A duck who hatched her brood under the watchful eyes of the US Secret Service took swimmingly to motherhood Sunday, guiding her 11 ducklings unerringly to water with the assistance of at least three government departments. Fittingly for a duck who laid a clutch of eggs at the doorstep of the US Treasury department, she did it on public land, in Rock Creek Park, the forested ravine that bisects the capital.

?This is an excellent habitat. We?re happy to take her under our wing,? said Laura Illige, the park?s chief ranger. The duck, a common mallard, laid a clutch of eggs early last month in a mulch pile at Treasury, next door to the White House in downtown Washington. She quickly became a star tourist attraction on the busy pedestrian plaza. Treasury Department officials erected security barriers to shield the waterfowl from onlookers and from protesters during an international summit.

The fate of the mallard and her brood appeared to warm the icy hearts of bureaucrats and journalists eager for a diversion from fiscal policy. Government officials provided regular updates on security improvements and hatching plans. Television reporters interviewed bystanders in front of the nest and Treasury correspondents traded duck gossip. The ducklings hatched Saturday afternoon. Early on Sunday, a team of Agriculture Department wildlife specialists transported the family to the creek in a four-vehicle motorcade. National Park Service rangers met them and a Treasury official had scouted the location in advance.

The mallard and her ducklings regrouped without hesitation under a makeshift mesh enclosure. The hen, quacking loudly, probed the mesh and quickly discovered an opening, waddling straight for the fast-flowing stream. The ducklings followed in a tight line, bumping into one another in their nervous haste. When the mother duck reached water, all of the ducklings followed her in except one. The mother paddled upstream with her ducklings bunched in her wake, and circled back, gaining speed with the current. The straggler dove in, and, paddling furiously, rejoined the group, which made for a shady overhanging bank on the other side of the creek and quickly disappeared from view.

<B>Mark FELSENTHAL</B>