2(;G appendix, 



l)y the way for brief stojjs in places where food is abundant 

 and easily obtained. Under certain conditions, however, as 

 when crossing large bodies of water or regions scantily sup- 

 jtlicd Avith food, they are sometimes obliged to travel partly, 

 or pi'rhaps even exclusively, by night. Excellent examples 

 are the Kobin, Horned Lark, and most of the Oriole family. 



" Birds of easy, tireless wing, which habitually feed in the 

 air or over very extensive areas, migrate exclusively by day, 

 because, being able to obtain their usual supply of food as they 

 fly, or to accomplish the longest journeys so rapidly that they 

 do not require to feed on the way, they are under no necessity 

 of changing their usual habits. The best examples are the 

 Swallows, Swifts, and Hawks. 



" Nocturnal and crepuscular birds, at least migratory sjoecies, 

 are all strong-winged and accustomed to seek their food over 

 wide areas. Hence, like the Swallows, Swifts, and Hawks, 

 they migrate during the hours of their habitual activity. 



" The conclusions just reviewed will apply also to the wading 

 and swimming birds ; for their migrations, making due allow- 

 ance for the peculiar habits of certain species and groups, are 

 easily explainable by considerations either identical with, or 

 similar to, those above mentioned. 



"The Bittern, Woodcock, Wilson's Snipe, Spotted Sand- 

 piper, and the Eails without exception, migrate exclusively by 

 night. They are all sedentary birds addicted to feeding in 

 particular and usually limited areas, and all but the Spotted 

 Sandpiper seek safety in concealment. Accordingly, it is in 

 line with the previous reasoning that they should migrate by 

 night and rest and feed by day. The case is not, however, 

 exactly parallel with that of any of the land birds, for these 

 waders (except, perhaps, the Spotted Sandpiper) feed habitu- 

 ally more by night than by day. But all — even the Wood- 

 cock — also feed freely by day during the migrations. 



" The remainder of the wading and all the swimming birds 

 migrate indifferently by both night and day. This was to be 



