November 1, 2016
Another little bird has a new name. The American Ornithologists’ Union replaced “Winter wren” along the Pacific coast in 2010. I noticed the change only today. First I resented it, but now I’m glad. Researchers at the University of British Columbia established our west coast bird as a separate species, Pacific wren, Troglodytes pacificus, a cryptospecies. “Crypto-“ means “concealed”. David Toews and Darren Irwin discovered a new bird, four million years old, hiding in plain sight. It appeared briefly in plain sight in this back yard this afternoon. A very small brown bird with a very stubby tail cocked up over its back probed for insects in the bark of the ornamental plum tree in dim November.
About 4:00 pm, sitting on the fire escape, I was hearing the deep river of homebound traffic from Fort Street beyond the condo blocks. A sound more immediate around me was rain on leaves. A few still hung on the Horse-chestnut tree, but most cast a soggy, tawny mat over the lawn and garden. Neighbourhood and family concerns have delayed my leaf raking and shredding.
I noticed motion low inside the thicket. Little birds shook thimbleberry stems. Glimpses of black hoods and white tail feathers disclosed juncos. A wren appeared on the plum trunk then disappeared down into the bushes. I got only one clear look, but it matched with the illustration in Peterson’s Field Guide to Western Birds (1990). The citation read: “Winter Wren (Troglodytes troglodytes)” Consulting Birds of Victoria and Vicinity (1989), I found Winter wren listed as resident here, common year-round. The book advised:
“In winter, look and listen for it low down in thick, moist, damp woodlands of the city, but watch for it also in the garden if you have an overgrown corner with thick vegetation.”
Yes we do have such an overgrown corner – and I’m proud of it today for attracting a bird that demands deep cover.
I might be less proud if the Horse-chestnut leaves kill the lawn grass before I get around to shredding them. Emma, my companion in leaf raking, had some seizures last week. They were minor and brief but they rule out yard work at present for her. We look for exercise on less bumpy ground. Yet my biggest worry is not Emma or the leaves. This week the Greenspace Committee will host a North Jubilee Neighbourhood public meeting about parks. We hope to make something happen. Opposition may arise and I am sweating it.
Victoria is renewing the city’s Parks Master Plan. It will guide park development for the next twenty-five years. My friends and I want the long-term plan to include a park that will daylight Bowker Creek, free it someday from culvert, to meander across a corner of our neighbourhood. Political contention disturbs me. My determination disturbs the Neighbourhood Association board. Today on the fire escape my time of listening stillness brought not peace but a sense of the back yard as vibrant nigh to bursting, no more tranquil than the song of “Winter Wren” in John Neville’s Bird Songs of Canada’s West Coast album (1999).
Compared to other little birds on the album, Winter wren sounds fraught. Notes stampede, full-tilt in fancy vocal tricks without melody. I don’t remember hearing it in the wild, yet I must have. Surely, many of those little birds sang in Haida Gwaii in spring some decades ago as I walked transects across a valley in ancient rainforest. I definitely sang. The Black bears of those islands are the world’s largest. I bellowed, tromped and whacked trees with a stick, hoping that bears would decide they didn’t want to meet me. Perhaps my racket put the wrens off their song.
I saw them. In fact Winter wren is the only bird I associate with those memorable walks deep in old-growth forest – almost the only animation. The place was too still for me, too quiet and dark – immense green gloom, taut with suspense. No sunlight penetrated the tree canopy. No breeze or weather. Moss blobs, shaped too much like bears, soaked-up all the noise I could make. Any time a tiny wren darted, perched, cocked up its tiny tail and scolded, I welcomed the event.
My task of walking across the valley had the purpose of evaluating trout and salmon habitat. A mining company wanted to excavate, and regulations required environmental assessment. A biological field technician, I stopped at each creek, recorded habitat information on data sheets and set minnow traps. Baiting each trap with a sticky glob of salmon roe left my hands aromatic with the favourite food of Black bears. As thoroughly as I tried to rinse my hands and seal and rinse the bait bag, I knew I still smelled edible to bears. But they did avoid me.
Those good old memories felt threatened today. I searched “Winter wren” on the internet and found the name replaced by “Pacific wren” for the BC coast. The grumpy-old-man lobe of my brain resented the change. I had known Winter wren, Troglodytes troglodytes, as holarctic. It had spanned the boreal of Europe, Asia and North America. My Celtic ancestors celebrated Wren at winter solstice as symbolic king of the old year.
Like the old king of the year past, my grumpy-old-man response needed killing and burying by new information from Dave Toews and Darren Irwin. I searched out their article, Cryptic speciation in a Holarctic passerine revealed by genetic and bioacoustic analysis (in Molecular Ecology, 2008). It supplied vital evidence that our Pacific coastal birds are a separate species, even though they look and behave so much like eastern Winter wrens. Toews and Irwin found a zone in northeastern BC, around Tumbler Ridge, where breeding ranges of western and eastern birds overlap. The study showed both occupying the same habitat, in which eastern and western males staked out neighbouring territories. Western males and females paired up; eastern males and females paired up; no mixing.
