RIGHT NOW we have about 35,000 Canada geese," said Jerre Gamble, assistant manager of the Blackwater National Wildlife Refuge near Cambridge, Maryland. "That's about midpoint; we should have 55 to 60,000 by Thanksgiving."

"You can walk up quite close to the geese," says Lola Oberman, who runs field trips for the Audubon Naturalist Society. "They're usually strolling right past the visitors center at Blackwater, so you don't even need binoculars. It's a good family activity."

November may be the perfect month for families, hardcore birders and those who like birds but don't know much about them to come to the Eastern Shore, particularly to the Blackwater and Chincoteague refuges. Migrants are passing through in great numbers, and many birds that spend the summer here haven't left yet. There are, for instance, still a few great blue herons around.

This is also a good time to catch the mavericks, off-course juveniles that somehow wind up on the Eastern Shore instead of Texas or England or wherever. "I submitted a really incredible bird I saw on the Eastern Shore for review by the Maryland Bird Records Committee last year," says ornithologist Claudia Wilds. "It was a black-tailed gull, which breeds in Northern Japan and Eastern Siberia. I don't know, maybe it hitchhiked on a shipload of Toyotas."

Sightings of such exotics are the home runs of birding; the record books at Blackwater and Chincoteague are heavily sprinkled with reports of unusual species, with supporting confirmations and skeptical disputations.

The availability of expert advice is one of the advantages of birding on the refuges, though they are by no means the only places to see birds. Canadas are all over the Eastern Shore, gleaning corn and soybeans spilled by mechanical harvesters. "They feed at both ends of the day, unless there's a lot of moonlight," Gamble says. "Then they go out at night."

"You've got to watch the moon," Oberman adds, "because after a night feeding, the geese spend the next day sleeping it off, and there's not one around to see. It can be really spooky."

Watching for feeding Canadas is a good way to keep the kids quiet on the two-hour drive to Blackwater. Oberman likes to stop off at the marina just before Cambridge "to see all kinds of ducks, geese, and swans, which come in November. Sometimes you can see loons diving."

But the refuge itself is a great place to see, not just the odd occasional bird, but great sky-crowding congregations. The geese are almost constantly on the move, "because they see the eagles patrolling overhead, and get stirred up," Oberman says. That's bald eagles she's talking about -- Blackwater shelters a population of roughly 50.

Chances of seeing one of these living American symbols are good, but not guaranteed. "There's one real show-off who likes to perch on a snag right outside the visitors center," Oberman reports. Others hover near the wildlife drive, a five-mile road open only to motorists (automobiles disturb the birds much less than hikers or bikers). It's a good place to see the Canadas and watch the multitudes of dabbling ducks tip up their tails as they dip for food; in deeper water are the diving ducks, which disappear here and pop up over there.

Those who'd rather walk can take a left beyond the first pond, leading to a picnic area and nature trail. Be on the lookout for Delmarva fox squirrels, an endangered species of great gray creatures with ostrich-plume tails -- or brownheaded nuthatches, although Oberman says the best place to spot the latter is near the picnic grounds.

The woodland trail leads to an observation tower from which, with binoculars, you may see eagles walking over the mudflats, "strutting along like gorillas and feeding on fish," Oberman says. Alongside you may see snipe, "shorebird types with stripey heads and great long beaks they use for poking in the mud," Oberman says. "They go wherever the snow geese have eaten away the vegetation."

The 28,000 snow geese expected at Blackwater are chiefly of the "blue phase," a dark-bodied central Arctic race. At Chincoteague, two more hours down the road, most of the snows are snow-white but for their wingtips, and hail from Greenland and the eastern Arctic.

The difference between Blackwater and Chincoteague is the difference between a Bay community and an ocean one, says Wilds, a research collaborater with the Smithsonian who wrote the book on the subject: Finding Birds in the National Capital Area (Smithsonian Institution Press, 1983, $10.95). Three days every weeek since 1974 she has conducted a census of Chincoteague's birds for the International Shorebirds Survey.

"Because it's on the Bay, Blackwater gets migrants much more often from the center of the country," Wilds said. "Chincoteague's come from the Northeast.' Chincoteague, an island village, and Assateague, the neighboring barrier island that is the actual refuge, are breeding grounds and stopovers for many shorebirds, Wild's specialty.

She has a set path for the survey, including a ten-mile hike. But if she were doing it for fun, this is what she'd try:

"First, I'd check the tides; Channel 9 (the local cable station) or either of the visitors centers can tell you when low and high tides are due. It can make a big difference on when you go to different places."

