The date was Jan. 5, 1992. I had been hoping to find a snowy owl for years. I had learned that one was marauding around the entrance roads to Bangor International Airport, so I headed over. I was so excited, I held my breath for the entire drive. Since it was a 15 minute drive, I assume I passed out several times and terrorized other drivers, but I don’t recall.

There it was, sitting atop a light pole, exactly where it was supposed to be. They do that. They have their favorite perches. It stared at me in an unconcerned way, then flew off to the next pole. I immediately took a photo with my cellphone and sent an alert to friends.

Actually, no, I didn’t. This was before cellphones. This was before digital cameras. Goodness, was that only 23 years ago?

I have seen about 16 snowy owls since. Maine is in its third winter of a snowy owl invasion. Their breeding success relies heavily on the abundance of lemmings in the arctic. Three years ago, there was a boom in the population of these rodents, and owls were able to feed huge broods. In such a year, owl parents can raise up to a dozen young. In a bad year, they may not even attempt to nest.

There is not enough winter food to sustain that many owls, so most disperse southward. Numbers are still high in Maine this year, though not as high as last year. As the lemming boom ends in the arctic, the population of owls diminishes. It will be a long time before we see this kind of invasion again.

In the Bangor area, they’ve been seen around the airport. In fact, the crews have had to keep an eye on at least half a dozen so far. One or two owls have been in the Dysart’s area in Hermon and Hampden. I even received a report and photos of a reliable owl on Pushaw Road in Glenburn. A few weeks ago, I witnessed three in Biddeford Pool within a single hour. Several are on top of the mountains in Acadia. Perhaps 17 different snowy owls have been tallied in Aroostook County. Others are scattered throughout the state.

All this owl activity has encouraged me to learn a thing or two about them. One fact that is relatively obvious: in the land of the midnight sun, they are daylight hunters. It’s hard to be a night hunter when there is no night. In winter, they do hunt in darkness.

Snowy owls are circumpolar. In fact, when families in northern Canada disperse for the winter, siblings may go in all different directions, even Siberia. They are the heaviest owls in North America, though great horned owls are slightly taller. They are faster than most owls, capable of hitting 50 mph. This speed is not typically needed during their hunting forays. Like most owls, they rely on silent surprise. They spend most of their time sitting and watching, pouncing primarily on rodents, and occasionally on birds. The speed helps them defend their nests. In open tundra, many of the potential threats are swift, such as falcons, jaegers, ravens and even golden eagles.

In the arctic, snowy owls perch on rocks and hummocks above the flat landscape where they can scan for prey. In Maine, they perch on buildings and poles. I’m sure I’ll hear from people who beg to differ, but I’ve never seen one in a tree. There are few trees in the tundra, and I suspect they don’t like sitting on anything that sways in the breeze. In parts of Alaska, it is legal to hunt snowy owls for food. The typical harvest method is to place a leg hold trap on prominent perching spots.

It’s always best to keep some distance from any winter owl. Food shortages drove them here, and they don’t need the additional stress of being crowded by people. However, most snowy owls seem to feast well enough on mice and squirrels, and it’s clear that I have much more to learn about them.

On Tuesday night, February 17, Maine Audubon promises to uncover the mysteries of snowy owls. Fields Pond Audubon Center in Holden hosts Erynn Call, raptor specialist for the Maine Department of Inland Fisheries & Wildlife, and Sharon Fiedler, wildlife photographer. Bring $5 and plenty of questions to the 6:30 p.m. program.

Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. Bob developed the Maine Birding Trail, with information at mainebirdingtrail.com. Bob can be reached at duchesne@midmaine.com.