The Birding Year in the Pacific Northwest
January: Surviving Winter
Written by Andy McCormick
Andy McCormick, Volunteer and Former Board President of Eastside Audubon
On a quiet November morning, two days after the strongest windstorm to hit the Seattle area in nearly 40 years, my co-leader Lori and I were guiding a bird walk for the Bellevue Botanical Garden as part of the Lost Birds Project. Larger than life sculptures of five extinct birds: Health Hen, Carolina Parakeet, Passenger Pigeon, Great Auk, and Labrador Duck were on display in the garden. The storm was caused by what meteorologists called a “bomb cyclone,” a weather event in which a low-pressure area turns into a raging storm as the pressure drops quickly drawing air into its center causing high winds.
The topic of bad weather was on the mind of many in the group that morning. One participant asked, “When the wind is so strong, where do birds go?” My quick answer was, “Wherever the wind blows them.” This led to a discussion of how birds survive winter, which the first big storm of the season foretold the coming of rainy, cold, and blustery northwest weather.
Most birds cannot counter a windstorm and do get blown along with the wind. This phenomenon is well-known to birders, some of whom track storms to try to find birds which may have been blown into their area and be a rare sighting for them. Many birds survive winter by using a variety of means to do it. Chickadees and other small birds will often huddle together in a tree cavity or an old woodpecker nest hole. Sparrows and juncos will bury themselves deep in shrubs or in grass to avoid wind and cold. Many birds migrate and leave the wintery areas entirely. Long-distance migrants will fly for days or weeks over hundreds or thousands of miles to southern states or to other countries. Regional resident birds often make shorter migrations out of the hills and mountains to the lowlands or the coast in what are known as altitudinal or lateral migrations.
ALTITUDINAL MIGRANTS
January in the Pacific Northwest can be difficult for many perching birds. On the west side of the Cascade Range the weather is wet, windy, and the skies get dark early. Snow blankets the Cascades from British Columbia through Washington and Oregon highlands, and in parts of the Columbia Basin, a lobe of the high desert Great Basin that extends into central Washington and northeast Oregon, where high winds, snow, and freezing temperatures are common winter features.
Spotted Towhees, Song Sparrows, Pacific Wrens, Red-breasted Nuthatch, and Steller’s Jay are some of the resident birds of the Pacific Northwest region. They are considered resident birds because they do not vacate their entire breeding range, but they often change environments with the seasons by making short migrations. We can think of them as changing residences by ascending into the mountains during their breeding season and dropping down to the lowlands in fall and winter.
Some researchers suggest that altitudinal migrants are birds of the lowlands and move into the mountains during breeding to take advantage of food sources in an area where there is less competition from other birds. Usually, as elevation increases, the number of birds decreases. However, other reviewers take the opposite view and consider the birds as primarily high-altitude breeders with the motivation to descend out of the mountains as an escape from wintery conditions. It is likely that these birds have evolved this annual pattern of living in two habitats in much the same way that the long-distance migrants do to seek the best conditions at any given time of the year. They just do not travel as far.
WHAT WE KNOW ABOUT ALTITUDINAL MIGRANTS
What we know about altitudinal migrants is limited by the lack of attention they have received from researchers. We do have some information on the frequency with which birds change elevation. In her 2017 paper “Altitudinal Bird Migration in North America” (The Auk and BioOne) W. Alice Boyle reports that 116 bird species in the USA and Canada undertake altitudinal migrations. This represents 20% of the continental species in the study, and 30% of the continental birds which overwinter in the USA and Canada. The west was home to half (58%) of the 116 species that engage in altitudinal migrations in North America. Acknowledging that most of North America’s high mountains are in the west puts that statistic in perspective.
Most of the research on altitudinal migrants has been done with tropical birds. In the tropics, fruit-eating birds must eat more frequently and in their search for food make more movements during the year. Some of these movements involve moving to higher elevation. There is less competition at high elevations in the tropics, too. However, food may not be the only motivation.
There appear to be multiple processes influencing why some birds change elevation and others do not. Food scarcity in winter at high elevations and climate in winter snows and ice prevents birds from accessing food even if it is available encourage birds to move to lower elevation. With fewer predators at higher elevation, nesting upslope may have an advantage in avoiding predation.
This discussion raises the question in my mind. I wonder if altitudinal migration is a new phenomenon in North America since the retreat of glaciers exposing high elevation habitats for the past 10,000 years. We see some of this movement today in pioneering birds such as Black Phoebe and California Scrub-Jay expanding their range northward as the planet warms. Steve Hampton in Birding magazine (December 2022) reviews National Audubon data to show how birds are expanding their range northward in response to climate change. He reminds us that information collected by birders is vital, and it is important to act now to help birds cope with the changes that are already underway. He urges us to pay attention. “The birds are showing us what is happening to our world.”
