BIRDS IN FLOCKS 77 



break up for the nesting-season. In most years starlings 

 are paired and distributed in their breeding-places by early 

 April ; but after the heavy snowfall at the end of April 

 1908 huge evening flocks were still to be seen in the first 

 week of May, when all the spring flowers were coming out 

 together in the sudden warmth. 



Rooks congregate in their winter roosting-places about 

 the same time in autumn as the starlings, but in much smaller 

 numbers. The dignified passage of seven or eight hundred 

 rooks across the sunset sky has a very different kind of in- 

 terest from the rallying of the starlings. There is something 

 overwhelming and almost appalling in the starlings' enormous 

 hosts ; but the rooks' flocks are large enough to be impres- 

 sive, without verging so uncomfortably upon infinity. After 

 the end of May, when the young are fully fledged, rooks 

 often desert their rookeries more or less completely, and for 

 the rest of the summer choose other quarters, where they 

 roost in fair-sized flocks. In September or early October 

 they collect for the night in larger bodies in a roost which 

 is often chosen in a large and sheltered wood. Hencefor- 

 ward, until the beginning of the nesting-season, their daily 

 movements have almost the regularity of the sun. Soon 

 after it is light they can be seen passing high overhead to 

 their feeding-grounds on some broad belt of cultivated land ; 

 and while the sunset sky is still red, they troop home again on 

 the same steady path. Their movements before settling to 

 roost are often much like those of the starlings, but are less 

 remarkable and defined. They collect with busy clamour in 

 the trees or on the grass not far from the roost, and some- 

 times plunge to the tree-tops in the same remarkable flight. 

 Starlings roost alone in their great winter congregations ; 

 but rooks often forgather with jackdaws and sometimes 

 with smaller and more stationary parties of starlings which 



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