358 THE SWIFT 



collects seeds, and uses its saliva to fashion therewith a nest over 

 two feet in length. This remarkable nest-bag is hung from the under- 

 surface of a rock. Lastly, the esculent-swifts build their nests often 

 entirely of saliva, and attach them to the walls of caves, whence they 

 are torn to provide the well-known bird's-nest soup of the Chinaman. 



Both sexes share in the work of construction, but how long it 

 usually takes to complete is not recorded. The hen appears to be alone 

 responsible for incubation. The cock contents himself with bringing 

 her an occasional meal, and spends most of his time in riotous living 

 with his fellows, a fact noted long ago by the discriminating eye of 

 Gilbert White : " On hot mornings several, getting together in small 

 parties, dash round the steeples and churches, squeaking as they go 

 in a very clamorous manner : these, by nice observers, are supposed 

 to be males, serenading their sitting hens ; and not without reason, 

 since they seldom squeak till they come close to the walls or eaves, 

 and since those within utter at the same time a little inward note 

 of complacency." 1 This is not the only form of play indulged in by 

 swifts. Sometimes one bird pauses in flight and clings to a wall. 

 Its fellows pull him away, and off they all go screeching in a follow- 

 my-leader chase, each trying to buffet the one in front. If one slips 

 into his nest-hole, the others pause a second to scream remarks out- 

 side, complimentary or otherwise, and then pass on. And as they 

 flash by each nest, the sitting hen sends after them a sympathetic 

 scream of excitement. 2 It has been often observed that in these 

 chases the course is always in one direction, never varying. The call 

 to take part in the game is quite distinguishable from the other 

 squealing notes uttered by the bird. 8 



The hens occasionally issue from their nest to feed or stretch their 

 wings. This they often may be seen doing in the evening, and are indeed 

 tempted to delay the return to their duties until driven home by the 

 cocks, who follow, with scolding notes, each turn and twist of their 



1 Letter to Harrington, September 28, 1774. 2 Nature Notes, 1891, 07-00 (Aubrey Edwards). 

 3 P. C. B. Jonrdain (in litt.) 



