The Audubon Societies 



121 



or even from Patagonia, and they still have several thousand miles to go, so that, before 

 they reach their nesting-grounds again, they will have traveled 16,000 miles since leaving 

 in the fall. The 'champion long-distance migrant' of them all, however, is the Arctic 

 Tern, the extremes of whose nesting and wintering ranges are 11,000 miles apart, so 

 that they have to travel 22,000 miles each year. 



This constrains us to wonder how these tiny wayfarers are able to travel such trem- 

 endous distances and still return so accurately to their homes. That many of them do 

 this has been proved by placing aluminum bands on their legs, so that they can be 

 recognized from year to year. Not only has this been demonstrated, but it has likewise 

 been shown, in the same way, that many birds spend the winter in exactly the same 

 place year after year. 



At one time it was thought that they followed well-marked highways in the moun- 

 tains, rivers, and coast-lines, surveyed, as it were, by their ancestors and unfailingly 

 followed by all descendants. But now it is believed that these highways are followed 

 only so far as they afford abundant food, and when the 



food-supply lies in some other direction, they are regard- -^"^ "V i, 



lessly abandoned. What is it, then, that guides them mile .^ , C^/;-", 

 after mile in their flights, flights made mostly under the ^ ) ' ' • X. 



cover of darkness, and often at altitudes varying from ^ < . ■> 



2,000 to 5,000 feet above the earth? A sense of direc- ' "■■''/ 



tion, it is now called, an instinct for recording directions ^ ~ 

 as accurately as a compass, which we, having only so 

 crudely developed in ourselves, are at a loss to under- 

 stand; an instinct which permits birds to travel north, 

 south, east, or west and not lose their bearings. For the 

 migration route of most birds is not directly north and 

 south, and many preface their southerly journeys by long 

 flights directly east or west. The Bobolinks and Vireos 

 of the northwestern states, for example, leave the country 

 by way of Florida or the Gulf Coast, and first fly directly 

 east to the Mississippi Valley, to join the others of their 

 kinds before starting southeasterly. The White-winged 

 Scoters, which nest about the lakes of central Canada, 

 upon the completion of their nesting duties, fly directly 

 east and west to the Atlantic and Pacific where they 

 winter. Some Herons preface their migrations by long 

 flights, even to the north, so that occasionally Little Blue 

 Herons and Egrets are found in the northern states during August and September. 



With birds that travel such enormous distances, it is interesting to note their rate 

 of advance. While it is possible for birds to travel great distances without a rest, as 

 witnessed by the fall flights of the Turnstone from Alaska to Hawaii, or of the Golden 

 Plover from Labrador to northern South America, distances of over 2,000 miles across 

 the open sea, they do not ordinarily progress far in single flights. The spring advance of 

 the Robin, for example, averages only 13 miles a day from Louisiana to southern Minne- 

 sota. The rate increases gradually to 31 miles a day in southern Canada, 52 miles per day 

 by the time it reaches central Canada, and a maximum of 70 miles a day when it reaches 

 Alaska. It should not be inferred from this that each Robin does not ever migrate less 

 than 13 or more than 70 miles a day. Probably they often fly more than a hundred or 

 two hundred miles in a single flight, as do, undoubtedly, many of the smaller birds, but 

 after each flight they dally about their resting-place for several days before starting on 

 again, and this brings down the general rate of advance. 



The rate of speed at which birds travel is rather difficult to estimate, except in the 



MIGRATION OF THE 



ARCTIC TERN (From Cooke) 



The extreme summer and winter 



homes are 11,000 miles apart 



