We saw some twinkling in the woods the other night.

It was a rare and welcome sight, although we used to see hundreds of them in summer just after dark.

Whatever we call them, fireflies or lightning bugs may be going away.

The twinkling insects are actually beetles – about 2,000 different species on every continent except Antarctica. 200 species are native to North America.

Scientists say that some of those species have been dwindling for years.

No single factor is to blame but the reason is no mystery. We are encroaching on their natural habitat.

Fireflies make their homes in meadows, fields and the edges of creeks and ponds.

Those areas are steadily being taken by parking lots, strip malls and new homes.

The spread of artificial lights disrupt the intricate mating behavior that gives fireflies their name.

Male fireflies flash their lights to attract mates.

They can become disoriented by security and other outside lighting.

Scientists say they have a difficult time tracking firefly populations because their adult life span is 3 weeks.

They are asking volunteers to help through websites such as Citizen Firefly Survey in Boston, which encourages residents to report changes in their neighborhood firefly populations.

Scientists see fireflies as a “canary in the coal mine.”

Their decline could signal larger problems ahead for other native life.