152 BIRDS 



powerful flight, sometimes covering a thousand miles in 

 twenty-four hours, it is said, and never resting except in its 

 roosting places (hollow trees or chimneys of dwellings), 

 where it does not perch, but rather clings to the sides with 

 its sharp claws, partly supported by its sharper tail. 

 Audubon tells of a certain plane tree in Kentucky where he 

 counted more than nine thousand of these swifts clinging 

 to the hollow trunk. 



Old-fashioned swifts still nest in hollow trees or caves, 

 but chimneys are so much more abundant and convenient, 

 that up-to-date birds prefer them. Without stopping in 

 their flight, the parent swifts snap off with their beaks or 

 feet httle twigs at the ends of dead branches, and these 

 they carry, one by one, into a chimney, gluing them against 

 the side until they have finished an almost flat, shelf -like 

 lattice cradle. Where do they get their glue? Only during 

 the nesting season do certain glands in their mouths secrete 

 a brownish fluid that quickly gums and hardens when ex- 

 posed to the air. After nursery duties have ended, the 

 gland shrinks from disuse. When the basket has been 

 stuck against a chimney-side, it looks as if it were covered 

 with a thin coat of isinglass. On this lattice from four to 

 six white eggs are laid. Mid-summer fires on the hearth 

 sometimes melt the glue when "down tumble cradle and 

 babies and all." 



When the baby swifts are old enough to climb out of the 

 lattice, they stiU cling near it for about a fortnight waiting 

 for their wings to grow strong before they try to leave the 

 chimney. Apparently they hang themselves up to go to 

 sleep. Doubtless they would fall but for their short, thin, 

 stiff-pointed tail feathers which help to prop them up where 

 they cling to the rough bricks and mortar of the chimney 



