Bats, beavers and a boat.

Those are the elements for a fun evening of nature-watching this Wednesday at Black Hill Regional Park in upper Montgomery County.

Aboard a pontoon boat, with the help of a park naturalist, you can cruise the 505-acre Little Seneca Lake, looking for bats and beavers. There are a number of beaver lodges in several small coves along the lake's banks. As the sun begins to set there's a greater chance of seeing some of the park's bats, said park naturalist Fawn Foerster (above, right). Maybe you will see little brown bats swooping in for a snack of mosquitoes (catching them at a rate of about one every six seconds), or big brown bats eating June bugs, grasshoppers and lightning bugs.

The evening cruise goes from 7 to 8:45 and is for ages 6 and older. The naturalist will have binoculars for everyone so you'll have a good chance of catching a glimpse of the normally shy beavers and bats. The fee of $6 per person includes a snack. There is a limit of 30 people on the trip. Call the park at 301-916-0220 for reservations. There are also bats-and-beavers cruises scheduled for July 29, Aug. 3, 4, 19, 24 and 25.