Tufted Ducks (Aythya Fuligula) are the only Pochards with a long, pendent crest. They are neat, boldly patterned, black and white birds with delicately rounded heads. The thin, loose, drooping hind crown crest can be inconspicuous at times, the female crest is often not visible at all. The lowland ducks inhabit a variety of wetlands that need not support dense emergent vegetation - waters with excessive amounts of floating plants are shunned altogether. The southward expansion of the breeding range and their spectacular numerical increase reflect a propensity to rapidly colonize reservoirs, gravel pits, fish ponds and marshland ditches. Tufted Ducks (Aythya Fuligula) become remarkably confiding on urban waters. The ducks are highly gregarious throughout the year, wintering flocks mayexceed thousands, when the ducks frequently doze in compact rafts. Very active on the water, they continually jump-dive and bob to the surface. Often mixing with other wildfowl, feeding flocks of a hundred or more are not unusual. The ducks easily dive to 50 feet, although shallower depths of 10-15 feet are preferred. Bottom stones may be flipped over to expose food items, and the pochards capitalize on dead or moribund fish. Molluscs possibly constitute up to 80 percent of their diet, and inch-long mussels are easily ripped loose and swallowed whole. They feed by day and night, sometimes even on the darkest nights. Breeding Tufted Ducks (Aythya Fuligula) can be highly colonial, particularly on islands. Pairs often breed adjacent to marsh-nesting gulls or terns because the defensive birds drive off jackdaws and other egg thieves. Dump-nests sometimes exceed 20 eggs, and females may parasitize Common Pochard (Aythya Ferina) nests. Hatching normally coincides with the emergence of aquatic insects on which ducklings are greatly dependent. Rarely, offspring are abandoned when only several days old, but even tiny ducklings can survive if they weather remain favorable. Though not typical, broods do merge, and progeny are usually independent prior to fledging, often as early as four weeks of age if the female molt is imminent. Pike constitute significant duckling predators.