Something is killing birds in unusually large numbers.

An as-of-yet undetermined disease has taken a heavy toll on birds such as robins, blue jays and grackles in about a dozen Mid-Atlantic and Midwest states. The die-off started in May and, while it hasn’t reached New England yet (as far as we know), officials at conservation organizations are encouraging people to take precautions to protect birds. Among the precautions: Stop feeding birds (or at least wash all feeders with a 10 percent bleach solution) and discontinue the use of birdbaths temporarily.

Disorientation, imbalance, lethargy and encrusted or cloudy eyes are among the symptoms of the birds afflicted with the disease. Young birds appear to have been disproportionately impacted. Researchers have confirmed that this differs from the avian conjunctivitis that has plagued house finches and goldfinches for many years. They have also ruled out many other potential causes, such as bacteria, viruses and parasites that commonly afflict birds.

It’s important to know what is not causing the die-off, of course, but finding out what is causing the event is even more significant. Determining that is still a work in progress.

One theory, which has been applauded by some and discounted by others, is that the die-off is related to the 17-year Brood X periodical cicada emergence. The geography of the die-off and emergence appears to align, and the theory suggests that the cicadas, which have been underground for 17 years, have soaked up pesticides, herbicides and whatever other nasty stuff we’ve been using to control insects and grow our grass and crops. It seems to make sense, but as I’ve mentioned, many researchers do not think the link is plausible.

There is also evidence that the outbreak may be subsiding, which would be the best-case scenario. It is important, of course, to continue to research the cause of the die-off to prevent it from happening again.

As of this writing, New England has not been impacted by this mysterious disease — as far as we can tell anyway. Some of the birds have been found close to our region, however, in states such as Pennsylvania and Virginia, so it is certainly not out of the question to think it could get here.

As a precaution, New England conservation organizations are encouraging people temporarily to halt feeding birds and offering water in birdbaths until the situation is under control and, hopefully, the cause is found. The birds will be just fine without food from feeders, especially this time of year when natural food sources are abundant.

If you do find a dead bird showing any of the symptoms mentioned earlier or find multiple dead birds in one area, contact the N.H. Fish and Game Department’s wildlife division at 271-2461.

I’ve mentioned in previous columns that I don’t like when birds are in the news because it’s usually bad news if the media report on bird happenings. This is certainly the case here, and I’m hopeful that the reports of the event subsiding are true. We’ll continue to follow the story.