Reproduction

The northern pintail pairs monogamously, although males become highly promiscuous during the breeding season. Favored nesting areas are in damp grasslands and agricultural fields, on sandy flats, or on lakes, marshes, or ponds. The female constructs the nest in a concealed location on the ground, using dry grass and leaves. Down is added when incubation begins. Six to nine olive eggs are laid, and are incubated by the female for 22 to 25 days. Once incubation has begun, the male deserts the female and joins other male pintails to begin the annual summer feather molt. The young are tended by the female until fledging (e.g., attain flight), which occurs at 36 to 57 days of age.

Ecology

Northern pintails, like mallards, feed commonly in harvested upland cornfields in the upper Chesapeake Bay region, as well as those in low-lying or shallow-flooded areas. Food habits data from hunter-harvested pintails in the 1970s, showed that corn made up over ¼ of the total; volume of the 52 plant and 8 animal foods identified in pintails. As with other waterfowl, very likely some of the corn was taken as feed or bait. Northern pintail feed heavily of widgeon grass, redhead grass and Eurasian watermilfoil (C. Rawls, Univ. of Maryland, Solomons).

From a continental perspective, the northern pintail's diet is 90% vegetation, and 10% animal matter in winter, switching to 55 to 75% animal matter during the breeding season. Typical foods taken include seeds and grain, and the leaves of aquatic plants. Animals eaten include aquatic insects, crustaceans, snails, and the occasional tadpole. Ducklings eat more animal than vegetable matter, because they need more protein for growth than do adults.

Mink, raccoons, skunks, foxes, crows, gulls, and various species of raptors often eat the eggs and young of the northern pintail. Foxes, coyotes, hawks, and owls may predate nesting females, and individuals in migrating flocks may be picked off by peregrine falcons, northern harriers, and red-tailed hawks.

Redheads, ruddy ducks, mallards, common goldeneyes, and blue-winged teal have all been known to lay their eggs in northern pintail nests.

The northern pintail is susceptible to bacterial diseases, such as avian botulism and avian cholera. Of all northern pintails found dead, 46% had died of botulism, and 22% of cholera. Protozoan diseases are also common, the most serious of which is Leucocytozoon simondi, a blood parasite that is not fatal to adults, but may be to ducklings.

Most other sources of mortality or reduced breeding success are anthropogenic, and northern pintail populations have declined dramatically in recent years, from an estimated six million in the 1970s, to three million in the early 1990s.

Hunters still bag large numbers of pintails, but this accounts for less than 10% of the adult population per year. Pesticide contamination of habitat also appears to have only a small effect on northern pintails. However, the drainage of wetlands has been a continuing problem in both breeding and wintering areas, and thousands of nests are lost each year when they are destroyed by farm equipment.

Behavior