52 THEIR HABITAT. 



situated between the 40th degree of latitude and the 

 verge of the tropics, are their winter retreat. Nor 

 are they confined only to the Atlantic sea-board, 

 but are found in equally great numbers (as I have 

 learned from a close observer) on the Pacific margin. 

 However, they are not scattered like the mallard 

 (Anas boschas) all over this extensive region, but 

 confine themselves to certain localities. Thus, on the 

 great Western prairies, although on occasions I have 

 seen a flight of these birds, I have but seldom 

 killed them. On the harbours and bays of Northern 

 New England the sportsman rarely brings a num- 

 ber of canvas-back ducks to bay, yet they must 

 have passed over each of these extensive ranges in 

 their journeys from their breeding-grounds to their 

 winter quarters. Two reasons are urged to account 

 for this eccentricity or partiality. First, that the 

 intermediate space does not produce food suitable for 

 their support ; secondly, that their powers of flight 

 are so great that they almost disregard space. 

 Temperature, which operates so powerfully upon 

 nearly all aquatic fowls, as almost invariably to 

 force them to assemble in the greatest numbers 

 where the line of demarcation is drawn between frost 

 and thaw, does not in this particular case appear to 

 assert its influence in the same way, for without 

 resting, all, save the stragglers, pass from one region 

 to another, jumping as it were from hyperborean 

 latitudes to tropical climates. 



One peculiarity in the canvas-back duck must 



