ALWAYS IN SEASON: Collared doves spread throughout our region

At this season, with the snow so deep and the birds so few, it's not surprising that our thoughts might turn to pigeons.

Pigeons are a conspicuous part of the local landscape.

They are also part of a large, diverse and quite successful family of birds.

None illustrate this more dramatically than the pigeons we encounter in our towns and on our farmsteads. These pigeons bear the common name "rock dove" or "rock pigeon," and they occur virtually across the planet wherever any number of people live.

A similar drama appears to be unfolding with another species, the Eurasian collared dove.

Reader Bob Vaudrin of Grafton, N.D., called my attention to these birds. He recognized that they were not mourning doves. He wondered if they might be turtle doves.

That's a pretty close identification. Collared doves are closely related to turtle doves, but they are a distinct species.

Other than belonging to the very large dove family-- more than 300 species worldwide -- the mourning dove and the collared dove are not especially close.

This is apparent from two prominent field marks.

The first of these is the collar, an incomplete ring of black on the back of the neck. Mourning doves completely lack this ring.

The second is the tail. Mourning doves have pointed tails that are prominent both when the bird is at rest and when it is in flight.

Collared doves have blunter tails.

There are other differences. Collared doves are a bit bigger, though this isn't reliable for identification, and they are grayer and drabber overall than the brownish and iridescent mourning doves.

Mourning doves are abundant here. Indeed, they are a characteristic nesting species and their well-known call is an anthem of summer mornings.

Note the letter "u" in the name, however. The mourning dove is named for the sad sound it makes, not for the time it makes the call.

The mourning dove's call is rather soft and drawn out. "Cooooo. Cooooo. Cooooo."

The collared dove's call is harsher and quicker. "Koooo. Koooo. Ku."

Both might become monotonous, but to my ear, this is more true of the collared dove -- but perhaps that is a prejudice.

There's another important difference. Mourning doves are not winter-hardy. Collared doves, like rock doves, don't seem bothered by the cold.

The collared dove is not a native here, nor anywhere in North America. Instead, the species originated in South Asia. It is apparently as familiar in Indian villages as the mourning dove is here.

For reasons not completely understood, collared doves have suddenly spread throughout Asia and Europe. Less than 20 years ago, they reached the Caribbean, and in the decades since, they've spread through much of North America.

The first were seen in the Red River Valley early this century.

Now, Vaudrin considers them common.

After he first called to ask about the birds, he made a scouting tour of small towns in northeastern North Dakota, finding nine collared doves in Hoople and five in Crystal, the town were they were first recorded in the state.

Why would the collared dove suddenly explode across the planet?

Perhaps, it is exploiting ecological niches left vacant by other species. Passenger pigeons were incredibly abundant in eastern North America, but they became extinct almost a century ago. There are similar stories about pigeon species in other areas, both because pigeons as a rule as trusting, tame and tasty.

Probably habitat destruction was more important than any other factor in the demise of the passenger pigeon. It required fairly extensive areas of oak forest, and these disappeared as the pioneers pressed westward. The pigeons had to fly farther to find food, and this took time and energy away from the basic business of every species, reproduction.

This same impetus may be behind the spread of collared doves. As human populations increase and land use changes, the pigeons find new areas to forage.

Collared doves have an advantage over many other kinds of doves. They are grain-eaters. It may be that the species maintains itself in our area on spilled grain. There's no shortage of this, and so the collared dove may become a permanent fixture of local birdlife, all year around.

Mike Jacobs is editor and publisher of the Herald.