National Geographic Magazine/Volume 31/Number 4/Friends of Our Forests/Macgillivray Warbler
The Warblers of North America
editCONNECTICUT WARBLER
MOURNING WARBLER
MACGILLIVRAY WARBLER
Range: Breeds mainly in the lower Canadian and Transition Zones from central British Columbia, central Alberta, and southern Saskatchewan south to southern California, southern Arizona, and northern New Mexico, and from the Pacific coast to the eastern foothills of the Rocky Mountains and southwestern South Dakota; winters from Lower California to Colombia.
Though closely resembling the mourning warbler in appearance and representing that bird in the west, the Macgillivray warbler differs widely in habits. Thus it is far more generally distributed, both in the mountains and in the lowlands, and is much more numerous. In my own experience I have found it in summer chiefly in moist thickets of willows or other brush along streams, and a suitable locality is rarely without a pair or two. Other observers, however, have found the bird on dry brushy hillsides. This warbler nests from a few inches to a few feet above the ground. It has a short, though pleasing, song which is repeated at brief intervals.
Source: Henry W. Henshaw (April 1917), “Friends of Our Forests”, The National Geographic Magazine 31(4): 321. (Illustration from p. 320.)