502 HISTORY OF THE 



as to cause a hasty retreat of even the largest birds of prey. 

 They are, therefore, of great value in the protection of poultry. 

 Like all of the family, they feed exclusively upon the wing, 

 swiftly gliding here and there in their search for insects the 

 larger ones, especially beetles, are the favorites. A pretty sight, 

 as they dart and flit swiftly, or sail slowly, at times a mere speck 

 in the sky; at others, near the ground or surface of the water, 

 skimming so low as to often bathe their breasts and snap up 

 with their bills a cooling drink. They are noisy, chattering 

 birds; the first to awake us in the morning with twittering notes. 



Their attempt at song, though not musical, is quite pleasing. 

 Preparatory to leaving in autumn, they assemble in large flocks, 

 and rest for several days upon the ridges of the highest build- 

 ings or dead trees, putting in a large share of their time in dress- 

 ing or oiling their feathers, and in chattering away in regard to 

 the contemplated movement; occasionally, as of one accord, 

 dash off together for a short distance, and then slowly return to 

 their resting places, as if practicing for the journey. When all 

 are ready, they wing themselves away, usually at night, in a com- 

 pact body, and almost with the speed of an arrow. 



Their nests are composed of various materials, loosely thrown 

 together, such as dry grasses, straws, leaves, bits of rags, strings, 

 etc., and warmly lined with feathers. Eggs four to six, .97x.70; 

 creamy white; in form, oval to ovate. 



GENUS PETROCHELIDON CABANIS. 



"Bill stout and deep, somewhat as in Progne. Nostrils entirely superior, 

 open, without overhanging membrane on the inner (or upper) side, but some- 

 what overhung by short bristles seen also along base of inner mandible and 

 chin. Legs stout, the tarsi short, not exceeding the middle toe exclusive of its 

 claw; feathered all round for basal third or fourth, though no feathers are in- 

 serted on the posterior face. Tail falling short of the closed wings; nearly 

 square or slightly emarginate; the lateral feathers broad to near the ends, and 

 not attenuated." 



Petrochelidon lunifrons (SAY). 



CLIFF SWALLOW. 

 PLATE XXX. 



Summer resident; locally abundant. Arrive the last of April; 

 begin laying about the middle of May; leave the last of August 

 to middle of September. 



