CALIFORNIA FISH AND GAME 35 



In Trinity County durinf? 6^ months time on 104 square miles, 

 1347 miles of trap line was run to ea])tui-e 10 coyotes or an average of 

 one coyote to 10.4 square miles ; and one coyote to 134.7 miles of trap 

 line. A total of 3958 sets were exposed or an average of 395.8 sets 

 per coyote. 



This summary shows something of the relative abundance of 

 coyotes in the various refuges. 



Bobcats were most numerous in San Benito and Lake counties. 

 In the Coast Range, coyotes and bobcats are practically resident 

 wherever found, not migrating perceptibly. In the Sierras the seasonal 

 migration of coyotes is east and west. The summer resident coyotes 

 at high elevations drop down replacing those at a lower level, which 

 in turn move down replacing others until there is a greater or less 

 movement into the valleys. This migration begins at approximately 

 the time sheep are moved from their summer range. The upward 

 migration follows the receding winter and possibly the spring herding 

 of sheep to the summer range. After winters of heavy snow in which 

 many deer are killed, these coyotes find a bounteous food supply. 



In the Pinnacles region of San Benito County where the coyotes 

 are mostly resident, the best catches of coyotes were made when sheep 

 were concentrated in a relatively small area. Trapping became poorer 

 when sheep ranged over greater areas in the spring. In Kern County 

 on IM very few coyotes were taken on the refuge when the sheep had 

 been moved to the valley ranges. From the information at hand, the 

 movement of sheep has a greater effect on the abundance of coyotes 

 in a given locality than any other factor. 



Trapping on certain areas did not prove worth while. The Gray 

 Lodge Refuge in the Sacramento Valley north of Marysville Buttes 

 at an elevation of 60 feet, is a good example. No coyotes were secured 

 in 38 days of trapping, with 25 miles of trap line each day, and an 

 average of 30 sets per day. 



Refuge IG in Tehama County was not satisfactory possibly because 

 of private trapping to the west on the wintering ground. 



Part of 1-0 in El Dorado County in the drainage basin of Big 

 Silver Creek and its middle fork did not produce a coyote during a 

 month's trapping in July when coyotes should have been in that region. 

 No signs of coyotes were in evidence. A total of 393 miles of line 

 with 659 sets were exposed during the month. 



The Mount Hamilton region is interesting because in the refuge, 

 which includes the mountain above the 2200-foot contour, practically 

 no bobcats or coyotes are found at any season, while around the base 

 of the mountain below the refuge they are not uncommon. 



It is impossible for coyotes and bobcats to be numerous beyond 

 their food supply. When the population reaches the point where the 

 food begins to decrease, then the predators must decrease. The coyote 

 is dependent to a large extent on rabbits and squirrels, and w'here 

 coyotes are plentiful, as in San Benito County, squirrels and rabbits 

 are also numerous. Although quail are particularly abundant (more 

 than 300 were seen per day) in all parts of that area trapped, only 

 one coyote out of 175 had quail remains in its stomach. Only two 

 coyotes out of 563 trapped, in this study, had quail remains. 



In this same region in San Benito County wood rats, which are 

 the bobcat's mainstay, are fairly plentiful and we found bobcats were 



