Conifer diversity is great in our region, and I'll bet many of you have stopped along the highway to gather foot-long sugar pine cones. Cones often are used as decorations, and we have a tremendous variety to choose from.
Just over the hill near Redding, Calif., gray pines have large, spiked cones the size of cantaloupes. At the other end of the size spectrum are the tiny cones of western red and Port Orford cedars.
Let's start our table decoration with the cones from ponderosa pines. They are ruggedly constructed and about the size of a fist. Add some Douglas fir cones, somewhat less woody and about 3 to 4 inches long with bracts that look like the hind quarters of a mouse heading down a burrow. Now add the papery cones of a sitka spruce from the coast. Finally add the tiny cones of the western hemlock, also lightly constructed and about an inch long.
What are table decorations for us comprise a banquet for red crossbills. Knife, fork and spoon would hardly be the appropriate utensils for this feast. If you or I had to extract the seeds from the unopened cones, we might want a pair of pliers for the ponderosa pine cones and maybe tweezers for the spruce and hemlock. Even then you might get plenty hungry.
Red crossbills are finches related to purple and house finches but a little bigger. The male is brick red, and the female is yellowish green. The only tool available to the red crossbill is its unique crossed bill, but it is a very effective cone opener.
To open a cone, a bird bites sideways under the bract of a cone and moves the jaw sideways. This separates the bract far enough so the seeds can be extracted. If the bract is stubborn, the entire bill can be twisted, applying more leverage. If you are wondering, there are both right- and left-crossed crossbills.
Returning to our banquet of cones, I mentioned you might need both pliers and tweezers. This is not helpful to the crossbill. Each bird has only one bill, so it's either pliers, tweezers or something in between.
Just as cones come in different sizes, so do the bills of crossbills. Crossbills living in the ponderosa pine forests east of the Cascades have large bills, our pliers if you will. The crossbills at the coast that feed upon the papery spruce and hemlock cones have much smaller bills, tweezers. Their "kip-kip-kip" calls also differ and can be distinguished by an experienced birder.
Across North America, there are nine distinct forms of red crossbills, each with bills of a size that correspond to the size of the cones in the area. Now before you worry that you will have to buy a new field guide describing the almost imperceptible differences between the nine species, relax. Scientists have found genetic differences but not enough to declare a host of new species. We're safe for now.
Red crossbills usually are rare in the Siskiyous, but this winter we had many. They can be heard and seen flying in flocks over the foothills and sitting high in conifers. Which of the nine forms do these represent? Who knows? There is probably more than one. Good luck.
Stewart Janes is a biology professor at Southern Oregon University. He can be reached at firstname.lastname@example.org.