What makes tropical birds visit Oregon in winter?
Frost is on the roofs, and snow is in the mountains. Yet, a little over a month ago I saw a bird along the Oregon Coast whose name invokes visions of palm trees, sunny beaches and iced drinks with tiny parasols. It was a tropical kingbird.
What is any bird with the name “tropical” doing in Oregon? And why would any insect-eating bird head north just when insect populations are crashing as winter approaches? Are these apparently confused birds doomed to starve or just seeking out a bit of adventure before returning to Mexico?
They look similar to the familiar western kingbirds that breed in southwestern Oregon and throughout sagebrush country to the east. Tropical kingbirds are brighter yellow on the belly. The bill is a bit larger, and they lack white in the tail. The more usual home of these birds are the utility lines on the coastal plain of western Mexico in places near Mazatlán and Puerto Vallarta, where they patiently wait to sally out after passing insects on hot and humid afternoons.
This visitor was not unique. Scattered tropical kingbirds visit the Oregon Coast every fall, and sightings are becoming more common. They have a history of visits going back at least five decades. Most appear in October and disappear by the end of the year. It’s unclear why they make this journey.
Tropical kingbirds are not the only birds from sunny climates that seem to be directionally challenged and drift north following breeding. White-winged doves are a desert species that breed among the saguaros of the southwest. They look much like our mourning and collared doves but with a white slash across their wings. They are not as regular as kingbirds along the Oregon Coast, but at least one individual shows up somewhere more years than not. White-winged doves have even been encountered in Jackson County at least twice.
Northward movements after breeding are not all that unusual. Some ibis, cormorants and herons end up in the strangest places. Species that breed no farther north than along the Gulf of Mexico occasionally end up in New Jersey and Minnesota. Locally, great egrets become common in the Rogue Valley after breeding elsewhere, mostly in California, and brown pelicans with their entourage of Heermann’s gulls visit the Oregon Coast beginning in July. The pelicans retreat to Mexico and Southern California by Thanksgiving. These visitors make more sense to me. Fish can be plentiful across North America at least until freeze-up puts a lid on the northern ponds and lakes and winter storms make fishing a challenge.
There are others that on rare occasions have abandoned the good life in warmer climates for a visit to Oregon, much to the enjoyment of birders. These have included vermillion flycatchers, pyrrhuloxia (a desert “cardinal”), and Costa’s hummingbirds.
Wings give birds tremendous mobility allowing them to travel great distances in a brief time. Even small birds such as migrating warblers regularly make jumps of 100 miles or more in a single night during migration. Larger birds can do much more. Some movements may be beneficial to a bird whether we understand or not, like the tropical kingbird, while others are simply mistakes. I am hoping the tropical kingbird I saw is now safely back in Mexico.
Stewart Janes is a biology professor, emeritus, at Southern Oregon University. He can be reached at firstname.lastname@example.org.