22. Pipilo maculatus

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February 27, 2017

Starting about noon, the front porch traps whatever heat the sun might offer. Today, sunshine warmed my hands as I sat on the bench, well bundled. From several days indoors unwell, this was my first foray to the garden. Along with sunrays, I absorbed small bird sounds, buzzing, quiet rasps of the Bewick’s wren in the thicket. Snowdrops have almost finished blooming in the perennial bed and yellow crocuses are up. Winter is letting go.

My symptoms last week alarmed us. Slight paralysis on one side of my face made us fear that something bad was happening in my head. I sat in the passenger seat and in medical waiting and examination rooms as Holly and Fuller cared for a dad and granddad with health issues. We found out that nothing bad is happening. My face again works perfectly well. But an event like that makes you think. This morning I resigned from the board of the neighbourhood association and from leadership roles in its committees.

You need to stop and listen to the message from a health scare, or what would be the point of it? “Face this,” it said to me. “You’re paralyzed. You have not manifested community leadership such as you imagined was in you. People around you do not open to each other’s truths. Neither do you. Battle darkens your heart with enmity and political expedience. People who trusted you deserve better from you. Before, in greenspace projects at Fern Street, Begbie Green, Emerson, Adanac, your little group heard each voice, welcomed each viewpoint, opened border checkpoints between your individual realities. Amazingly smart and effective mind emerged among you. Now factions snarl in separate cages.” Time to leave neighbourhood politics.

The sun offered surprising heat on the front porch. I had to remove a sweater and fold away my hat’s earflaps. Another bird in the thicket scuffled on the ground in oak leaves. Looking deep into shade from the sunny porch I could barely discern its orange flanks: Spotted towhee – orange sides, black back with white streaks and spots, red eye – the only towhee we see on Vancouver Island. It revived my self-esteem; my gardening in this yard provides enough overhead cover with enough leaf litter to attract a towhee to feed here.

“THE DENSE UNDERBRUSH OF GARDENS…”, announces my old copy of Birds of Victoria and Vicinity, “… is (a) favourite haunt of this colourful ground dweller.” This winter a towhee has often visited along with other sparrows in mixed feeding flocks. With spring it will soon seek better habitat for its nesting territory. I wish we could provide it here. Birds of Victoria and Vicinitysays that the nest would be close to the ground, “…well hidden in a thicket or a garden shrub that has trapped a few of last year’s fallen leaves.” We can supply dense underbrush and leaf litter here, but not a wide enough extent of it. A study in Portland showed that Spotted towhees choose breeding territories in natural areas as small as one hectare. This hillside can’t offer that much.

Anyway, it’s best that towhees don’t nest here. The cat would kill the fledglings. The black cat from next door owns this front yard for night hunting. On spring and summer mornings I find remains of juvenile birds on the lawn. Cats are a major predator for Spotted towhees in cities. Amy Shipley (2013) and her collaborators in Portland entitled their study: Residential Edges as Ecological Traps: Postfledgling Survival of a Ground-Nesting Passerine in a Forested Urban Park.They found that Spotted towhees prefer to nest along the edges of their densely-bushy breeding habitat, and that high mortality results for the young birds:

“…fledglings near edges had a far higher probability of dying. All deaths were from predation, and at least 11 of 16 predation events were attributable to Domestic Cats (Felis catus) and Western Screech-Owls (Megascops kennicottii).”

I wouldn’t begrudge a Screech-Owl its meals of fledglings from the yard, but the cat predation bothers me. Environment Canada scientist Peter Blancher’s article, Estimated Number of Birds Killed by House Cats (Felis catus) in Canada(2013), sets the number between 100 million and 350 million per year. Feral cats account for about 60% of the total, and house pets about 40%. To be fair to the black cat from next door, I also find plenty of dead juvenile rats on the lawn. And Screech-Owls, do they hunt this yard at night? It’s an appealing thought, but no. Once “fairly common” on Victoria’s bird checklist, Screech-Owl has declined to “rare”. Barred owls have replaced them. We often see a Barred owl roosting in the neighbourhood, and I suppose it works this hillside after dark.
A daytime predator bird here would be Cooper’s hawk. One patrols our block sometimes. Spotted towhee’s eye-catching colour and contrast must make it a good hawk target, but the little bird generally hides its garish Halloween plumage by feeding under cover. They are specially built for it. John Davis closely observed feeding towhees in California in the 1950s. His paper, Comparative Foraging Behavior of the Spotted and Brown Towhees (The Auk, 1957), shows that Spotted towhee has evolved its legs specifically for its life on the ground amid leaf litter and woody debris.

Hopping for locomotion takes far more energy than walking or running. Davis points out that every hop propels the bird fullyoff the ground, then uses further energy to absorb the shock of landing. He’s right; try hopping for five minutes. But the ground where Spotted towhees feed favours hopping. Davis comments that they rarely need to run for cover because they feed there most of the time. Debris and vegetation would obstruct a walking and running little bird. And hopping benefits the towhee in flinging aside surface leaves to expose the damp layer beneath.

