320 FIELD, FOREST AND FARM 



swallow. When once the date has been fixed, the 

 window-swallows gather together daily for several 

 days on the roofs of tall buildings. Every few min- 

 utes small parties detach themselves from the gen- 

 eral conclave and circle about in the air with anxious 

 cries, taking a parting look at their native haunts, 

 and paying them a last farewell. Then they return 

 to their places among their companions and join in 

 noisy chatter on the subject of their hopes and fears, 

 all the while preparing themselves for the distant 

 expedition by a careful inspection of their plumage 

 and a final touch to one lustrous feather after an- 

 other. 



"After several repetitions of these farewells a 

 plaintive twittering announces the fateful hour. The 

 moment has come, it is time to start. The flock rises, 

 the emigrants are off for the south. If one of them 

 has been marked with a red string around the claw 

 in order to be recognized, you may be sure you will 

 see it come back the next spring and take possession 

 of its nest again with little cries of joy at finding it 

 intact and ready for occupancy after a few repairs. 



"With their vigorous wings the duck and goose, 

 in their wild state, are ardent travelers. On a gray 

 day in November, when there are signs of snow, it 

 is not unusual to see passing from north to south, 

 at a great height, birds arranged in single file, or in 

 a double file meeting in a point, like the two branches 

 of the letter V. These birds are a flock of either 

 ducks or geese in the act of migrating. 



"If the flock is of no great size, the birds compos- 



