TIME BUDGETS AND ACTIVITY PATTERNS IN CALIFORNIA SEA OTTERS

To obtain time budgets for the California population of Enhydra lutris, the authors recorded 4 categories of activity (resting, feeding, "other', unknown) based on the characteristics of radio signals throughout 24 hr from individuals with implanted transmitters. Activity data based on radio signals agreed with simultaneous visual observations. Estimates of the percentage of time spent feeding based on radio signals are higher than previous estimates based on visual scan samples during daylight hours. Juvenile females fed c50% of the 24 hr day, significantly more than otters in the other age/sex classes. Adult females with pups, adult females without pups, adult males, and juvenile males fed similar amounts of time (range 35-40%). Juvenile females often fed during the day when most other otters tended to test. Juvenile females may be at a competitive disadvantage compared to the members tended to rest. Juvenile females may be at a competitive disadvantage compared to the members of other age/sex classes. Time budgets at the population level may not be good indicators of population status. -from Authors