iSoi I Loomis on Birds of Chester Comity, South Carolina. IO^ 



food on the ground and not to inability to withstand the cold. 

 Likewise I would account for the fluctuations in this region in the 

 Prairie Horned Lark — snow further north sending them south 

 when the increase occurs simply with cold. The American 

 Pipit endures the severest cold of this region without migrating 

 when the ground is bare, but when it is covered with snow they 

 entirely disappear, immediately reappearing, however, with the 

 disappearance of the snow. At Caddo, Indian Territory, in the 

 winter of 1SS3-84 no Lapland Longspurs were seen until a 

 sudden cold turn in February covered everything with frozen 

 rain. Then they fairly swarmed for a week ; at its end, "taking 

 advantage of a clear sky and a south wind, they disappeared, in 

 company with all their long-clawed brethren, as suddenly as 

 they had come" (Rep. Bird Migr. Miss. Vail., p. 1S5). 



Rapacious species naturally follow the vegetivorous species 

 southward, and this, together with the covering up of other 

 sources of food, seemingly explains the inroad of Red-tailed 

 Hawks in the winter of 1SS6-S7 (Auk, IX, p. 30). Warmth 

 simply opens the way for northward migration. The failure 

 of the Palm Warblers to appear when the Pine Warblers 

 responded to the genial weather of December, 18S9 (Auk, IX, 

 pp. 28, 29) was, perhaps, partly due to the location of the 

 winter isolated communities and partly to the main movement 

 passing to the westward, as the species is much less abundant 

 in spring than in fall. Besides failure from the covering up of 

 the sea by ice there is said to be failure of food also at the north 

 through the descent of certain marine forms of life to the lower 

 depths, resulting in the migration of other forms — the dearth of 

 the land through checking of vegetable and animal life by cold 

 thus finding a parallel in the sea. 



To sum up : It seems that cold in the winter migratory move- 

 ments is but the remote cause, failure of food being apparently 

 the immediate cause. Autumn movements within the bounds 

 of winter habitat, as in the Mockingbird, seem to be anticipatory 

 of failure of food, the cold simply warning dilatory migrants that 

 the season of abatement in food has really come. 



Variability in the occurrence of winter residents attributed to 

 failure of food independent of sudden cold should be considered 

 at this point. In studying southward migration at the southern 



«4 



