64 MEMOIRS OF THE NITTTALL ORNITHOLOGICAL CLUB. 



assumed, do exiled birds return to their favorite summer ranges when a period 

 of congestion there is succeeded by one of temporary scarcity. In February, 

 1895, immense numl)ers of northern-breeding Bluebirds perished from cold and 

 starvation while at their winter homes in the South. It is probable that the loss 

 represented fully eighty per cent of the total numbers of the species. When 

 the survivors came north the next spring they did not spread out evenly over all 

 the region usually inhabited by Bluebirds ; on the contrary they occupied only 

 what were evidently in their eyes its- choicest portions. In some areas they 

 were as numerous as ever that first season ; in others only a few were seen ; in 

 still others of great extent they were wholly absent. The rapidity with which 

 they increased at the stations chosen, and from them repopulated their former 

 haunts, was simply astonishing. Indeed by the end of the next six or seven 

 years they were as numerous and generally distributed as ever. It is probable 

 that Bluebirds, as well as Robins, usually maintain their numbers at near the 

 maximum limits, for they are exceptionally prolific and hardy birds. 



I have said that exiled birds return to their favorite summer haunts when- 

 ever the congestion there is ended. It is probable, however, that this rule is not 

 without exceptions. Indeed there are good reasons for believing that when the 

 exiles form new colonies in localities or regions which prove well suited to their 

 tastes, they sometimes occupy them permanently. From such outlying stations 

 there are also, no doubt, occasional overflows into neighboring and perhaps 

 less congenial territory. Thus the scattered pairs of Yellow-breasted Chats 

 which, from time to time, have been found breeding in the Cambridge Region, 

 have probably come from the long established and formerly flourishing but iso- 

 lated colonies in Lynn and Swampscott. 



At the time when the Black-throated Buntings invaded eastern Massachu- 

 setts in numbers, they bred regularly and abundantly in the Middle States, 

 from which, doubtless, they spread northward, but throughout which they have 

 since practically disappeared, although they are still numerous enough in certain 

 parts of the Mississippi Valley. I believe that they were originally confined 

 to the treeless portions of this valley and that they did not extend their range 

 eastward until the heavy forests of the Ohio Valley and the Middle States were 

 largely replaced by fields of grass or grain. If this were so, they have simply 

 returned to their normal habitat, no doubt because their numbers are not at 

 present sufficient to enable them to occupy the Atlantic Coast region also. It 

 is not probable that we shall again see them commonly in New England until 

 they have repopulated the Middle States, which, of course, they may never do. 

 In other words there is not likely to be a sudden and direct overflt)w from the 

 Mississippi Valley to a region so distant from it as New England. 



