BIRDS OP THE CAMBRIDGE REGION. 363 



have been gone these many years." When this was written (in 1868) the colony 

 in the Stimpson barn was still populous and apparently flourishing, but it began 

 to decline soon afterwards and, if I remember rightly, was wholly broken up by 

 187s, although I am not quite sure that it did not continue to exist for a year or 

 two later. Since 1880 Barn Swallows have been steadily diminishing in numbers 

 throughout the Cambridge Region and at the present time only a very few 

 breeding colonies remain, although the birds are still common enough at their 

 seasons of migration, when they may be occasionally seen passing high in air over 

 our garden. They have long since ceased to appear there in May and June, or, 

 at any season, to glide low over the city streets and lawns after their old familiar 

 and delightful fashion. Had not their former nesting places under piazza roofs 

 and porches been wrested from them by the House Sparrows, it is probable that 

 at least a few birds would have continued to frequent even the more densely pop- 

 ulated parts of Cambridge. Their decrease in the country districts, however, is 

 evidently due chiefly if not wholly to another cause, viz., the very general substi- 

 tution of tightly closed barns and sheds of modern construction for the older-fash- 

 ioned buildings which were so generously ventilated, either through negligence 

 or by design, that the birds could enter or leave them at all hours of the day and 

 often by a dozen different openings at once. 



183. Iridoprocne bicolor (Vieill.). 

 Tree Swallow. White-bellied Swallow. 



Formerly an abundant summer resident, now comparatively seldom seen except during 

 migration when it is often rather numerously represented. 



SEASONAL OCCURRENCE. 



March 18, 1868, one seen, Fresh Pond Swamps, W. Brewster. 



April 5 — October 8. 

 October 17, 1878, one seen, Belmont, C. W. Townsend. 



NESTING DATES. 



May 20 — 30. 



-White-bellied Swallows were among the commonest and most familiar of our 

 summer birds before the English Sparrows came. I remember when the Swal- 

 lows bred numerously in or near the town centers of Belmont, Arlington, Lex- 

 ington, Waltham and Watertown, as well as throughout all of Cambridge and 

 even on Boston Common. In those happy days the number of birds was appar- 



