CHERR1E : ORNITHOLOGY OF THE ORINOCO REGION. 347 



Ciudad Bolivar, April 7, 1907. The nest was about 4.57 m. from the 

 ground at the extreme tip of a horizontal branch. of a scrub oak 

 (Chaparo} in a thinly wooded savanna region. It was not concealed 

 by foliage either from above or from below. Aly first impression on 

 seeing the nest was that it was a -slightly overgrown nest of a mock- 

 ingbird (Mimus). It is composed entirely of small dry twigs loosely 

 laid together. Outside it measures 12 cm. deep by 20 cm. in diameter 

 across the top. The saucer-shaped nest cavity is 5 cm. deep in the 

 centre, being unusually deep for the nest of a hawk. The outer edges 

 of the nest and the ground beneath it were white with excrement 

 from the incubating birds. The mother bird sat very close and did 

 not leave the nest until I had rapped the tree vigorously. 



The single egg which I succeeded in saving, is nearly elliptical, 

 being very slightly smaller at one end than at the other. It is a 

 glossless white, marked about the smaller end with large irregular 

 blotches of chestnut brown. It measures 29.5 x 24.25 mm. 



The juvenal plumage (downy young) is white below; above pale 

 vinaceous cinnamon, the wings being darkest and the neck and head 

 palest; there is a small dusty spot above the eye and the loral region 

 is dusky blackish. 



CERCHNEIS SPARVERIUS ISABELUNUS (Swainson). 

 Falco isabellinus Swains., Anim. in Menag. 1838. p. 281. 

 Cerchneis sparverius isabellinus Berlepsch, Ibis. 1884. p. 437 



(Angostura). 

 Tinnunculus sparverius isabellinus Berlepsch & Hartert, p. 114. 



Not uncommon. Observed at all points visited from Las Bar- 

 rancas in the delta region up as far as the falls of Maipures. 



Eye seal brown ; bill black at tip, plumbeous at base ; cere orange 

 yellow pfeet orange yellow, claws black. 



FALCO FUSCO-CAERULESCENS Vieillot. 



Falco fusco-caerulescens .Vieill., Nouv. Diet. XI. 1817. p. 90. 

 Hypotriorchis femoralis Berlepsch, Ibis, 1884. p. 437 (Angostura). 

 Hypotriorchis fuscocaerulescens Berlepsch & Hartert, p. 115. 



Not common. Not observed beyond the mouth of the Apure 

 River. Pairs hunt together, apparently aiding one another in the 

 capture of smaller birds. I have seen this species feeding on Campy- 



