The Marsh Is a Hotel 25 



on their way again. Only a minute fraction of one per cent 

 would remain, as summer residents of the area, and to mate 

 and raise their young. All the rest were northward bound 

 except a few, such as the varied thrushes, which spent the 

 winter in the valleys and in spring flew to their nesting 

 grounds in the higher elevations of the mountains. 



In these days when the word "millions" is mentioned so 

 often I thought it strange that little attention had been paid 

 by the public to this migration movement which involves 

 more than a billion living creatures. It is a remarkable exam- 

 ple of natural logistics— this moving and feeding and shelter- 

 ing of millions of birds. They must be provided with suitable 

 nesting grounds and returned safely to their winter quarters. 

 The operation involves four phases: the wintering; the trip 

 to the breeding grounds; the courtship, mating, and care of 

 the young; the return journey of the old and the young birds. 



The operation must be precision-executed so that every 

 detail will come off on schedule. The nesting must not be 

 done so early that the young will hatch before suitable food 

 is available. It must not be done so late that the growth and 

 flight training cannot be completed before the fall storms. 

 The return limits are therefore quite inflexible, especially in 

 the districts farther north. Nothing can be left to individual 

 chance: each bird must be filled with a stimulus which will 

 give it the irresistible urge to leave the winter grounds and 

 to start at the proper time on the long journey to the place 

 where the courtship, mating, and reproduction are concen- 

 trated in one short season— a journey which, for a few birds, 

 involves the length of two continents. Many of the birds 

 which came to the marsh in this season wore breeding plum- 

 age, and the males, in particular, were brilliant and splendid 

 in gay colors acquired especially for the occasion. The black- 

 bellied plover made its spring passing in a formal black and 

 white, and the horned grebe, gray and inconspicuous at other 

 times of the year, appeared in rich and dark red plumage 



