Retired forester Jim Brown leads his crew of three on a recent Saturday morning onto the grassy stubble of a private ranch west of Missoula. As the team marches across the field, a handful of gray partridges flush and disappear into the tall grass. Song sparrows chirp from inside a shed and a juvenile bald eagle soars overhead. The team notes each sighting as part of the National Audubon Society's annual Christmas Bird Count, which sends birders into the field each December to tally species across the country.
The best sighting of the day: A flock of 200 bohemian waxwings take flight from a tree and, in perfect unison, dodge left and right, up and down, as a hungry merlin chases them through the sky.
"The waxwings are an arctic bird," says Brown. "They only come down here in winter."
Brown would know. He helped found Missoula's Five Valleys Audubon Society in 1976 and he has participated in the bird count for decades. He explains that at the turn of the 20th century, there was a holiday tradition called the Christmas "Side Hunt." Friends and neighbors would go to a field, choose sides, and try to kill as many birds as possible, no matter the size or the species. The winner was the team that had the most dead birds at the end of the day.
Frank Chapman, an Audubon official, organized the first Christmas Bird Count in 1900 to encourage people to count birds during the holiday season rather than kill them. A century later the count is perhaps the nation's longest running experiment in citizen science.
"It's fun and it's science," says Brown. "It helps us understand how things like climate change affect birds. For instance, we are seeing more flickers than we did 30 years ago in wintertime and we think they are benefiting from milder winters."
Cornell University compiles the data from each year's bird count, and develops software to track the prevalence and movement of different species across the country and the world.
In Missoula, 16 groups with a total of 76 people went into the field this year to count birds. By the end of the day, the Missoula circle, as it's known, counted 9,415 birds and 83 different species. There were 31 different bird count circles planned in Montana this winter.