Lieutenant John Richardson of the British Royal Navy, who was engaged in two fruitless efforts to reach the North Pole, captured a little falcon. Richardson was stationed in Fort Carlton, Saskatchewan, a fur trading post, in 1820. The bird, like many other Arctic subspecies, was lighter in colour and bigger in size than its counterparts from warmer climates. Falco columbarius richardsonII—Hawk—a Richardson’s Pigeon Hawk subspecies currently known as the Merlin.
The Merlin fled as civilization spread over the plains of North America. In the 1950s, to everyone’s amazement, Merlins were discovered nesting in Saskatoon, Saskatchewan—a city with a population of 150,000.
Today, the Arctic subspecies of the Merlin flourish on urban spruce trees across southern Saskatchewan. It has moved south from Canada to North Dakota, where it may be seen nesting in Grand Forks, Minot, Dickinson, and Fargo, as well as in South Dakota.
Merlins do not build their own nests, but rather utilise those created by other birds. Nests of crows on spruce trees bordering city roadways are perfect.
Finding American Crows in cities is a relatively new phenomena. The European prejudice towards giant blackbirds arrived in North America with the colony. Corvids maintained their distance from people, who often attempted to shoot them.
As our views toward crows and magpies softened, these birds started to take advantage of the eating possibilities provided by human settlement. Merlins arrived soon after. While crows are omnivores, Merlins are purely meat eaters that hunt their prey (other birds).
In Saskatchewan, the most prevalent urban food for Merlins is house sparrows and waxwings. The House Sparrow is an immigrant from Europe. Other tiny birds, such as native waxwings, are drawn to cities by decorative tree berries grown near city dwellings.
Merlin lays four eggs on average every year. If all of the eggs hatch, it is predicted that five House sparrows would be required each day to feed the hatchlings until they reach adulthood.
However, life is not simple for Merlin chicks. If a child survives to their first birthday, it has been a wonderful year. In their first year, 85% of birds of prey perish. As a result, it is doubtful that one in a hundred will live to be 10.
Another of man’s efforts in the avian realm has resulted in House Sparrows being one of the mainstays of the revived Merlin’s diet. The House Sparrow is not indigenous to North America. In 1850, eight pairs were introduced to help reduce cankerworms in Brooklyn. These birds did not survive, but subsequent imports were significantly more successful.
The House Sparrow has evolved into a species that many bird watchers and ornithologists despise. It has expanded over much of Canada and the United States, including subarctic Canada, where there is human habitation. It arrived on the Great Plains before 1920.
The House Sparrow has replaced native cavity nesting birds such as the Tree and Cliff Swallows and is thought to be a key contributor in the Cliff Swallow’s decline. The House Sparrow is an intelligent bird that observes the feeding habits of other birds and uses this information to create new food chances for itself. It has been recorded following American Robins about to take advantage of the robin’s auditory talents in identifying worms, which it subsequently snatches. Similarly, some House Sparrows have learned to shake seeds free from feeders that their beaks cannot reach. Observing narrower-beaked birds like the Goldfinch and Pine Siskin taught me this skill.
My own observations of Christmas Bird Counts in Saskatchewan from 1942 to 1994 revealed an eight-year cycle in House Sparrow concentrations.
While suburban areas may be expanding, the vegetation inside them stays mostly unchanged from year to year. Cities are not natural habitats. We can water our plants even when there isn’t much rain. Food supplies for urban birds, on the other hand, are virtually consistent. Urban birds are protected from the natural world’s ups and downs, which are mainly caused by weather variations that impact plant development.
House Sparrow population changes do not mirror naturally occurring occurrences, but rather reach a point where human surroundings can no longer sustain them. House Sparrow numbers plummeted at that period. There is a lesson here that I hope we as humans never have to learn as we convert more and more of the earth into humanscapes. The world can only handle so many people and their pollution.
On my first voyage from the prairies to the Pacific West Coast over the Great Divide, I couldn’t help but note the lack of House Sparrows. I didn’t observe them swarming in factious masses anywhere in the urban jungles abutting the Pacific Ocean. It was a wonderful surprise to see one or two of them—the female’s delicate colouring, the black bib balancing the grey breast tones of the male, and the male’s distinctly reddish-brown wings.
