176 BULLETIN 196, UNITED STATES NATIONAL MUSEUM 



above sea level; the top of the mountain is covered with a wonderful 

 growth of red spruce in the seedling and sapling stages." 



Id northern Michigan, the breeding haunts of this thrush are some- 

 what similar to those in the east. Dr. Max Minor Peet (1908), 

 referring to Isle Koyale, says: "The damp places bordering streams 

 were a favorite resort, the birds being usually found on the lower 

 border of the balsam and spruce or among the decay-leaves aDd 

 rubbish at their bases. Owing to the dense shade the lowest branches 

 usually died and dropped off, so for a height of three to five feet it 

 was relatively open. It was this rather open, yet heavily shaded 

 condition which seemed to be best suited to these thrushes during 

 the breeding season. They were also found in the dense alder 

 thickets and resorted to the border of the woods and the roadside 

 during migration." 



In the Stikine River regioo of northern British Columbia, Mr. 

 Swarth (1922) found the olive-backed thrush breeding in quite 

 different surroundings. He says: "This is a bud of the poplar 

 woods and willow thickets of the lowlands, primarily, but we found 

 it also in small numbers well up the mountain sides. On July 17 

 Dixon saw several at the upper edge of the spruce timber (about 

 4,000 feet) on the mountains." But all the nests they found were 

 at the lower levels. Farther south, ia the Rocky Mountains, these 

 thrushes breed at higher elevations, 6,000 to 9,000 feet in Colorado. 



Spring. — In Massachusetts, the transient olive-backed thrushes 

 pass through during May or the first week in June. They come with 

 the warblers and other late migrants, and, like the warblers, they are 

 often seen in the tree tops, feeding on insects in the opening foliage. 

 They are not wholly confined to the woods at this season, but are 

 often seen in orchards, gardens, or parks, wherever there are trees 

 or shrubbery. 



The migration in Ohio is only slightly earlier, but the flight is 

 sometimes very heavy. Milton B. Trautman (1940) says that, in 

 the vicinity of Buckeye Lake, Ohio, "during the spring and fall 

 periods of maximum abundance between 40 and 300 individuals 

 could be daily recorded. Principally because of its large numbers 

 this was the most conspicuous of the thrushes, particularly in spring 

 when the males sang persistently. The Olive-backed Thrush in- 

 habited the shrub layer of swampy remnant forests. It was present 

 in small numbers about brushy fields, weedy aDd brushy fence rows, 

 edges of brushy swamps, cattail marshes, and shrubbery near farm 

 houses and cottages." 



There is a heavy migration, both spring and fall, across Lake 

 Erie, between Cedar Point, Ohio, and Point Pelee, Ontaiio, as de- 



