All winter and early spring, the resident Canada geese, of whom there are fewer than a dozen, have pretty much hung around the sanitation dept. pier, leaving the rest of the river to everyone else. Now, though, it's nesting season. Suddenly, they're swimming far and wide, feeding everywhere, paddling around between pilings, and generally making a show of strength. The Brant geese have numbers -- 50 or so -- but they're much more timid. If they're intending to breed around here, and not just eat, they're going to have to be pretty sneaky about finding nesting sites. Meanwhile the mallards are swimming in pairs of males or pairs of females, which says to me they've built their nests already, and one of each couple will be always there from now on until the eggs are laid and hatched. That's one way to protect your property. Yesterday being a beautiful Sunnday, the park was thronged with people, including many many picnickers on the lawns. This morning the lawns were hopping with birds -- sparrows, robins, thrushes, grackles -- feasting on dropped crumbs. Got to love this ecosystem.