Summer resident on the prai- ries. Occurs regularly in small numbers but is not common. Migration date: June 7, 1912. Tachycineta thalassina lepida. Northern Violet-green Swallow. Summer resident in the mountain canyons. Most common in the southern part of the region and rare northward. These birds are known as "'Rock Swallows" in this region. Riparia riparia. Bank Swallow. Common summer resident in the prai- rie region. Colonies are very common along the steep clay banks of the rivers. Migration date: May 26, 1912. 8telgidopteryx serripennis. Rough-winged Swallow. Common summer resident. Nests in clay banks along the rivers, .usually as single, scattered pairs, but I have seen several pairs nesting in a colony with the above species. Migration date:May 22, 1912. This swallow was fairly abundant for several days before the other species arrived. Bombycilla garrula. Bohemian Waxwing. Common winter visitor both on the prairies and in the mountains, being most abundant along the foothills of the mountains. Occurs in the mountains rarely in' summer and probably breeds (see CONDOR, XIV, 1912, p. 224). Migration date: March 30, 1912. Bombycilla cedrorum. Cedar Waxwing. Common summer resident on the prairies and in the lower mountain canyons, below 5000 feet. Migration date: June 23, 1912. Nesting generally begins the middle of July, but I found one nest at Choteau that was ttalf built on June 28, and in which the four eggs were laid July. 5 to 8. Lanius borealis. Northern Shrike. Winter visitant. I found it rare in the winter of 1911-12, and saw none at all in 1912-13. From a few observa- tions in other parts of the state I am inclined to think that these birds were rare all over the statO in these two years. Migration date: October 16, 1911. Lanius ludovieianus excubitorides. White-rumped Shrike. Summer resi- dent of the prairie region. Quite common in the summer of 1911, but seen only once in 1912. This occurrence was at Choteau on April 9, when the bird had evidently just arrived. My migration dates for this species in Montana are quite variable, and lead me to believe that this is due to a wide difference in the migration dates of the two subspecies occurring in the state. L. 1. excubitorides evidently breeds only in valleys of the Transition zone, below 4500 feet elevation, arriving early in April, as shown by the above date, and by another record, April 9, 1911, at Helena, at an elevation of about 4000 feet. The other subspecies L. 1. migrans, is evidently a migrant only, occurring in the upper Transition zone, about 5000 feet elevation, in May.. The evidence to show this is certain only in the case of a bird taken at Anaconda, May 14,
