Recently, winter wrens and varied thrushes have retreated from the foothills to winter in the Sequim area, even before snow chases them down slope. But we haven't seen gray jays around, for example, as they can cope with snow.
How do the birds of the Olympic Mountains cope with deep snow? The most obvious strategy for dealing with it is simply to flee to a milder climate.
Some birds that live most of the year elsewhere come to the mountains to breed during mild-weather months. Hermit warblers, American pipits, horned larks and dark-eyed juncos do this.
The first two return to homelands in the south. Among the three subspecies of horned larks found in Washington, only the pallid horned lark even ventures into high mountains to breed. Juncos, too, winter in the lowlands.
The other four species commonly found on Hurricane Ridge in the summer - common raven, gray jay, red-breasted nuthatch and sooty grouse - stay throughout winter. Aside from surviving low temperatures, their obvious challenge is finding food. With snow piled high, foraging patterns of summer no longer are available.
Stash the cache
Two corvids - common ravens and gray jays - and red-breasted nuthatches use the strategy of food caching. Corvids, among the smartest birds in the world, are known for being able to remember the myriad places they have cached food. Caching is very much a secretive activity, no matter how sociable birds may be among their peers. Ravens have been seen watching other ravens, seemingly spying to learn the whereabouts of caches other than their own.
Gray jays, usually working as mated pairs, cache food in cracks and crevices in trees. Moreover, they use abundant sticky saliva, drawn from enlarged salivary glands, to paste food into less likely places in trees. These jays are thought to have cached sufficient food for the entire winter by the end of October. Ultimately, pairs will breed in early spring (March and April). They may even used cached food to feed nestlings.
Ravens cache in
Common ravens are instinctive cachers of all sorts of things. They have been observed to cache items during play when only a few days out of the nest. This activity helps prepare them for the serious business of food caching later.
A raven has a sizable pouch under its tongue, allowing it to transport a significant load of food, such as pieces of meat, in a single flight. This capacity lets it fly far afield to prey on carcasses, some of which are mammals trapped by deep snow. Ravens have been observed to cache a single load of food in multiple locations.
Hide from seekers
Nuthatches are known for having feet and claws suited to working downwards on a tree trunk. This ability lets them feed by finding insects in niches other foragers don't see into. Surely nuthatches use their unique upside-down positioning to cache food in places that gray jays, and other would-be robbers, aren't likely to find.
The remaining bird, sooty grouse, has no known ability to cache food. Given its familiar habitat in summer - alpine meadows - it seems to be a particularly unlikely candidate for surviving deep snow.
Its survival strategy is two-fold: It retreats from meadows to conifer forests, sometimes even moving higher in elevation. These grouse live in the trees, not on the ground. For food, they eat the needles of the trees around them.
Annual bird count
A quick way to see whether a species lives nearby year-round is to look at a "range map." Although such maps in most bird books often are too small for this purpose, a great resource exists online:
Seattle Audubon's BirdWeb Web site (www.birdweb.org) contains a large state map for each species - color coded to show areas in which a bird resides year-round or only during breeding season.
The Sequim-Dungeness Christmas Bird Count will be held Monday, Dec. 14. Join a team (contact Bob Boekelheide at the Dungeness River Audubon Center, 681-4076), or count birds at your feeder and report totals to Bob.
Dave Jackson is series coordinator and Web master. Send comments to him at editor@olybird.org or 683-1355. For more information, see Web site www.olybird.org.