FUR SEAl^ AND OTHER LIFE, PRIBILOF ISLANDS, I914. 19 



spring months are spent entirely at sea. The migration route in general is southward 

 to the passes of the Aleutian Islands, then eastward and southeastward along the coast 

 of Alaska, British Columbia, and the United States to the latitude of southern Cali- 

 fornia. The adult males remain farthest north, wintering south of the Aleutian Chain 

 and in the Gulf of Alaska. The younger males go somewhat farther and the females 

 the farthest of all. Returning from their winter resort, the seals reach the islands in 

 general according to their age, the older animals first and the youngest last. The 

 adult males begin to reach the Pribilof Islands about the ist of May; the adult females 

 and the older bachelors arrive there mainly in June; the 2-year-olds mainly in July; 

 and the yearlings in the latter part of August and early September. 



BREEDING HABITS. 



On reaching the islands the old bulls at once take their places on the rookery ground, 

 in many cases, perhaps in most, choosing the same spot occupied in former years. They 

 remain on the place selected throughout the entire breeding season without eating. Once 

 the place is chosen they can scarcely be forced by any means to forsake it, and display 

 the most extraordinary courage and persistence in maintaining their position against the 

 assaults of their rivals or the efforts of man. During May and June the numbers on 

 the rookery increase, each bull on arriving taking such place as he can obtain, some- 

 times by dispossessing another, but as a rule by selecting an unoccupied spot. Thus 

 the late comers settle about the ends or the rear of the breeding ground. Shortly after 

 the ist of June the females of 3 years and over begin to arrive. Each is pregnant, 

 and is impelled by her condition to seek a place to give birth to her pup. The females 

 on arrival at once land and join a bull, and within a few days, sometimes a few hours, 

 they give birth. Each day other cows arrive, and the harems grow rapidly. The 

 arriving cows show a tendency to join the larger groups, and consequently there is an 

 uneven growth, some bulls securing large harems early in the season, while others near by, 

 apparently equally strong and vigorous, may still have no cows. Early in the season, 

 before the arrival of the cows, there is some display of rivalry among the bulls, and 

 late arrivals attempting to gain a place near the center of the rookery are frequently 

 subject to the joint attack of several bulls already in place. In general, however, the 

 stationed bulls spend much of this time in sleeping, and incoming ones gradually fill 

 in the unoccupied territory. As the height of the season approaches and cows come 

 in heat in large numbers, the bulls become continuously alert and active. Those at 

 the rear that have not obtained cows attempt to abduct some from the large harems, 

 and some fighting ensues. When bulls are in abundance, a certain number are unable 

 to secure harems and are known as idle bulls, though the observer finds them far from 

 idle. In 1914 there were comparatively few of this class of bulls. The number of cows 

 to a harem varies greatly, frequently being more than 50 and occasionally exceeding 

 100, while in many cases it is very small — from 2 or 3 to a dozen. The large harems 

 are clearly due more to advantage of position than to fighting prowess of the bulls 

 in charge of them. 



A few pups are born as early as June 10, but the majority between June 20 and 

 July 20. After the latter date the births decrease, but many occur during the last 10 

 days of July and a few during the first week in August. An occasional birth occurs 

 as late as August 10 or 15, and one on August 27 is recorded. Each female bears one 



