Alviso section of Don Edwards Wildlife Refuge

Overview: The ducks, geese, pelicans and egrets are only the most visible among the fascinating array of waterfowl hanging out near the Alviso Environmental Education Center of the Don Edwards San Francisco Bay National Wildlife Refuge.

The trailhead near Alviso on the southernmost edge of San Francisco Bay does have issues: one is the smell, thanks to an abundance of shallow, often-still water combined with the aroma of a nearby landfill.

Once your nose gets acclimated, however, you're ready for the chance to see more wildlife in an afternoon than you'd see in a month hiking the hills rimming the Bay Area.

Of course if you're interested in any wildlife other than birds, you could be a bit disappointed. But how could you complain about 280 species of avians numbering in the millions on their annual Pacific Flyway expeditions?

The trails on this 7-mile track are pretty basic: A section of the Mallard Slough Trail near the Environmental Education Center connected to a section of the Alviso Slough Trail.

The network of levees in this section of the refuge creates nearly boundless variations, depending on how long you plan to hike.

Best times to go: Migrations are heaviest in the spring and fall. Summer heat makes the hiking uncomfortable, but winter should be fairly nice.

Tips: Some trails are closed during waterfowl hunting season -- mind the signs posting the closing dates.

Use sunscreen and make sure you're wearing weather-appropriate clothing. Exposed areas of the bay can be very windy.

Don't forget your binoculars and photography gear.

Contact: (408) 262-5513

Hours: sunrise to sunset

Driving directions: From I-880 or Highway 101, exit on Highway 237 toward Alviso. Take the Zanker Road North exit and follow Zanker northbound to the Environmental Education Center entrance road (a sharp right turn at Grand Boulevard).