But now comes a surprise. When students went to downtown Seattle to count bird species, within the first 10 to 15 minutes they spotted pigeons, finches, sparrows, crows and an occasional hummingbird.
Their count was 10 to 15 different kinds of birds — not many, but they expected that.
When they went the other way (to the far edge of the metropolitan area near the Cascade Mountains, where there is mostly forest, protected parks, reservoirs, and humans are sparse), in the first 10 to 15 minutes, they found a very different set of birds (woodpeckers, wrens, warblers, chickadees).
In all, 20 different species — more, but not many more than downtown.
Then they went to the in-between zone, the Seattle suburbs, where they expected an in-between count, something like 12 different kinds of birds. But that’s not what happened.
Birds in the suburbs.
“We were astonished,”
Marzluff writes. The suburban count (again in the first 10 minutes) was “30 or more species,” says Marzluff, some from downtown, some from the mountains, but also spectacularly new samples of “violet-green swallows, willow flycatchers, killdeer, orange crowned warblers, American goldfinches, and Bewick’s wrens … [plus a few] white crowned sparrows.”
The suburbs produced, by far, the most biologically diverse collection of birds.
What? This region that’s all sprawl, a hodgepodge of strip malls, yards, highways, parking lots, hedges, fences, is “a mecca for birds”? More than a forest? No way, thought Marzluff. So he counted again. Then again.
And after checking and compiling “more than 100 locations in and around Seattle,” he writes, he and his team discovered “a consistent, but unexpected relationship between the intensity of development and bird diversity.”
To his great surprise, Marzluff concluded that the “greatest diversity was not in the most forested setting. Instead, bird diversity rose quickly from the city center to the suburbs and then dropped again in the extensive forest that eases Seattle into the high Cascades.”
If you plotted it on a graph, bird biodiversity looks like this …
This majestic creature is a Victoria Crowned Pigeon (Goura victoria), a large, bluish-grey bird native to New Guinea. The bird is named in honor of the British monarch Queen Victoria.
The elegant crest of feathers on its head also forms the pigeon’s “crown.”
In addition to its bluish hue, the Victoria Crowned Pigeon has several features that distinguish it from the pigeons that roam around New York City: It has a distinctive, maroon breast, a crest of feathers with white tips, and bright red irises.
The Victoria Crowned Pigeon is the largest of all living pigeons, and can even stand as tall as a turkey. Photo: Wikipedia
Battle of the birds (Graphic: Ryan F. Mandelbaum; Raven: Wikimedia user CanadianWikilover; Crow: Wikimedia user Mdf; Sky: Wikimedia user Mohammed Tawsif Salam, Screenshot via Nintendo, Wikimedia Commons)
Crows and ravens are hard to tell apart, but basically, the common raven is bigger than the American and Northwestern crow.
So you might think that ravens would win in a fight. But that doesn’t seem to be the case.
One thing you might not know about bird nerds is that many of us are citizen scientists, logging all of the birds we see, along with our observations, into an online database called eBird.
It’s a worthwhile endeavour that can lead to new scientific insights about birds.
A pair of scientists analysed 2000 eBird logs and learned about this strange corvid behaviour.
“Both crows and ravens are insanely smart species, but our cities and agricultural areas are hugely dominated by crows, while ravens live in more wild areas,” study author Benjamin Freeman, postdoctoral researcher at the University of British Columbia, told Gizmodo.
“Crows’ social behaviour helps them keep their domination in cities and agricultural areas.”Basically, the raven, being a big cousin of the crow, would probably win in a one-on-one fight, but such events rarely happen in the wild, said Freeman.
Instead, crows band into small groups to chase and attack ravens — 97 per cent of the time, the crows are the aggressors, according to the paper published in The Auk Ornithological Advances.
These attacks occur more frequently during crow’s nesting season or during winter, implying that the crows could be preemptively fending off larger potential predators or fighting for resources like food.