LATERALLY MOVING GULLS
During the course of the year, several gull species considered as resident in the Pacific Northwest also make changes in their habitat. Instead of a change in altitude, these gulls make lateral migratory movements. Western Gulls move to coastal islands in spring to breed. California Gulls breed in the interior east of the Cascades and Rockies, but in winter, they move southwest. Some California gulls remain around the river valleys of British Columbia, Washington, Oregon, and Idaho, but most vacate their breeding area and migrate west to coastal California, and some remain around Puget Sound. Also breeding in the interior, Ring-billed Gulls are more widespread. They move west and south, and large numbers overwinter in the Puget Sound and coastal regions.
Western and Glaucous-winged Gulls are primarily coastal breeders, and they will make a lateral move inland during winter months. Most Western Gulls remain along the coast, and a few may winter in the Puget Sound area, hanging around with Glaucous-winged Gulls which also move back to Puget Sound and some inland areas in winter.
A third large white-headed gull, Heerman’s Gull moves north from it southern breeding area in summer, and flocks can be found in coastal areas and along other waterways. Their white head and red bill contrasts with their gray body making them a stand-out among other PNW gulls. The immature Heerman’s Gull is all gray and stays with the adults. Iceland Gull is another longer distant migrant that breeds in northern Canada. Only a few of these gulls will be around western waters in winter.
Three additional gull species arrive along the west coast in October, contributing to gull variety in winter and bringing the suite of gulls to a total of eight species in winter. Bonaparte’s Gulls with their flashing white primaries are in the area during spring and fall migration and some winter in the region. The yellow-legged Short-billed Gull has black and white wing tips and a slender straight bill. It migrates from the Arctic breeding ground to winter along the coast and Puget Sound from September to April. Sabine’s Gull is ocean-going and most commonly seen on pelagic trips out of Westport, WA in spring and fall.
WESTERN X GLAUCOUS-WINGED GULL (HYBRID)
Complicating identification of gulls in the Pacific Northwest is the ninth gull that requires our attention. It is the regional hybrid of the Western Gull and Glaucous-winged Gull. (This hybrid is noted in eBird as Western X Glaucous-winged Gull (hybrid) and I will follow that convention here.) The hybrid or intergradation zone of these two gulls extends from southern Oregon to southeastern Alaska.
This hybrid is widespread and will often be the most common gull in many large mixed flocks of gulls in winter. In past conversations, Carol Riddell, a long-time birder in Snohomish County, WA referred to the gull mix as a ”free-for-all zone of hybridization.” Mike Donahue of Seattle has taught classes on gull identification for many years. He described the challenge as “trying to identify gulls amidst a hybrid swarm.” Donahue added in all caps, “WE ARE TAUGHT THAT HYBRIDS ARE RARE, BUT THIS HYBRID GULL IS NOT RARE.” In fact, it is so prevalent in the region that it has been locally named the “Olympic Gull.”
Bill Tweit, eBird reviewer and co-author of Birds of Washington (2005) summed it up in an email, “The presence of intergrades creates two sets of problems for birders: By their presence they increase the number of identifiable forms that a birder must contend with, and the identifiable forms that they create are messy, often difficult to categorize in the field.” He advised not worrying about making mistakes in identifying gulls. Many birders agree it is helpful to watch gulls with other people and discuss the differences while in the field.
JANUARY BIRDING
Visitors from the eastern states take note that gull flocks in the west are often a mix of several gull species, unlike in the east where a single species such as Herring Gull may dominate large flocks. The Olympic Gull often appears like a Herring Gull, but it will have a wide variety of plumages resulting from hybridization and back crosses, and most of them will have a dark eye, unlike the Herring Gull which has a light-yellow eye.
In winter, expect birds to be in different places than when we see them in summer. These changes help birds find food, avoid the worst weather conditions, and allow them to seek safety. Good fortune comes to those who are prepared and in winter, to those who expect the unexpected when it comes to birds.
SUGGESTIONS FOR FURTHER READING
Boyle, W. Alice (2017). Altitudinal Migration in North America. The Auk, 134(2): 443-465.
Hampton, Steve (2022). Ornithology in the Anthropocene. Birding, Vol. 34, No. 7, pp. 32-39.
McCormick, Andrew (2021), Gull Identification in the Pacific Northwest, Parts 1 and 2. WOSNews, #189 and #190, Washington Ornithological Society.
Photo Credit by Mick Thompson