COURTSHIP AMONG BIRDS 133 



obtain in the case, for example, of the Manakins. More 

 closely examined, however, this apparent failure of the 

 organism to produce its own mechanism becomes less 

 remarkable, for Woodpeckers are forest-dwellers and but 

 indifferent fliers ; loud sounds produced by the rapid 

 vibration of the wings or tail, as in the case of the Snipe, 

 in mid-air, are thus impracticable, if not impossible, 

 and sounds produced after the fashion of the Manakins 

 would not have sufficient carrying power. 



One of the most skilled performers among the 

 Woodpeckers is the Great Spotted Woodpecker (Den- 

 drocofus major)y whose weird drumming once heard will 

 never be forgotten. These sounds are produced by blows 

 of the beak on a branch, delivered so rapidly that the 

 bird's head presents but a blurred appearance. The 

 sounds thus made vary with the resonance of the wood 

 and can be heard at a distance of half a mile. These 

 strange vibrating notes are most frequently heard during 

 the courting season, and they will commonly beget a 

 speedy response from some more or less distant part of 

 the wood, so that their purpose is clear. They attain 

 the same end as the bellowing of the stag or the " lek " 

 of the Capercaillie. They are, however, to be heard at 

 other times, as when the birds are greatly alarmed or 

 when the nest is being robbed. 



