The Wonders of Wrens

Twice on the Lynn Valley trail this past month, I managed to get some pictures of Wrens singing. These tiny birds burst with song much larger than themselves and it’s always a treat to see or hear them. 

When I saw and photographed the two Wrens, I assumed them to be the same species, and even possibly the same individual bird. I had found them in the same general location on the trail, separated by about a week and in location maybe only 100 metres away from each other. After submitting the pictures to iNaturalist (a website I use extensively for my observations and identifications), they were identified as two separate species in the same Genus. The Genus was Troglodytes, an evocative title for such small birds, one that stems from their habit of nesting or foraging in hidden holes, which I suppose are like caves. My first Wren spotting was a Winter Wren (Troglodytes hiemalis).

The Winter Wren constructs its nest of twigs and moss and often hides it in one of the most incredible places: the tangled roots of fallen trees (Bull and Farrand Jr., 1994). When I encounter fallen trees, I have often been struck by the vertical clifflike nature of the mass of dirt still held fast by thick tree roots. On these miniature cliff faces, the Winter Wren hides its nest, and hides it so well that they are notoriously difficult to find. Bernd Heinrich, in his excellent book Winter World, describes the nest as “a snug little cavity with walls camouflaged with a lattice of moss and conifer twiglets” (p 61). Amazingly, only the Male Wren constructs the nest (at least in the two Wren species I’m writing about here) and he will often create more than one as part of his territory, from which the female can choose her favourite. When the female chooses one of these nests, she will add the lining of fur or feathers and the male will know that his territory has been accepted (Stokes 1979). This strategy of nest building (though not the nest location) applies to the other species I spotted on the Lynn Valley Trail: the House Wren (Troglodytes aedon).

The most conspicuous feature of Wrens (the Family Troglodytidae) in my experience is their stiff little tails and the way they flick them around often perpendicularly to their backs. According to A Guide to Bird Behavior, the tail is raised more and more to the vertical with increasing excitement or disturbance. This seems to indicate that I’ve rarely observed calm Wrens. House Wrens don’t nest among the upturned roots of fallen trees like the Winter Wrens, but instead in a natural or manmade cavity. The House Wren’s acceptance of human-made structures for nesting is the origin of their name. Besides nesting in nest boxes constructed by people for birds, House Wrens will apparently also nest in mailboxes, flowerpots, and jacket pockets that are hanging outside (Bull and Farrand Jr. 1994). I can think of few more appealing things to find in my jacket pocket than the nest of a tiny bird.

References:

Stokes, Donald W. A Guide to Bird Behavior. 1979.

Bull, John and Farrand Jr., John. National Audubon Society Field Guide to North American Birds: Eastern Region, 1994.

Heinrich, Bernd. Winter World, 2003.

For more Bird Observations, see:

-Nature Observations: Pinery, Winter 2019

-Feeding Opportunities

-Eaters of the Dead

And for more photos and natural history check out my instagram: norfolknaturalist!