I spent the spring of 1983 censusing birds in the central Oregon
cascades. I spent every morning from mid-April through mid-June in old
growth forest stands from dawn until about 10 a.m. There was one morning
in mid-May when the stands were full of ruby-crowned kinglets. Dozens and
dozens of them at every census point. That was the only day we saw any
ruby-crowns; not a single one on any other day that spring.