JOSEPH – I have already featured the mountain chickadee as a bird of the month, but now that winter has arrived, there has been a change in the chickadee population in our backyard.

Apparently, there has been a large migration of black-capped chickadees from more northern climates, so they now outnumber the mountain types about three to one, so they are my choice for bird of the month. The one in the photo has a sunflower in his beak.

Black-capped chickadees are very gregarious as they travel through the forests accompanied with nuthatches, kinglets, brown creepers and two other species of chickadees. Which brings me to a subject that has always been a mystery to me, and that is why different species that are so alike in almost every way never interbreed when nesting season comes.

A case in point is the kinglets. The ruby-crowned kinglet is almost undistinguishable from the golden-crowned kinglet except for a splash of color on top of their heads, yet they never interbreed.

Once I was on a field trip to study birds in Eastern Oregon with a van of people. Among them was a lady who was a community college professor who had a degree in biology. I asked her how she could identify the numerous species of field sparrows that we were observing all along the way.

Her answer was, “I call them LBJs.” When I looked puzzled she said, “Little brown jobs.” So much for avian expertise.

E.H. Van Blaricom’s column runs monthly in The Observer.