Spotted towhee’s leg and foot muscles evolved for the hop-scratch. Davis describes the “…sharp backward thrust of both feet….(as) strong claws dig into the soil cover, which is kicked as far as three feet to the rear….” The bird shifts backward in the kick, lands and hops forward again to repeat the motion. A burst of five or six vigorous hop-scratches opens a foraging pit, a depression about 10 cm wide and perhaps 20 cm long. The bird pauses to peck at bugs and seeds exposed in the pit, then hops to a new scratching place. It may proceed steadily through its foraging area for an hour at a time, covering many metres and opening many pits.

John Davis studied the towhees at Hastings Natural History Reservation for thousands of hours over many years. I’m glad we have made space and time in our era for such meticulous observation. The eminent ornithologist Joseph Grinnell founded the Hastings Reservation in 1937. He saw an opportunity for biologists to track the long succession of farmland returning to nature. The Hastings family donated their cattle ranch, 600 hectares in the Carmel Valley, to the University of California. UC’s first biological field station, Hastings served as a model for the university’s Natural Reserve System of thirty-six stations on 55,000 hectares. John Davis became Hastings’ manger and studied there for three decades.

Today’s Spotted towhee in the front yard, where will it relocate for nesting? The literature doesn’t answer clearly.It reveals that Pipilo maculatus populations on Vancouver Island and around the Salish Sea belong to the oregonus subspecies. Our Pipilo maculatus (oregonus) is the darkest of 21 Spotted towhee races. The back of its males is blackest; its white spots and streaks most minimal. Oregonus range includes the west coast of Oregon and Washington, and BC’s south coast. Its populations appear mostly resident year-round, with some short-distance migration. Birds may move down from the mountains for the winter, or slightly south on the coast.

The fall migration data from Rocky Point Bird Observatory makes me wonder though. RPBO volunteers capture huge numbers of Spotted towhee in September. It appears to rank as one of the five most numerous songbirds migrating south from the Island to the US. The RPBO information does not fit easily with a picture of a mostly-resident bird. So I ask local birders at the online forum, BCVIBIRDS.

One of them comments that a Spotted towhee banded by his group in the fall in Nanaimo died the following spring near Portland, Oregon, more than 400 km south. The Nanaimo study also recaptured banded Spotted towhees close to the tagging location at various seasons. “So some individuals migrate, while others don’t”, he concludes. Another birder notes that banded towhees from Rocky Point Bird Observatory have died locally (Sooke, Saaninch, Victoria) as well as more distantly, across the straits in Sequim, WA and in the mainland mountains near Pemberton, BC.

Another participant in the on-line forum comments that all the towhees in his yard disappear in August, after breeding season. Towhees re-appear there in late September, so it looks like a different or re-shuffled winter population replaces the breeding population. And another Vancouver Island birder adds that some of the Spotted towhees he observes during migration and in winter display more prominent white markings than do our coastal oreganussubspecies. Pipilo maculatus races arcticus and curtatus both breed in BC’s southern interior and both show more white. Perhaps arcticus or curtatus populations migrate to and through the Island. So where will today’s Spotted towhee in the front yard relocate for nesting?

It might stay here in Bowker Valley. I can think of spots with at least a hectare of dense cover: Mount Tolmie, Cedar Hill Park, University of Victoria, maybe Summit Park. How many Spotted towhee territories does the valley support. I want to know; in fact I hereby promise myself to find out. And what fun! The task is to walk Bowker Valley’s most beautiful places on spring mornings at civil twilight, and listen.

Civil twilight – the term is new to me. John Davis’ study on Spotted towhee song, Singing behavior and the gonad cycle of the Rufous-Sided Towhee (The Condor, 1958), indicates that I can depend on the males to be singing in their territories on spring mornings during civil twilight. (“Rufous-sided” was another name for “Spotted” towhee.) Searching “civil twilight” online took me first to the site of a four-piece rock band from Cape Town, South Africa. Further search revealed that dawn unfolds in three phases, “nautical”, “astronomical” and “civil”. The period of “civil dawn” (or “civil twilight”) begins when the sun climbs to six degrees below the horizon. It ends at the moment of sunrise. Today,February 27, civil dawn occurred between 6:27 and 6:58 am. It gets earlier as spring progresses. By May 15, for example, I can expect the male towhees to be singing in the morning at 4:55.

“Singing” – the term is used loosely when applied to the Spotted towhee. It ranks among our least musical songbirds, producing loud rattling trills, loud nasal squawks and loud sharp chirps. To the winter garden it contributed lively, assertive presence. And even my inexpert ears will be able to locate the trill of males in their breeding territories. If I take time to listen closely, I might be amazed. Each male will perform his individual trill repertoire during civil twilight, his own sequence and variation of tone, volume and speed – his unique statement in his local dialect.

The sun went down today at 5:54. Civil twilight will persist until 6:25. I want to make best use of my civil twilight. What matters most to me? Before I quiet and watch nautical twilight deepen horizon colours, before I turn and watch astronomical twilight bring out stars, before dark at 7:38, what song might I sing?

 

 

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