As I was driving home from work one evening, I saw an odd sight in the skies over Route 128 near Montrose, Massachusetts. An immature bald eagle was flying over the highway at an altitude of a few hundred feet, and he was being mobbed by four or five smaller birds.
It wasn't that unusual to see an eagle along that stretch of road. There are several lakes and reservoirs in the area where they can fish, many surrounded by reservation land where they can roost. I saw them two or three times a year. Most often, I saw the younger ones that had not yet developed the white head and tail that distinguishes our national bird, so there was nothing particularly odd about this one.
There's also nothing unusual about smaller birds mobbing a raptor. All hawks, eagles, and owls venture into the territories of crows, jays, grackles and other blackbirds, or mockingbirds at their peril. Maybe a quarter to a third of the times that I've seen a raptor, I've seen it being mobbed.
But there was something unusual about the birds that were mobbing this eagle. Their small heads, their plump, round bodies, their sharply pointed wings, ... This eagle was being mobbed by - pigeons!
Now, pigeons are so familiar to us urbanites that we tend to overlook them, and to underrate them. True, pigeons are not as agile as the birds more commonly seen mobbing raptors, but they are quite fast. Some scientists have even speculated that falcons developed their tremendous diving speed in an evolutionary arms race with pigeons. (Not necessarily the European rock dove, Columba livia, and its domestic and feral descendants, but members of the family Columbidae.) Few birds can outrace a pigeon in straight, level flight.
But oh, the humiliation that eagle had to endure!
I have seen pigeons mobbing a raptor on only this one occasion. And they were mobbing an eagle of all things!
Epilogue: I'm curious to know how pigeons and raptors interact in truly urban areas. It is only in recent decades that peregrine falcons, red-tailed hawks and such have begun to nest in large American cities, which for more than a century had been pigeon paradise. I haven't lived in a bona fide metropolis where hawks are known to nest. Do pigeons ever mob these downtown raptors? Send me your comments, please.