Then, binoculars in hand, she'd walk the Pony Pen Trail early in the morning, looking for songbirds and woodpeckers. Brownheaded nuthatches are here as well as at Blackwater, "curling around the cones from the loblolly pines," she says. "One birder says they sound like a squeaky rubber duckie; they're easier to find if you can hear them."

If low tide comes in the morning, she'd try to hit the mudflats of Tom's Cove on Assateague's south end. There you can see sea ducks like the red-breasted mergansers, birds with ''skinny bills with saw-like edges," she says. There's also a good-sized population of brant, which look like miniature, "rather dainty," Canada geese.

A morning low tide's also the time to catch oystercatchers working the oyster beds in the channel between Chincoteague and Assateague. "They have chisel-like bills," she explains, "and when an oyster is partially exposed and gaping open, a talented oystercatcher can cut its muscle. Sometimes the oyster clams up, so to speak, and you'll see a poor oystercatcher with one clamped onto its bill."

The ocean she saves for the afternoon, when the light is best, and the closer to low tide the better. "I counted 21 species of shorebirds there recently," she says. "It's one of three top areas in the country for migrating shorebirds to stop and feed. But be sure to dress warmly."

The three-mile wildlife drive near the National Park Service Visitor Center at Assateague is a good place to go in the afternoon because after 3 it's open to cars. The loons and tundra swans may be there, along with dabbling ducks, Canadas, and those white snow geese.

There are many other birds that may surprise you at Chincoteague -- the refuge harbors a few bald eagles, and Wilds has seen a sage thrasher there as well, far away from its native western plains. You can easily spend a whole day just trying to sort out the shorebirds.

BLACKWATER NATIONAL WILDLIFE REFUGE -- From U.S. 50 just east of Cambridge, turn south on Md. 16 to Egypt Road. Look for bluebirds on your way to the refuge. Egypt Road ends at an unmarked road (Key Wallace Drive); turn right and go 1.3 miles to the Wildlife Interpretive Center. The refuge is open dawn to dusk; visitor center hours are 9 to 5 weekends and 7:30 to 4 weekdays. For more information: 301/228-2677.

CHINCOTEAGUE NATIONAL WILDLIFE REFUGE -- Take U.S. 50 east to U.S. 13 south at Salisbury. At T's Corner, take Va. 175 east to Chincoteague. Go over the bridge and turn left onto Main Street, then right on Maddox Road. The refuge is open dawn to dusk; visitor center hours are 9 to 4. For more information: 804/336-6122. THINGS TO BRING

* Extra warm clothing, especially if you plan to walk the beach at Chincoteague or climb the observation tower at Blackwater.

* A pair of binoculars. Prices range from $25 to $1,000, but ornithologists recommend that you buy at least an 8-power (that is, the object is magnified eight times). It should be weather resistant.

The National Audubon Society endorses the 8x36 -- 8-power, 36-mm objective (the diameter of the large end of the glass) -- made by Bushnell, a division of Bausch & Lomb. It has a list price of $260 but sells for considerably less in discount stores.

* A spotting scope. Truly serious birders who are interested in ducks and waterfowl -- "the kind of birds who stay still for a while," says Lola Oberman -- eventually purchase one of these telescopes.

"The big disadvantages are that they're not as bright as binoculars, which is bad if you're out in the early morning, and anything more powerful than 8 is very sensitive to any slight hand movement," says Allen Zweig of Penn Camera Exchange. "So they have to be used with a tripod, which is bulky, and focused on birds who don't flit around."

Spotting scopes run anywhere from $200 to $2,000; the most popular at Penn Camera is a Bushnell Spacemaster which has 15- retail price of $395.

* Field guides. Oberman and Claudia Wilds have the following suggestions:

Chandler S. Robbins' Birds of North America, Expanded, a Golden Field Guide, Western Publishing Co., NY, 1983, $7.95 paper. "This is the simplest and best for the beginner," Oberman says. "It has range maps right next to the bird so you can see at a glance if you've got the likely one."

Roger Tory Peterson's A Field Guide to the Birds: A Completely New Guide to All Birds of Eastern and Central North America, 4th Edition, 1980, Houghton Mifflin, Boston, $15 ($10 paper). "This is the most restrictive -- they won't show birds west of the Rockies," says Wilds.

National Geographic Field Guide to the Birds of North America, edited by Shirley Scott, National Geographic Society, 1983, $13.95 plus postage and handling, available only from the society downtown or the Audubon Book Store in Chevy Chase. "This is better for the sophisticated birder and goes into a lot more detail," says Oberman.