Serenely incubating eggs in the inner city, this bird had little in common with its shy, reclusive ancestors that nested in Europe’s forests. Early in the 19th century, probably in Germany, blackbirds began settling in cities. By the mid-20th century, they were hopping around on stoops all over Europe.The rapid evolution of animals living in cities is a hot topic in biology these days. In North America, studies have shown that urban raccoons are measurably smarter than their wild cousins, since they live in an environment where food is plentiful but danger comes in hundreds of forms. (My sons are fascinated by this news and like to imagine raccoons evolving into clever goblins living around and among us, stealing our stuff.) There are moths that have evolved to avoid street lights and plants specialized to grow in cracks in the pavement. I wonder what is happening to North American robins, which now nest almost entirely in suburbs.
Many “wild” bird species — like the peregrine falcons, red-tailed hawks and laughing gulls of New York — have set up camp in cities. But the thing about Europe’s urban blackbirds (a relative of the American robin, not to be confused with North American blackbirds, which belong to a different family) is that they are very different from their forest-dwelling relatives. They have stockier bills, sing at a higher pitch (high enough to be heard over the din of traffic), are less likely to migrate (in cities there’s food and warmth year-round), and have less nervous personalities.
For many of these differences, genes are responsible. The birds’ DNA, after 200 years or less of adaptation, has diverged from that of their rural ancestors.
And, for that matter, to us.