Through responses to this column, I’ve come to know that members of the corvid family – especially crows – are the subject of much interest and attention for many people.

Although the appearance of West Nile Virus has brought them farther into the spotlight, they have been noticed for their cunning, intelligence and mischief-making for decades. As the “Birds of North America” states, “Everybody knows crows. It is a mistake to underestimate a crow’s ability. Most people have opinions about crows that run the gamut from outright hatred to bemused admiration.”

A few people – obvious admirers – have told me they put food out for crows, as they put seed out for other birds. Recently I received an e-mail from Joanne Currier of Salisbury Cove, who had a question about a group of crows she had been feeding for more than three years.

“They used to visit our yard almost daily, year round, in groups of three to five birds. Last winter, we had two groups of four. Things were fine this year until after breeding season. …

“Suddenly, they stopped visiting our yard. I hear crows around, and they land in trees nearby, but they do not land in our yard for food…one thing I have observed, though, is that since ‘our’ crows stopped visiting our yard, I don’t see as many crows around the island either. Could something have happened to the entire crow population in our area?”

Paramount in Joanne’s mind was West Nile Virus. She had commented she hadn’t heard or read anything about it this year. I did some researching on the Web, but did not come up with anything conclusive.

I visited Audubon’s site on WNV and read what’s become common knowledge since the virus first appeared: corvids seem to be particularly susceptible to it, dying within one to two weeks of contracting it; tens of thousands of dead crows studied have been found to have died of this disease.

I then checked out the Maine Bureau of Health Web site. Its avian testing results for 2005, as of Aug. 31, listed four crows testing positive, all collected in York County. Of course, this only takes into account the birds that were found and brought in to be tested; it would be impossible to say how many might have gone undetected, if any.

I next wondered if Joanne knew, for sure, that it was indeed the same family of crows she had been observing year after year. A breeding pair with young will often be accompanied by offspring from previous years, which help their parents feed and care for the newbies. These small family groups will stay together until winter, when they join large roosts of crows that have come from many different locations. The crows in these roosts will often travel miles in search of food. It’s possible the crows that had visited Joanne’s yard in winter were strangers – transients. Short of banding the birds (which can only be done by someone who has a permit and a license), there is no way to tell for sure.

It’s also plausible the crows have found an abundant food source elsewhere, and just aren’t congregating nearby as much as they had in the past. That’s not to say that WNV couldn’t have had something to do their disappearance. But my thought is this: crows are common and fairly obvious, and Mount Desert Island is a well-known travel destination for many visitors. If a large population of crows there had died, someone, somewhere, would have noticed some dead birds.

In the absence of data so far on the presence of WNV in local crow populations, I would hazard to guess that they have either dispersed to other locations, or, possibly, are undergoing a natural population fluctuation due to other factors.

I’m not aware of any detailed studies of the crow population on Mount Desert Island, so this is only an educated guess. Thank you for that thought-provoking question, Joanne!

NEWS bird columnist Chris Corio can be reached at bdnsports@bangordailynews.net