The smaller is about 4 1/2 inches square; the larger about 8-by-7-inches. The large ones accommodate the bigger woodpeckers, two at a time, one on each side. Unless of course, one is feeling testy and ...

The research appears in the October issue of The Auk, the scientific journal of the American Ornithologists' Union, and the cover features a painting of the woodpecker by graduate student Evaristo ...