Seattle Post-Intelligencer: Years ago, the Anna’s hummingbird used to winter in the U.S. only as far north as California but now is a regular Christmas visitor to Seattle and throughout the Pacific Northwest. Climate change appears to be the reason. “They are more aggressive and displacing native species like the rufous hummingbirds,” said Matt Mega, conservation director for the Seattle Audubon Society. One method of tracking changes in bird migratory and wintering patterns is the annual Audubon Christmas Bird …