North American Fauna No. 27, U. S. Dept. Agr. Biological Survey. 



Plate XXIII. 



Fig. I.— Nest and Eggs of Arctic Great Horned Owl 



(BUBO V. SUBARCTICUS). FORT SIMPSON, APRIL 22, 1 904. 



Fig. 2.— Clustered Nests of Cliff Swallow (Petrochelidon lunifrons) Near 

 Lake Hardisty (North of Fort Rae>, Latitude 65 



