BIRDS OF THE CAMBRIDGE REGION. 59 



As might be expected, the common summer birds of the Cambridge Region, 

 ahiiost without exception, belong to species which breed more or less generally 

 throughout the Transition Life Zone. Of the rarer summer birds the Acadian 

 Owl, Olive-sided Flycatcher, Alder Flycatcher, Pine Linnet, Solitary Vireo, 

 Blackburnian Warbler, Canadian Warbler, Brown Creeper, Red-bellied Nuthatch, 

 and Hermit Thrush, belong more properly to the Canadian and Lower Canadian 

 Zones, and the Least Bittern, Florida Gallinule, Orchard Oriole, Cardinal Gros- 

 beak, Black-throated Bunting, Yellow-breasted Chat, Mockingbird, and Carolina 

 Wren, to the Upper Austral Zone. Most of the birds included in the latter 

 class appear to confine their visits to the eastern portions of the region, where 

 the country is low and bordering on tide-water, while of the Canadian or Lower 

 Canadian forms the Alder Flycatcher, Blackburnian Warbler, Canadian Warbler, 

 Red-bellied Nuthatch and Hermit Thrush have been found in summer only in 

 the hilly central or western portions. The Olive-sided Flycatcher and Pine 

 Linnet, however, are known to have bred within the present limits of the City of 

 Cambridge, and the Solitary Vireo and Brown Creeper have been seen there in 

 early summer. 



It is a well-established fact that a large proportion of the smaller migratory 

 birds, which pass and repass through eastern Massachusetts on their way to and 

 from more northern breeding stations, follow lines of flight which border closely 

 on the seacoast. Lying, as it does, very near the coast, the Cambridge Region 

 (especially throughout its more eastern portions) is much better supplied with 

 bird life in spring and autumn than are localities further inland. In May, when 

 the heaviest flights are passing northward, and in late August and early Septem- 

 ber, when the return movement is at its height, our woods and thickets are ten- 

 anted, often for days in succession, by a fairly bewildering number and variety of 

 Warblers, Sparrows and other small ' birds of passage,' as they used to be called. 

 Of these transient visitors the Lincoln's Sparrow, Orange-crowned Warbler and 

 Connecticut Warbler are especially interesting for the reason that they have 

 been found more numerously and regularly in and about Cambridge than else- 

 where in eastern Massachusetts. 



In winter, also, our region is especially favored by the smaller birds. 

 Besides the species regularly found at that season throughout most of the State, 

 such as the Quail, Ruffed Grouse, Red-shouldered Hawk, Screech Owl, Hairy 

 Woodpecker, Downy Woodpecker, Blue Jay, Crow, Goldfinch, Snow Bunting, 

 Tree Sparrow, Junco, Brown Creeper, White-breasted Nuthatch, Chickadee and 

 Golden-crowned Kinglet, we are nearly sure to note those irregular visitors, the 

 Pine Grosbeak, the two kinds of Crossbills, and the several forms of Redpolls, 

 whenever they invade any part of eastern Massachusetts. Of the species which 

 winter chiefly near the coast or only in places where food is particularly abundant, 



