The 28 square miles of the Corte Madera Creek Watershed supports a large variety of aquatic and terrestrial animals, in addition to the renowned—but much reduced— salmonid populations of our creek. The following is a brief snapshot into the lives of one of our wild neighbors, whose family has been here for many generations, along with, and before ours.

They are the playful and elusive northern river otters, feeding on the fish of the creek. The presence of otters offers a sense of the influence of the wild areas, primarily along the ridges of the valley, which contribute to the healthy watershed so vital to a healthy creek.

Walking slowly upstream in waders, conducting a survey for spawning salmon in a nearby watershed, suddenly we felt a quick underwater bump and brush along our waders. We turned just in time to see the tell-tale sleek brown body of the river otter dive back under the water. There was a local family of otters nearby, and they were just thrilled to have the easily obtained feast that the salmon that have completed spawning provide, and right at the start of the winter months.

Otters are very playful animals, a trait rare in adult wild animals. This species wrestles even as adults, and have been known to make slides down slick river banks and treat themselves to this homemade amusement park. Sliding is also used as an efficient means of travel across grassy slopes or ice. Other forms of play include chasing their tails, playing with captured prey. An otter in San Anselmo Creek was seen rolling energetically in moss before returning to the water and playing with a plastic plant pot.

Their young, called “kits”, are born between February and April. They start playing by the time they are about five weeks old. Although they wean at about 12 weeks, they stay with their mother, and she provides them solid food for almost a year. They are a very social species, and the basic social group is the mother and her young of that year. These basic family groups sometimes include “helpers” consisting of unrelated adults, yearlings, or juveniles. This extended social time provides precious opportunities to see the mother and her youngsters playing along the creek, possibly enjoying the salmonids and crayfish!
 


Comments

Jules Evens
04/08/2012 2:32pm

On April 7, 2012, we were conducting a protocol-level survey at Southhampton Marsh, Benicia State Recreation Area, Solano Co., to confirm that California Clapper Rails, an endangered marsh bird, were not present and nesting this year. (They were present in 2011 after being absent for a decade.) Although I have been conducting surveys there for several years, I had not encountered otters prior to this visit. At first we noticed otter tracks all through the upper sloughs, then saw three full sized otters actively foraging and frolicking in the main channel. Apparently other Park personnel have seen them recently, but it's unclear how long they've been there. Although I know they are fairly common in Suisun marshes, I see them much less frequently in San Pablo Bay or Carquinez Strait. Coincidentally, no Clapper Rails are present in Southampton this year. I'm wonder if they might depredate rail nests, chicks, or adults . . . I have seen otter predation on adult waterbirds (scoter, pelican) and wouldn't be surprised if their appetite was pretty eclectic.

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