Townsend’s Solitaire is a nondescript gray bird, but is unlike any other in North America. Long and slender, with a long tail, buffy wingstripe, bold eye ring, and beautiful melodic song, it is one of the continent’s most underrated birds.
Solitaires nest on mountain slopes and subsist in winter largely on fruit, and they especially like juniper berries. Like many mountain nesters and like many frugivores, they are prone to somewhat irruptive winter-season movements. In some years, most birds will stay in the mountains, with relatively few descending to valleys and the western prairies. In other years, large numbers will come down to the lower elevations. It is important to remember that bird migration is not always a north-south movement (some birds, like Pigeon Guillemot and Heermann’s Gull, migrate north for the winter!), but can also be an altitudinal migration. The extent and variability of these patterns is yet another occurrence pattern that we are anxious to learn more about. The year to year variations are not being caught on this single year map, but it is a great view of how the mountain birds spread out through the Great Basin Desert and the western Great Plains in winter.
Try not to focus too much on their near “disappearance” in mid-summer. This relates to the period of low detectability that all birds go through after breeding, when they stop singing and get secretive while molting. Adjusting the scale would allow us too see that indeed these birds are still in those same nesting areas in August, even though many of the bright spots disappear from the map at that season.