FAMILY ACCIPITRIDAE I75 



ELANOIDES FORFICATUS YETAPA (Vieillot): Swallow-tailed Kite; 

 Gavilan Tijereta 



Figure 35 



Milvus yetapa Vieillot, Nouv. Diet. Hist. Nat., nouv. ed., vol. 20, May 30, 1818, 

 p. 564. (Paraguay.) 



The long, deeply forked tail identifies this species at a glance from 

 any other hawk. 



Description. — Length 500 to 630 mm. Adult, wing coverts and 

 back very dark green; outer scapulars, wings, and tail dark gray, 

 the longer feathers with a greenish sheen ; inner scapulars, head, 

 neck, and whole of under surface, including the under wing coverts, 

 pure white. 



Immature, head and upper breast streaked narrowly with blackish 

 brown. 



Measurements (From Friedmann, U.S. Nat. Mus. Bull. 50, pt. 11, 

 1950, p. 90).— Males, wing 405-447 (418), tail 298-330 (318), culmen 

 from cere 19-20 ( 19.6) , tarsus 31.5-33.0 (32.4) mm. 



Females, wing 390-427 (411), tail 275-326 (304), culmen from 

 cere 19.5-21.0 (20.2), tarsus 32.0-33.5 (32.3) mm. 



Found throughout the Republic in the tropical and lower subtropical 

 zones, where it nests ; fairly common. Possibly migrant in part after 

 breeding, but from present information this is not certain. 



These are birds of graceful, soaring flight that remain for long 

 periods on the wing. Though they eat lizards, and are reported to 

 take birds, nestlings, and eggs, they also feed extensively on insects 

 of a considerable variety of kinds. Skutch (Condor, 1965, p. 236) 

 saw them eating small insects which they captured in their feet while 

 on the wing. As the kite continued to circle it lowered the head and 

 brought the foot forward to place the small morsel of food in its 

 mouth. 



The eggs of the swallow-tailed kite, with smooth shell, are white to 

 creamy white, marked with dark brown or chestnut in an irregular 

 pattern that varies from fine spots to heavy blotches. Two eggs consti- 

 tute the usual set, though 4 have been recorded. Schonwetter (Handb. 

 Ool., pt. 3, 1961, p. 154) records the measurements of 4 of this race 

 as 45.1-47.4x35.0-37.1 mm. One in the U. S. National Museum 

 received from Col. L. R, Wolfe, collected in Sucre, Venezuela, April 

 24, 1935, is elliptical in form, and in color faintly creamy white, heav- 

 ily marked with brown. It measures 47.9 X 39.5 mm. 



