In education circles these days, there is much discussion about the Common Core. To a naturalist with an interest in birds, the common core means something very different.
Take a walk in the forest on a chilly winter day, and you will probably see and hear little. The summer birds are long gone; riotous song will have to wait until April.
But if you are patient and keep a sharp ear out, you may hear a few very high-pitched call notes. Sometimes they are so faint you wonder if you are really hearing anything. If at an earlier time in life you listened to a little too much music ramped up to wall-shaking loud, you may be right. However, if your hearing is still acute, follow up on these minute sounds. The trail will lead you to where the action is, what little there is in the forest this time of year. Odds are you are hearing the soft call notes of either chickadees or golden-crowned kinglets. Among the Douglas-fir, the chickadee will be the chestnut-backed chickadee. Higher up it will be the mountain chickadee.
The calls are soft, just loud enough to be heard by other members of the group as they scour the forest for the few insects, spiders, cocoons and eggs to be found. High-frequency calls travel a very short distance before the forest absorbs the sounds, more quickly than low frequencies. It’s not good to be too obvious when you are part of a rather limited predator menu this time of year.
There is safety in numbers. Chickadees and kinglets travel together in troops ranging in size from four to 40. With so many eyes, a sharp-shinned hawk is less likely to fall among the flock undetected.
Take a little time, and you are likely to find more than just chickadees or kinglets. A couple of red-breasted nuthatches will usually be in the mix, along with one or two brown creepers. The party is growing, and the chickadees and kinglets are just the “common core.” More eyes, greater safety.
Keep watching. A hairy woodpecker may announce itself with quiet drumming as it peels a bit of bark away to reveal lunch. The nearly silent and frequently overlooked Hutton’s vireo will also join along. On rare occasions you might even find a colorful Townsend’s warbler. It’s getting to be a real party.
Others will join in for a dance or two, but only briefly. Spotted towhees and Pacific wrens will come out of hiding and forage more actively when the common core passes through, only to return to the deep shadows when it moves on.
Some forest birds are more aloof. Robins and varied thrushes march to the beat of their own drummer, concerned more about finding the next madrone heavy with fruit. Pine siskins, too, keep their own company. But they are more interested in seeds than a chilled spider.
Not all family groups of birds attract roadies in winter. Bushtits scour hedgerows and understory much like the kinglets, but you will rarely see tag-alongs with this group. I’m not sure why the difference.
Forest birding in winter is challenging, but it can be fun to see just who has joined the party.
Stewart Janes is a biology professor at Southern Oregon University. He can be reached as firstname.lastname@example.org.