Posted by: Anne Murray | November 6, 2009

Owls on the bay

It’s the time of year I get excited about seeing owls so I took a stroll along the dyke at 72nd Street, one of the locations where fancy new signage for the Metro Vancouver Regional Park has recently been installed. It was 4 pm, with daylight fading and the tide high, and sure enough a Short-eared Owl was patrolling the old field grassland outside the dyke, on the lookout for tasty Townsend’s voles. It was almost immediately intercepted by a female Northern Harrier and a slight change of route was taken by the owl. These two species use the same habitat, eat the same voles and often interact. Harriers seem to be holding their own around Boundary Bay, while Short-eared Owls numbers appear to have trended downward (they used to nest in the Centennial Park area, for example, and naturalists used to regularly report flocks of 50 or more roosting birds near the dyke). It is difficult to know why this would be , but competition on a diminishing habitat might be a reason. Historically, much of the delta was marshes, rough grassland and small scattered shrubs, a kind of wet prairie. Dyking in the 1800s changed that, with the floodplain steadily converted to rich agricultural ground. Fallow fields continued to provide habitat for owls and harriers, which also utilized the uncultivated marshland, or “saltings”,  outside the dykes. In recent years, more and more delta farmland has been converted to intensive farming , residential or industrial use, with a consequent decline in fallow and old fields. The work of the Delta Farmland and Wildlife Trust has been critical in maintaining this type of habitat, in set-a-sides and crop rotation programs, otherwise we would have lost more species than we have.

Thinking of other owls, a Snowy Owl has been seen at Iona, so maybe we will have a snowy year, although it is only a few years since the last big invasion. That would entice a lot of birders to Boundary Bay, one of the best locations in the Lower Mainland for seeing and photographing these beautiful large owls in an invasion year.

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Responses

  1. Hi Anne,
    Nice post – got me reminiscing about birding walks on the dyke looking for short-eared owls over the flats and long-eared owls in the scrub along the ditch. Miss being able to jump in the car for a quick raptor/owl fix!


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