"The winter months," says Michael Morgan, "are when the highest percentage of Washingtonians visit the zoo." And for good reason: They can escape the masses of tourists that pour into Washington in the spring; the zoo is not crowded now.

If you're seized by a sudden yen to visit the zoo, some recent additions, according to Morgan: a pair of baby gorillas on loan for three years from the Milwaukee Zoo and, for the first time in 15 years, a hummingbird exhibit (in the Reptile House). In inclement weather, winter visitors can watch the animals being fed indoors (3 p.m.), and when it's nice, they can watch Hsing-Hsing and Ling-Ling, the zoo's giant pandas, cavort outdoors. "Visitors can have them almost all to themselves," says the National Zoological Park information specialist. "They even can watch them munch their brunch each morning at 11 a.m."

Half the zoo's residents are housed indoors, including the latest arrival, a Malayan tapir. "It's akin to the horse and rhinoceros, but looks more like a pig."

A reminder: Zoo buildings are open during the winter from 9 a.m. to 4:30 p.m. A bimonthly newsletter published by the Friends of the National Zoo (FONZ) keeps members informed with feature articles and announcements of upcoming events. Membership in FONZ, which includes admission to special activities, is $12 for people over 60 and under 12; individuals, $20; couples, $25, and families, $30.

Upcoming (free) zoo events:

*March 2, 10:30 a.m. to 3:30 p.m., a special exhibit and activities centered on seals.

*March 16, noon-3:30 p.m., "Tropical Heat Wave," featuring films, entertainment and an introduction to tropical forests.

To speak with someone concerning upcoming zoo activities, call (202) 673-4717. For a recorded announcement of zoo hours and other information: (202) 673-4800.