Tweets,
A great spring so far with lots of birds hitting the back year feeders.
One interesting note that seems to be a pattern.
Over the years, but strikingly so this year, it seems as if the black
headed grosbeak shows up fairly early. Soon, they are replaced by
evening grosbeak who descend in hordes (over a dozen at a time) for
about a week or two. Then the black headed grosbeak (usually about four
or five max) shows up again for the rest of the summer.
Most of the time there is very little more than a day overlap between
these two species. Rarely do we have much time when both species are at
the feeders.
Anyone have an idea of how this works?

Jeff Osmundson
Arlington, WA