On the metropolitan West Coast, it seems that House Sparrows must fight for living space with the native House Finch, a bird that is somewhat smaller than the House Sparrow but can hold its own.
If it hadn’t been for the American Fish and Wildlife Service’s vigilance, the House Finch may still be a West Coast bird. California cage-bird vendors sent “Hollywood finches” to New York City in 1940. The infringement was discovered by federal officials, who swooped down on the offenders of the International Migratory Bird Treaty Act. In an effort to avoid prosecution, the bird merchants unlocked the bird cages and let the evidence go.
In the late 1980s, an avid Saskatchewan-based birder discovered and saw a nesting pair of House Finches raise a successful brood a few homes away from his own. The House Finch has expanded on its own from the Atlantic Coast to the interior of the continent. The bird’s development has been rapid. In Saskatchewan, the House Finch population has increased by thousands in less than fifteen years, dating back to the earliest nesting record.
While the twentieth century saw the House Sparrow expand over the plains of North America, the twenty-first century may see a fall. The Merlin’s preferred prey species is the House Sparrow, which competes with the House Finch for urban nooks and crannies.
While the Merlin will eat everything it can get its hands on, the House Sparrow’s regular behaviour pattern makes it a more difficult target than House Finches.
House Sparrows congregate in mobs on open surfaces such as sidewalks and parking lots. Overhead watchers can see them clearly, and if they are birds of prey, they can generally start their assaults with the wind in their faces—the perfect flying path for a controlled swoop.
House Finches do not gather in great numbers. During the mating season, they remain in couples and go out from protected areas as required. They are never easy prey for savvy Merlins.
While Merlins are a persistent danger to House Sparrow numbers, it is widely agreed that House Finches offer a considerably bigger threat to House Sparrow populations since the two species fight for breeding sites.
House sparrows are more likely to be territorial than House Finches. They will never leave their preferred breeding region. Many House Finches, on the other hand, migrate southward from cooler places in autumn. While some scientists are hesitant to call this migration, the effect of this exodus allows House Finches that migrate south in the autumn to survive the winter months and return north the following spring.
However, once a male House Sparrow establishes its territory, it remains all year. Many people get stranded in blizzards or go hungry in areas where there is no food production during the winter months.
Merlins, like House Finches, migrate from one season to the next. Merlins with Saskatchewan bands have been discovered in Texas.
Because some Merlins and House Finches depart inclement areas over the winter, the total population of House Finches and Merlins is likely to be larger than that of the House Sparrow the following spring. Given the competition from House Finches for nesting sites and summer food, the surviving House Sparrows are likely to face increased competitive pressure.
The danger posed by the Merlin is distinct. The abundance of prey species has an impact on merlin populations, not the other way around. That is, as the number of prey species decreases, so will the number of predators, and this will continue until the number of prey species increases. The attraction of urban environments to the birds that the Merlin preys on, as well as their capacity to flourish inside and around city bounds, will ultimately determine the quantity of Merlins in cityscapes.
An urban environment is a dynamic setting where the drama of natural battles unfolds.
The arrival of the House Sparrow in North America in the 1800s altered the natural equilibrium. The corvid has gained a footing in our cities as a result of urban treeing and a shift in our attitude toward crows and their friends in the twentieth century. Songbirds are drawn to our yards by ornamental trees. This, in turn, has allowed little falcons to locate a home inside cities. Human interference has introduced big falcons, known as Peregrines, to city streets. They build their nests and perch on skyscrapers and communication towers.
Closer to the ground, Red-tailed and Swainson’s Hawks may be spotted. Long-eared Owls are shy creatures that live in thick shrubbery in suburban parks. Cooper’s Hawks guard artificial parks and flatlands. The city has become an oasis amid the agricultural desert of monoculture.
While humans have taken away much more habitat from birds than we have created for them, we may enjoy, learn, and assist nature’s species thrive without leaving the city. The way we design our parks, roadways, golf courses, and backyards is important to the survival of many species. This is a tendency that will continue as more birds learn to coexist with humans in our cities.
Martin Bailey writes a weekly nature column for the Weyburn, Saskatchewan newspaper. He has been involved in birding, banding birds of prey, and censusing endangered species for many years. He can be reached at [email protected].