NUTTALL'S WHITE-CROWNED SPARROW 1315 



in those rare cases where death of white-crowned sparrows results 

 from his activities. 



There is direct evidence that snakes, hawks, and owls prey on 

 white-crowned sparrows. I have indirect evidence that shrikes, 

 jays, and crows are also enemies. Grinnell and Linsdale (193G) 

 found a 4-foot gopher snake in a bush with a nest of NuttalFs sparrows 

 and almost touching one of the two remaining young birds. The 

 same authors state that at Point Lobos Reserve sharp-shinned hawks 

 make frequent captures. Their account of one such capture states 

 that a hawk appeared from the pine woods, dashed down into the 

 radish patch where white-crowned sparrows were feeding, and cap- 

 tured a bird apparently of this species. Winsor M. Tyler (1923) 

 observed prairie falcons in the San Joaquin Valley and in the arid 

 hills along the western rim of this valley. "From the time the falcons 

 return to their nest cliffs in early spring through egglaying and 

 incubation periods the Gambel sparrows (Zonotrichia leucophrys gam- 

 belii) are very abundant in the regions where falcons abound and a 

 very heavy toll of these sparrows is taken." F. C. Evans and 

 J. T. Emlen, Jr. (1947) found the remains of crowned sparrows 

 (Z. leucophrys and/or Z. coronata) in barn owl pellets at Davis, Calif. 

 Albert C. Hawbecker (1945) found six white-crowned sparrow remains 

 in barn owl pellets at Struve Ranch near Watsonville, Calif. Herbert 

 Brandt (1951) mentions the northwestern shrike as being a predator 

 on GambePs sparrows, and I have occasionally found a shrike perched 

 on a trap where I was banding sparrows. I have seen jays and crows 

 watch me intently as I made trips to nests. At Friday Harbor crows 

 appeared to be chiefly to blame for destruction of the nests I was 

 watching that did not last through to the fledging of young. 



At Mountain Village weasels would undoubtedly have constituted 

 a danger to the ground-nesting Gambel's sparrows had not Eskimo 

 trapping kept their numbers to a minimum. In the 3 months I spent 

 at Mountain Village in 1950 I saw a weasel only once. I watched it 

 walk boldly along a path in full view to a point where two male 

 Gambel's sparrows were perched near the ground facing each other at 

 a territorial boundary. They were preoccupied with each other and 

 hence unaware of the weasel, which gazed intently at them and stayed 

 ready to spring as long as the birds remained near enough to the 

 ground to be almost within striking distance. As soon as the birds 

 flew off the weasel disappeared. At this locality jaegers that flew 

 over the tundra above the village seemed to watch me as I looked 

 for nests. As most of the Gambel's sparrows nested close to the village 

 where the jaegers came only rarely, these probably did not constitute a 

 great threat. At College most of the Gambel's sparrow nests I found 

 were at the edges of farmland, and I never saw an actual raid by a 



