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Find out about fall

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A naturalist's guide to fall in the region

By Metro naturalists James Davis and Deb Scrivens

September

This is one of the busiest months for bird migration, so there are many opportunities to see large flocks of birds gathering for their long journey or passing through.

Certainly one of the most spectacular opportunities of this kind is the huge flock of Vaux’s swifts that roosts in the old smokestack at Chapman Elementary School in Northwest Portland. Almost every evening during September, thousands of these speedy little birds fly down into the Chapman chimney to sleep, hanging on the inside of the brick walls. Walk up Northwest Pettygrove Avenue from Northwest 25th Avenue to Wallace Park where you can sit on the grassy hill overlooking the chimney. Arrive about half an hour before sunset and join the festive crowd waiting for the show. The peak is generally in the middle of the month.

Our region is a major wintering area for tens of thousands of waterfowl – ducks, geese and swans. They start to arrive in large numbers toward the end of the month and continue through October until the swans finally make it in November. Probably the most noticeable are the big flocks of Canada geese, honking loudly as they fly overhead, often in the classic “V”-shaped pattern.

Some birds form winter flocks for the added protection that comes from many eyes and ears being on the alert for predators at one time. Many insect-eating songbirds actually form flocks made up of several different species. Any forest is a good place to look for these mixed flocks of small passerines (or perching birds). On a walk in a conifer forest you might hear a string of soft, silvery notes descending from an area about halfway up the trees. Look up and watch for movement and you will most likely see golden-crowned kinglets, red-breasted nuthatches and chickadees flocking together. Other good possibilities are brown creeper, ruby-crowned kinglet and downy woodpecker. If there are enough deciduous trees around, you can add yellow-rumped warblers and sometimes Townsend’s warblers and bushtits to the mix. If you stand very still, these flocks of little birds may get quite close to you.

Don’t forget to look for that old harvest moon, the full moon closest to the fall equinox. It’s easy to see how this moon got its name; farmers could work well into the night by its light.

October

The true arrival of autumn is in October when the leaves of deciduous trees change color and many start dropping. The fall colors we see were there all along but were masked by the overwhelming amount of chlorophyll in the leaves. As winter approaches, much of the chlorophyll migrates into the trunk and roots of the tree (to be stored for winter) and the rest dies, revealing the other pigments in the leaves. If you come to Smith and Bybee Wetlands Natural Area just after a big leaf fall of golden cottonwood leaves, the trail looks like the Yellow Brick Road.

Migrating salmon can be viewed in the autumn in several local streams and rivers when the water is low and clear. Steelhead, coho and fall Chinook all migrate back to their spawning grounds in the fall. Watching these huge active fish choose mates and defend their nesting area is one of the most exciting nature shows offered in the Northwest at this time of year.

Spawning grounds offer the best viewing opportunities, as the fish stay in one area, often in shallow water, for days at a time. Look for areas in the river, known as riffles, where the water is rapid with small, choppy waves. Look closer and watch for movement. Fall Chinook often develop patches of white fungus on injured areas, so a flash of white moving in the water may be your first clue that the fish are present. Salmon can see movement above water and sense vibrations, so be sure to move slowly and quietly if you want to get a good look. A great opportunity for viewing is at Salmon Homecoming at Oxbow in October.

The Northwest also is famous for the explosion of mushrooms that occurs in the fall. Our region is blessed with some of the best edible mushrooms in the world and many Oregonians have taken the time and care to learn where to find and how to identify choice edibles. There are no general rules for knowing if a particular fungus is edible; you have to identify exactly what species it is to be safe. Metro and other organizations offer mushroom classes in the fall and the Oregon Mycological Society has programs, field trips and an annual mushroom show at the World Forestry Center.

November

In the ancient Celtic calendar the first day of winter was Samhain on Nov. 1 or 2, not the winter solstice on Dec. 21 or 22. To many Northwest naturalists this makes sense. By early November, we have definitely settled into the beginning of winter, and the end of December seems about right for the middle of winter. The ancient feast day of Samhain lives on today as Halloween in the United States and as Los Dias de los Muertos in Mexico.

At this time of year, you should have the regular gang of winter birds hanging out at the bird feeder in your yard. Don’t have a bird feeder? Keep an eye out for bird feeder building workshops offered by Metro in the fall. At any bird feeder in town, you can expect to see house finch, house sparrow, song sparrow, dark-eyed junco, spotted towhee, scrub and Steller’s jay, and black-capped and chestnut-backed chickadee. Depending on your location and whether you put out suet or not, you could also get bushtit, white-crowned sparrow, downy woodpecker and those hard-to-identify American goldfinches in their drab winter plumage. Two birds that are strictly winter birds and may not be present if it’s not cold enough are pine siskins and the exotic-looking varied thrush.

By November, most of the birds that spend the winter in the Portland area are here for the next four months or so. Tundra swans regularly can be seen at Fernhill Wetlands, Jackson Bottom, Sauvie Island and Ridgefield National Wildlife Refuge. The wintering bald eagles have arrived to join our increasing population of year-round resident eagles and can usually be seen at Smith and Bybee Wetlands Natural Area as well as the sites mentioned above. Learn how to identify our wintering waterfowl and birds of prey at Metro’s evening bird classes and weekend field trips to Smith and Bybee Wetlands Natural Area.

See for yourself

For more information about visiting Metro parks and natural areas with a naturalist, check out the Metro GreenScene... More