Cold of Winter Leavened By The Joy of Watching Graceful Merlins in Flight By JOE EATON Special to the Planet
Winter, I have to admit, is not my favorite time of year: The cold and the dark have no appeal for me. (I may have been an emperor penguin in a past life). I begin to get seasonally affected around Halloween and it doesn’t really let up until Groundhog Day. But there are compensations. The waterfowl are back in force, and the winter complement of songbirds are here. And along with them come the merlins. If winter has a single redeeming feature, it’s the opportunity to watch a merlin at work, dogging a flock of shorebirds at the edge of the bay.
It would be nice if there was some kind of association between the falcon and the wizard, but it seems unlikely. Ernest Choate’s Dictionary of North American Bird Names derives “merlin” from the Old English marlion, the falconer’s term for the female of the species. In the hierarchy of falconry, the merlin was the lady’s bird.
Catherine the Great flew merlins, as did Mary Queen of Scots who at one point in her difficulties with Elizabeth I was in the custody of the royal falconer, Sir Ralph Sadler. Sadler allowed Mary out of her confinement for short hawking excursions. Trained merlins specialized in hunting larks; the quarry’s tendency to evade predators by flying straight up made for interesting contests.
These small, dark falcons have a distinctive flight profile and hunting style. In their classic Hawks in Flight, Pete Dunne, David Sibley, and Clay Sutton comment that a merlin is to a kestrel what a Harley-Davidson is to a scooter. A merlin’s flight is strong and direct, with short, powerful wing strokes. They can be sneaky on the approach, hugging the treeline; at eastern hawkwatch sites, the typical response is “There went a merlin.” On the attack, they may fly low over the ground, tailchasing an individual target and climbing above it for the final stoop.
At rest, merlins can be distinguished from kestrels by their more compact proportions and weaker facial pattern; the falcon mustache is present, but pencil-thin. They can also be mistaken for juvenile sharp-shinned hawks, with which young merlins sometimes associate during migrations; merlins have the characteristic falcon pointed-wing silhouette and narrower banding on the tail.
Some years ago, there was a mockingbird in my South Berkeley neighborhood that had learned to imitate the sound a telephone makes when left off the hook. After enduring this for a couple of months, I came home one afternoon to find a merlin atop a tall conifer next door, methodically plucking something as falcons do—something resembling a mockingbird. And I never heard the phone-off-the-hook noise again.
Although they’ll take other avian prey, including horned larks, pipits, and flickers, most of the merlins that winter in California are shorebird hunters. To a merlin, a mudflat between tides is a smorgasbord. Thirty years ago, Point Reyes Bird Observatory biologists Gary Page and D. F. Whitacre kept tabs on a female merlin at Bolinas Lagoon for an entire winter season. They estimated that she caught 264 sandpipers, along with a smattering of warblers, sparrows, and blackbirds, with a success rate of 12.8 percent on 343 observed hunts. Apart from birds, merlins hawk for large insects like butterflies and dragonflies, and catch the occasional small mammal.
Most of the merlins we see around here are of the subspecies columbarius, or what Sibley calls the taiga form. (Sibley has an aversion to Latin, for some reason). It’s the middle-of-the-road merlin; there’s also the darker subspecies suckleyi, Sibley’s Pacific (black) merlin, which I’ve spotted a couple of times, and the rarer pale richardsoni, the prairie merlin. Richardsoni, as the common name suggests, breeds in the northern prairies, and has become a city bird in places like Edmonton and Saskatoon. Suckleyi comes from the wet coastal forests of mainland British Columbia and Vancouver Island. But columbarius is, in fact, a bird of the taiga, the great boreal forest of North America; other forms inhabit the same zone from Siberia west to northern Europe.
Taiga merlins tend to avoid the deep woods, hunting and nesting in edge environments: near treeline or alpine timberline, or around lakes, bogs, and regrowing burns. Where available, they’ll take over the old nests of crows and magpies, although tree cavities are sometimes used. After a brief aerobatic courtship, a merlin pair starts its family late in the northern spring, timed to take advantage of the annual crop of fledgling songbirds (which in turn depend on the spring flush of foliage-eating insects).
It hasn’t received nearly as much press as the tropical rainforest, but the taiga is crucial habitat for North American birds. Over 300 species—ducks and gulls as well as raptors and songbirds—nest there, and 96, including the merlin, have more than half their breeding population in the boreal forest region. It’s an ecosystem under intense pressure. Canada, which contains most of the North American taiga, fells 2.5 million acres of forest per year, mostly in clearcuts. Forestry companies own almost a third of the Canadian taiga, and oil and gas interests are also active; only 6 per cent has any form of protection. And the whole boreal community—trees, insects, birds—is vulnerable to the effects of climate change.
The loss of taiga habitat may already be affecting bird populations. Data from Audubon Society Christmas Bird Counts shows alarming declines in several boreal-nesting species, including the once-abundant rusty blackbird. The one taiga breeder that bucks the trend is the merlin. Although their numbers plunged during the DDT years, the small falcons have made a dramatic comeback; Count numbers from 1965 through 2002 document an increase of 3.3 per cent per year. Credit their adaptability, and probably a large measure of luck. Let’s hope it holds.
Photograph by Mike Yip
Merlins have the characteristic falcon pointed-wing silhouette and narrower banding on the tail.
These small, dark falcons also have a distinctive flight profile and hunting style.