FAUNA OF THE ALEUTIAN ISLANDS AND ALASKA PENINSULA 297 



the shoreline, and there are few land birds. The sea birds depend 

 on the ocean for food and generally are found at, or near, the 

 shores. The life-giving tides are the principal source of food. 

 There are no native rodents west of Umnak, but ground squirrels 

 have been placed on Kavalga for fox food, and rats accidentally 

 were introduced on Rat Island in early days. Foxes feed on both 

 of these animals, 



On Rat Island, 28.8 percent of fox droppings contained rats, 

 and about 40 percent contained beach fleas. Rat Island has ex- 

 tensive beaches, and most of the rats are confined to the beaches 

 because of the nature and distribution of the vegetation. 



Rats have also been introduced on Atka and are eaten by foxes, 

 but our data for that island are too meager for tabulation. On 

 Unalga Island, in the Fox Islands group, blue foxes were feeding 

 on field mice, but these rodents are not available on most of the 

 Aleutians. 



A stranded whale, or a dead seal or sea lion, often becomes an 

 important item of fox food. We witnessed a whale being eaten on 

 Yunaska Island, but a whale on the beach of Kanaga was hardly 

 touched — this was explained by the caretaker who stated that 

 most of the foxes were on the other side of the island. 



The importance of birds in the blue fox diet is evident in the 

 tabulation. In the Aleutians as a whole, they furnish 57.8 per- 

 cent of the food, though the percentage varies on different islands, 

 depending on availability. Land birds are relatively unimpor- 

 tant. They are hard to capture and do not gather in large groups. 

 But the concentrated colonies of petrels, auklets, and related 

 species furnish rich hunting grounds. In addition to the droppings 

 tabulated in table 1, for Kasatochi Island, we found a single 

 fox cache under a rock that contained 65 crested auklets, 37 least 

 auklets, 1 whiskered auklet, 1 parakeet auklet, and 1 pigeon 

 guillemot, and there were more birds farther back under the 

 rock. On Bobrof Island, we found remains of 103 petrels, 6 

 tufted puffins, 4 least auklets, and 1 pigeon guillemot. On Semi- 

 sopochnoi, we listed remains found at dens as follows : 107 least 

 auklets, 18 crested auklets, 3 tufted puffins, 1 horned puffin, 1 

 murre, and 7 fork-tailed petrels. 



Necessarily, insects are a minor item in the diet, yet it is in- 

 teresting to note that of the 10 droppings from Kiska Island that 

 contained larvae of Noctuidae, one dropping consisted of 50 per- 

 cent, another 75 percent, of these caterpillars. 



There is an interesting item from Kagamil Island. Two drop- 

 pings contained skin from Aleut mummies. When we examined 



