342 BULLETIN 17 0, UNITED STATES NATIONAL MUSEUM 



J. Stuart Rowley writes to me that he took only one set of two 

 eggs of the dwarf horned owl, nearly ready to hatch, from a cavity 

 in a cliff at San Fernando on April 19, 1933. He found another nest 

 on May 8 in a crotch of an immense tree near Mira Flores. This was 

 apparently an old nest of Audubon's caracara; it contained one half- 

 grown young. 



Eggs. — The eggs of the dwarf horned owl are like those of the other 

 races but smaller, of course, than those of the larger races. The meas- 

 urements of nine eggs average 53.3 by 43.7 millimeters; the eggs show- 

 ing the four extremes measure 56 by 45.5 and 47.5 by 40.9 millimeters. 



Behavior. — Mr. Rowley says that the owls at San Fernando were 

 very shy, and he tried in vain to collect the parents of that set. The 

 female always left the nest as he approached by climbing over the 

 rocks where concealment was impossible. He witnessed on another 

 occasion an interesting performance, which he describes as follows: "I 

 was concealed near a pool of water, collecting nighthawks, when I saw 

 a horned owl perch on the top of a cardon, about 100 yards distant. 

 This individual, undoubtedly the male, started calling and in a few 

 minutes was joined by another bird, undoubtedly his mate, on the 

 top of another arm of the same cardon. The first bird continued his 

 hooting and proceeded to bow up and down in rhythm with each hoot, 

 accentuating the last hoot and bow of each performance. This lasted 

 for several minutes intermittently until I broke the silence of the 

 evening with a shot at a nighthawk, whereupon both owls left." 



BUBO VIRGINIANUS HETEROCNEM1S (Oberholser) 



LABRADOR HORNED OWL 



HABITS 



When Dr. Oberholser (1904) named this large, dark race of the 

 horned owls, he described it as "like Asio magellanicus saturatus, but 

 bill larger; posterior lower parts paler; feet lighter colored and less 

 heavily spotted; upper parts with usually less ochraceous. * * * 

 Although by authors heretofore referred to saturatus, the Labrador 

 bird differs from that form as detailed above, and its characters, 

 though not as strongly marked as are those of some of the other races, 

 are yet sufficient for recognition by name, particularly in view of a 

 widely separated range. Although, of course, nearest saturatus, the 

 differences may be readily appreciated in a good series." 



As birds from Newfoundland, of which we have a good series in 

 Cambridge, are not sufficiently different to warrant recognition in 

 nomenclature, Newfoundland is now included in the range of this 

 race, as are also northern Ungava and Nova Scotia. Dark-colored 

 horned owls, occasionally taken in winter in New England and 



