36 TIMES OF MIGRATION 



September. The first marked fall in the temperature will be fol- 

 lowed by a flight of migrants which, because of the denser vegetation 

 and absence of song, are much more difficult of observation than in 

 May. Birds of the year, that is those born the preceding season, will 

 outnumber the adults, and in most cases their plumage will be quite 

 unlike that worn by their parents in May, while, in many instances, 

 even the adults themselves will appear in a changed costume. Often 

 this new dress will resemble that of the immature bird, a fact which 

 in part accounts for the apparent scarcity of old birds in the fall 

 migration. 



In September more migrating birds are killed by striking light- 

 houses or illuminated towers than in any other month of the year. This 

 is doubtless owing to the fact that stormy or foggy weather is more 

 apt to prevail in September than during any other period of active 

 migration; that the majority of migrants are young and inexperienced, 

 and that probably more migrants pass in September than in any other 

 month. It does not follow from this statement, however, that birds 

 may be so abundant on any one day as they are under certain conditions 

 in May, when, as before described, low temperature checks the north- 

 ward movement and causes an overflow. 



About September 25 the first winter residents arrive, and after that 

 date birds rapidly decrease in numbers. 



October. Early October generally brings the first killing frost, 

 causing the leaves to fall in fluttering showers and depriving many 

 insectivorous birds of their food and shelter. Flycatchers, Warblers, 

 Vireos, as well as Swallows, now take their departure, arid after the 

 fifteenth of the month few insect-eating birds remain, except those 

 which, like Woodpeckers, feed on insects' eggs or larvae. 



This is the season of Sparrows. In countless numbers they throng 

 old stubble, potato and corn fields, doing untold good by destroying 

 the seeds of noxious weeds. Song, Field, Chipping and Vesper Spar- 

 rows may be found in flocks, and with them will be the lately arrived 

 Juncos, Tree and Fox Sparrows. 



The diurnal migration of Crows and of Hawks, which in scattered 

 companies string across the sky, the foraging flocks of Grackles, and, 

 in recent years, the gatherings of European Starlings, are features of 

 the bird-life of the month. 



November. It is an interesting fact that the first migrants to come 

 in the spring are the last to leave in the fall. The bird-life of November, 

 therefore, closely resembles that of March. Doubtless this is because 

 both months furnish essentially the same kind of food. Thus Loons, 

 Grebes, Ducks, Geese and Kingfishers remain until November or 

 early December, when the forming of ice deprives them of food and 

 forces them to seek open water. Woodcock and Snipe linger until 

 they can no longer probe the frost-hardened earth; but the thaws of 

 March will bring all these birds back to us by restoring their food. 



December. The character of the bird-life of December depends 



