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Otters in our midst – Lutra canadensis

River otters are one of 11 species of mustelid carnivores in British Columbia, the others being weasels (three species), wolverines, skunks (two species), martens, fishers, badgers, sea otters and mink.

By Karl Ricker,

Whistler Naturalists

Only the otter and mink depend upon water for locomotion, cavorting, play and food sources, although they sleep and loaf on land.

The river otter is very abundant along the coastline, found in salt, estuarine and freshwater lakes, rivers and creeks entering the ocean. The Squamish estuary is a dependable spot to seem them, and when the salmon are running they are there in spades to feast upon the spawners and their smolting progeny.

Fish is their main diet, and hence they are constantly marauding fish farms and hatcheries. Otherwise the marine dwellers will resort to crabs for a meal.

Inland, the mammologists regard otters to be rare. In fact, a noted authority, Dr. Ian McTaggart-Cowan, often visited the Whistler area from the 1930s to 1950s and apparently never saw one or heard stories of trapped specimens.

In that era there was a mink farm at Nicklaus North, which was likely the main source of the only aquatic mustelids in our waterway. It would be interesting to review old trapping records to see what was collected in Whistler’s pre-ski resort days.

Certainly the rodents (beaver and muskrat) would be the dominant trapped animals from the waterways, and both are abundant at present.

In fact in my recent sightings of otters those with me who were unaware of otters were misidentifying them as muskrats. But there are easy ways to tell them apart, even while swimming. Otters are twice the size of the half-metre long muskrat (including the tail). The muskrat’s tail (20 to 30 cm in length) is somewhat scaly and flattens from base to tip, whereas the otter’s tail is similar to a thick rope, perfectly round but tapering to its tip, reaching a length of 40 to 50 cm. The tail of the otter is exposed as a sinuous arc when the animal dives below the surface. Otherwise, while swimming on the surface, the larger head of the otter protrudes above, creating a noticeable bow wave. The muskrat’s head is below the surface with only its nose above and the generated wave is a mere ripple.

Finally, the head of the otter, with its short pinnate ears, resembles a pup seal when protruding above the surface, and hence great confusion when looking at marine mammals at the Squamish estuary – until they dive, the tail providing the identifiable clue.

River otters are divided into two or three subspecies in British Columbia. Those of the marine area, L.c. pacifica , are found on Vancouver Island and throughout the mainland coastal area, including lakes and tributaries of the lower Fraser River Valley, and as far north as Prince Rupert and beyond.

Another subspecies, L.c. evexa , is found sparingly throughout the Interior Plateau and into the Kootenays. There is also a "race" on the Queen Charlotte Islands, whose own subspecies recognition is in doubt.

To compare them, the coastal subspecies are darker and larger than those of the Interior. Ours appear to be the coastal type.

Locally, otters are regularly seen on the Birkenhead River, and the nearby Lillooet Lake-River delta area when salmon are spawning. I have seen them five at a time where the Duffey Lake Road crosses the Birkenhead. Closer to home, my first encounter was during the 2003 Christmas Bird Count. A large otter was slithering slowly on the surface of the ice at Shadow Lake, toward a nearby Canada Goose sitting in the water.

The latter kept its distance and when the otter slid into the water the goose moved to the other side of the pond. Then the otter would climb back onto the ice to again size up its quarry’s position. This cat-and-mouse game continued for 30 to 40 minutes before the goose decided to fly to another area of open water.

This summer, while conducting a bird survey for the Whistler Fisheries Stewardship Group, we saw a group of three otters cruising in Nita Lake – obviously after the stewards’ fish. More recently, during the autumn, there have been two otters methodically working the ponds on Nicklaus North Golf Course; they are eating fish while the ducks hold a definite safe distance limit from them.

Though otters are equipped with fully webbed feet, they do wander overland from pond to pond and they obviously reached the golf course by swimming in the River of Golden Dreams before going overland to the ponds.

Yes, there are now otters in our midst – is this a new phenomenon for Whistler? Let’s have some readers’ responses.

Upcoming Events:

Saturday, Nov. 6 th , Monthly Bird Walk – The next bird walk shifts to the later fall/winter time of 8 a.m. Join Whistler experts in the monthly update of our feathered locals and migrants. For details, contact Michael Thompson at 604-932-5010.

Wednesday, Nov. 10 th , 6 to 7 p.m., MY Place – Whistler Naturalists Annual General Meeting. Whistler Naturalists encourage all current members and anyone interested in getting more involved to join us for our sixth AGM. The AGM will include elections to the board; new board members welcome. For information contact Tracy Howlett at 604-935-9745.

Wednesday, Nov. 10 th , 7:30 p.m., MY Place – Bob Brett, "Whistler’s Old Trees: A Story of Fires, Floods, Pathology, and Patience". Local ecologist Brett will present his study of over 500 Whistler-area trees in which he used tree rings to determine the age of trees and forests all over the valley. Find out where to find Whistler’s oldest tree and the age of some well-known locals, like the big spruce at Meadow Park and the swinging tree at Nita Lake. There will be a social and tree ring display before and after the show. Doors open at 7 p.m. Admission at the door is $5 with a 2004 Whistler Naturalists membership or $7 for non-members (children under 12 free).