DNA analysis confirmed that ancestors of the eastern and western birds had parted ways more than four million years ago. The American Ornithologist’s Union responded by officially separating Winter wren into three species: Eurasian wren, Troglodytes troglodytes; Winter wren, T. hiemalis, of eastern and central North America; and our Pacific wren, T. pacificus.
So similar, why don’t Pacific and Winter wren interbred? The Toews and Irwin study suggests that song sorts out the species. The female finds her little, camouflaged mate by his song. Troglodytes pacificus sings in a generally higher frequency range than T. hiemalis, and changes his note more times per second. Even I can easily hear the difference. To my ear Winter wren sounds more melodious, rich, attractive, but my preference hardly matters.
Toews and Irwin also authored the Pacific Wren article at Cornell University’s Birds of North America website. Exploring it and other sources, I learn that deep rainforest, such as I walked in Haida Gwaii, is prime habitat for Pacific wren. For nesting they prefer old-growth, greater in age than 200 years. They favour intact forest blocks larger than twenty hectares (fifty acres), and prefer to nest deep within it, at least 100 metres from its edge. Dead, decaying and fallen trees of old forest provide a prime source of their insect food, and they often nest in woodpecker holes in rotting snags. They nest most abundantly along the many small streams that drain rainforest valleys, and frequently conceal their nests in rootballs of trees that fall in the wet ground of the riparian corridor. Where the trees fall, patches of bright daylight sprout dense undergrowth where the wrens find food. Pacific wren nests also beneath overhanging bank of the streams.
Research suggests that the web of life in rainforest valleys connects Pacific wren, salmon and bears. Mature salmon from the ocean ascend the streams in autumn to spawn and die. Bears feast on the salmon then fertilize the forest soil with their droppings and with fish carcasses they carry from the stream. The nutrients enrich the riparian (streamside) ecosystem, including its insect populations, which feed wrens. Nutrients quickly leach from rainforest soils, so the ecosystem needs its yearly salmon fertilizer.
Gardeners here in Bowker Valley recognize the same need for yearly fertilizing. Our climate is dryer than classic Pacific wren breeding habitat, but heavy rain in winter washes nourishment from our soil. Riparian forest ecosystem functioned for thousands of years along Bowker Creek. Pacific wren males sang in spring in old-growth habitat. Now none of it stands along the stream. Vancouver Island has lost about 90% of its ancient forest. Pacific wren populations appear to be decreasing. It fits a worldwide pattern. Varied reports indicate that about 40% of Earth’s bird species are in decline, with 8% already nearing extinction. The main cause is habitat destruction by humans. The planet has lost half its wildlife population since my class left high school, including 75% of animal life in freshwater ecosystems. Bowker Creek and Pacific wren are only snapshots from the big picture. Would Earth be better without humans, I wonder.
Troglodytes pacificus, fortunately, is fairly versatile in its habitat choice. North Jubilee neighbourhood thickets can provide cover and insects in the cold months, and our suet feeders contribute extra energy. Pacific wrens move to and through the city as winter pushes them down from the mountains and coastward from the BC interior. The bird in the back yard today could be a Victoria area resident or a short- or long-distance migrant. Rocky Point Bird Observatory (RPBO) at the southern tip of the Island sees hundreds during fall migration, with highest numbers passing south in mid-October.
The RPBO website links to a report on Pacific wren behaviour that I found disturbing. Ann Nightingale and Ron Melcer Jr. authored the article in Western Birds (2013), Conspecific Nest Aggesssion of the Pacific Wren on Vancouver Island, British Columbia. It provides a horrifying record of a prolonged attack by a Pacific wren female on the nest of another female. It made me think about who these little creatures are and who we are.
The nest was in a carport. Habitat was semi-rural and adjacent to a wooded corridor along a stream. The attacker was attempting to drag nestlings out and take over the nest. Both females may have been mates of the same male. Recent heavy rains, the authors conjecture, may have destroyed one female’s nest, leaving her in need of a drier site within her male’s territory. The account distressed me, perhaps because it could have been a human story. Polygyny, in which a male mates with more than one female, and infanticide among jealous, competing mothers occurs in humans. Polygyny probably served our species well for tens of thousands of years. Some evolutionary anthropologists assert that we began our shift to monogamy only a thousand years ago. Our economies and communities were expanding. Village-based culture was collapsing. Monogamy and the nuclear family provided better care and protection to infants in a more complex civilization. We have built monogamy into our morality. Today it offended me that Pacific wren doesn’t observe the social code in which we humans invest so much effort.
Ridiculous, but it points to the new capacity that Earth labours to develop through the human. Pacific wren behaviour is more strictly bound to genetic coding. Humans can use concepts to evolve personal behaviour and to unify civilizations. I am offering my personal answer to the question: Would Earth be better without humans? The planet tends not to throw away new capacities, but to fit them in. By the human, Earth now learns to see itself as a whole, to know itself and its universe. It’s not about us, just the capacity we carry. The concept of justice for all life evolves in us now.