THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 235 



offshore dory count. Also, the number of males, i.e., the degree of 

 sexual segregation, varies in different areas (see table 43, Segrega- 

 tion of Sexes). 



I made the field counts from Kirilof Point and vicinity from the 

 same observation stations at all seasons (table 52). Because they 

 were made in different years, they cannot be considered strictly 

 comparable but they do constitute the best material available and 

 general conclusions are based on them. 



In the summer of 1955, Kirilof Point (on the Bering Sea shore 

 of Amchitka), bounded on the east by Constantine Harbor and on 

 the west by Kirilof Bay and having a shoreline of about 5.5 km. 

 (3 nautical miles), was chosen as a study area. I soon found that 

 it was frequented primarily by females, and especially mothers 

 with young (see Segregation of Sexes). Counts in this area were 

 thus not representative of the ratio of dependent young to inde- 

 pendent animals in the Amchitka population, but were biased in 

 favor of a high ratio of dependent young to independent (includes 

 both sexes and all ages other than dependent young) animals. 



PHASES OF REPRODUCTION 



Breeding season 



Mating behavior (mated pairs, attempted copulation, or copula- 

 tion) was observed in all months except October and December. 

 Harsh winter weather reduces visibility and I have spent less time 

 in the field in the fall and winter seasons. Barabash-Nikiforov 



Table 52. — Sea otters counted along 5.5 km. of shoreline Kirilof area, at 

 Amchitka Island, Alaska 



[This area included parts of Constantine Harbor, all of Kirilof Point, and part of Kirilof Bay. 

 This locality is frequented primarily by females and young. Complete counts of Kirilof Point, 

 as well as counts from parts of the area, are included in this table] 



Season 



Number Inde- De- Percent mean 



Month and of pendent pendent dependent percent 



year counts animals young Total young young 



January 1959 



6 



37 



7 



44 



16 



February 1959... 



7 



104 



17 



121 



14 



March, 1959 and 1962... 



2 



34 



5 



39 



13 



Aprn 1959.. 



5 



197 



39 



236 



17 



May 1956 



4 



164 



42 



206 



20 



May 1959 



1 



62 



11 



73 



15 



June 1956.... 



3 



126 



23 



149 



15 



July 1956.. 



6 



258 



85 



343 



25 



August 1955 



9 



278 



59 



337 



18 



September 1955. 



12 



407 



83 



490 



17 



October 1957 



3 



132 



49 



181 



27 



November 1957 .. 



11 



315 



117 



432 



27 



} - 

 } " 



j. 22 



} 



Total... 



69 2,114 537 2,651 



