thumb|Anas acuta

The pintail or northern pintail (Anas acuta) is a duck species with wide geographic distribution that breeds in the northern areas of Europe and across the Palearctic and North America. It is migratory and winters south of its breeding range as far as the equator. Unusually for a bird with such a large range, it has no geographical subspecies, although the possibly conspecific duck Eaton's pintail is considered to be a separate species.

The Northern Pintail is a large duck, and the long central tail feathers of the male give the species its English and scientific names. Both sexes have blue-grey bills and grey legs and feet. The drake is more striking, with a thin white stripe running from the back of its chocolate-coloured head down its neck to its mostly white underparts. The drake also has attractive grey, brown, and black markings on its back and sides. The hen's plumage is more subtle and subdued, with drab brown feathers similar to those of other female dabbling ducks. Hens make a rough quacking sound and the drakes a flute-like whistle.

The Northern Pintail is a bird of open wetlands that nests on the ground, often some distance from water. It feeds by dabbling for plant food, adding small invertebrates to its diet during the nesting season. It is highly gregarious when not breeding, forming large mixed flocks with other duck species. This duck's population is affected by predators, parasites and avian diseases. Human activities, such as agriculture, hunting and fishing, have also had a significant impact on numbers. Despite this, the species is not globally threatened due to its large range and abundance.

Taxonomy

This species was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae as Anas acuta. Within the large dabbling duck genus Anas, The specimens were collected by J. V. Arundel in Sydney Island (Manra Island), Phoenix Islands in 1885 and came to the Liverpool national collection via Canon Henry Baker Tristram's collection which was purchased in 1896. Breeding takes place between April and June, with the nest being constructed on the ground and hidden amongst vegetation in a dry location, often some distance from water. It is a shallow scrape on the ground lined with plant material and down.

In the Palaearctic, there has been a decline in breeding populations across much of the region, including Russia, where the species has its population stronghold. In other regions, populations are either stable or fluctuating.