THE FORMATION AND FLIGHT OF BIRDS. 205 



And next year with the same unfailing regularity 

 they collect and return to the land of their birth, 

 to mate, build nests, and rear young. 



Birds do Good. 



Almost all English birds do more good than 

 harm. Some species, of course, do more good than 



THE CUCKOO. 



others, and if any species that under ordinary 

 conditions do more good than harm be allowed 

 to multiply in too large numbers they will pro- 

 bably do more harm than good. 



