Desert Sparrow Hawk and Pasadena Screech Owl in the Same Nest
Desert Sparrow Hawk and Pasadena Screech Owl in the Same Nest
A Pasadena Screech Owl (Otus asio quercinus) was found in an old hole up ten feet in a dead Joshua tree stump on the Mohave Desert north of the San Bernardino Mountains. Ten inches down from the opening, on dead wood chips, there were two fresh eggs of the owl. A week later, on April 16, 1939, a Desert Sparrow Hawk (Falco sparverius phalaena) was flushed from this hole and investigation disclosed that the nest contained the two owl eggs and three eggs of the hawk, one being a runt of about onethird normal size. An owl, probably the owner of the two eggs, was in another hole about one hundred feet away, incubating a single egg of her own. On April 23 the original hole was still in the possession of the hawk and contained an additional egg of the hawk; the owl had deserted her egg. The hawk must have believed “a turn about is fair play” for in 1935 (Condor, vol. 38, 1936, p. 250) I found in this same vicinity an owl in possession of a mixed Set.
Wilson C. Hanna
Colton, California, February 24, 1940
