The snow geese, trumpeter swans and tundra swans are back, sure signs of midfall. And a sure sign that some readers are asking, “How do I tell the difference?”

One way is to think of a trumpeter swan as an aircraft carrier and the snow goose as a destroyer. A trumpeter swan runs about 4 feet long with a 7-foot wingspan; a snow goose is about 1½ feet long with a 3½-foot wingspan.

The medium-size snow goose, generally smaller than a Canada goose, has black wingtips best seen in flight. They like to travel and can be seen in groups of a thousand or more. The sound of foraging, gregarious snow geese filling the airways is one you won’t forget.

But wait! Those large white birds might be tundra swans. Both are all white, are 4 feet or longer (trumpeters are slightly larger), and weigh about the same.

When bird-identification guru David Sibley takes more than a thousand words to detail the difference between tundra and the rarer trumpeter swans, and concentrates on their black bill sizes (trumpeter longer and all black) and eyes (tundra eyes seem to stand apart from the bill) as a definite ID, what’s the casual bird-watcher to do?

The trumpeter is larger than the tundra, but who can tell when you see only one species? Sibley suggests movement as a possible tool, and if you’re without binoculars, that’s your best bet.

The larger trumpeter moves more slowly than the more agile, quicker tundra. Another key is the voice: the gentle honks of a trumpeter and the higher bugling of the tundra.

Bird-watchers are very fortunate to have all three in Western Washington, trumpeters and tundras from November to April, snow geese from mid-October until sometimes as late as mid-May.

Snow geese arrive in the tens of thousands, almost all of them taking up winter residence around the Skagit River delta. These are the large flocks that you can see from the roads on Fir Island, near La Conner.

Trumpeter swans also populate the fields and estuaries; tundra swans the fresh- and saltwater habitats, with about 2,000 in Skagit County.

More about trumpeters: Wildlife biologist Martha Jordan with the Trumpeter Swan Society is giving two slide presentations about these birds at 10:30 a.m. and 1:30 p.m. Dec. 1 at Christianson’s Nursery, 15806 Best Road, Mount Vernon.

Get a free swan identification pamphlet to help you distinguish the birds of the Skagit area. The talk is free, but reservations are required by calling 360-466-3821. See www.christiansonsnursery.com for more information.

Speaking of birds: Hundreds of sandhill cranes are being seen along the Lower River Road in the Vancouver Lake lowlands. A good guide to scoping out fall and winter birds in that area is at www.vancouveraudubon.org/vanlake.html.

Chain up: If you’re visiting Mount Rainier National Park or Hurricane Ridge at Olympic National Park, don’t leave the tire chains at home. It doesn’t matter what the predicted weather or road conditions are, because both can change rapidly at higher elevations.

The rule applies to four-wheel and all-wheel drive vehicles. There will be checkpoints.

Looking forward: A new trail at Ape Caves has been started by the Washington Trails Association and the Mount St. Helens Institute. The trail will end at a Mount St. Helens viewpoint. The plan is to complete the trail by late next summer.

Columnist Sharon Wootton can be reached at 360-468-3964 or www.songandword.com.