Storm fronts aren’t the only feature captured on weather radar this time of year. Clouds of birds heading south from Canada’s Boreal Forest are showing up too, enroute to wintering grounds in the Lower 48, Central America, the Amazon and beyond.

The migration is more spectacular in fall than in spring because the Boreal Forest is a veritable bird nursery. Each spring, about three billion birds head toward it to breed, nest and raise their young. Come fall, their numbers have swelled to five billion. Their ranks include some 97 different bird species that can be seen in Minneapolis, according to the Boreal Songbird Initiative.

The initiative calls the fall migration “on par with Nature’s most famous migrations such as wildebeests of Africa or the march of the penguins.” An average of 30 to 50 million birds per night pass south over the U.S.-Canada border before winter, it said.

How do they know that? “On many nights we can track these birds on radar,” it said. Most birds prefer to migrate at night when the atmosphere is less turbulent and they often show up on radar at about 1,640 feet.

That’s cool. But I prefer the classic approach to this spectacular autumn event: Step outside on a moonlit night, listen for the calls, and - maybe, if you’re lucky -- count them flying in front of the moon.