Nelson's sharp-tailed sparrow  (Ammodramus nelsoni)

Nelson's sharp-tailed sparrow is classified as Least Concern (LC) on the IUCN Red List (1).

Nelson’s sharp-tailed sparrow (Ammodramus nelsoni) is an extremely secretive bird of North America. Prior to 1995, this species was considered the same species as the saltmarsh sparrow (Ammodramus caudacutus), but is now separated based on differences in plumage, song, size, behaviour and genetics (3).

A somewhat small, plump bird, Nelson’s sharp-tailed sparrow has a large, flat head, a short tail and a conical-shaped bill. The face is orange, with a yellow-orange stripe above the eye and grey cheeks. The crown and back of the neck are grey, the throat is orange and the breast is buffy with slight streaking. The underparts are largely white, with faint dark lines, and sit in contrast to dark brown upperparts with light and dark streaking. The juvenile Nelson’s sharp-tailed sparrow is similar to the adult, but has buffier underparts, browner upperparts and a blackish crown (3) (4).

Nelson’s sharp-tailed sparrow breeds in three separate populations in North America: one in the northern plains of the U.S. and south-central Canada, one around southern Hudson Bay, and another in coastal parts of New England (5). All three populations spend winter along the Atlantic Coast, primarily between North Carolina and Florida, and along the Gulf Coast states to southern Texas (3).

The breeding habitat of Nelson’s sharp-tailed sparrow varies between the three main breeding populations. The inland population typically breeds in prairie wetlands where cordgrass (Spartina), sedges and common reeds (Phragmites) are abundant. Along Hudson Bay, this species breeds in sedge bogs above the high tide, where willow (Salix) and dwarf birch (Betula nana) grow. Iin New England, Nelson’s sharp-tailed sparrow breeds in farm fields, wet grasslands along large rivers and in tidal wetlands (3) (6).

During the winter, all three populations of Nelson’s sharp-tailed sparrow occupy brackish or tidal wetlands (3).

In the summer, Nelson’s sharp-tailed sparrow feeds mainly on insects and spiders, with some small crustaceans, snails and worms also eaten. At other times of the year, its diet consists almost entirely of vegetation and seeds. Usually, Nelson’s sharp-tail sparrow forages near the ground, probing in mud and picking up food items from the ground, foliage and water (3) (5) (7).

The breeding behaviour of Nelson’s sharp-tail sparrow has not yet been fully described, but it is thought that the male attracts a partner by singing in flight and from a perch. The male likely breeds with more than one female. The female constructs the nest alone, possibly with material collected by the male. In early June, 3 to 5 eggs are laid, which are then incubated by the female for around 11 days. The young fledge at around ten days, but are cared for by the female for two or three more weeks. The female may raise two broods in a single summer (3) (7).

Nelson’s sharp-tailed sparrow requires extensive mature, undisturbed marshland habitat in which to nest, and the loss of this habitat to agriculture is threatening this species across its range. In the upper Bay of Fundy, for example, it is estimated that as much as 80 percent of all salt marsh was converted to agricultural land by 1920 (3), while Nelson’s sharp-tailed sparrow habitat has been reduced by at least 50 percent in the Maritime Provinces of Canada (7). Drainage has also been a major cause of habitat loss along the St. Lawrence River. In addition, mowing, draining, ploughing, burning, and pesticide spraying can disrupt the Nelson’s sharp-tailed sparrow’s breeding cycle (3).

A conservation priority for Nelson’s sharp-tailed sparrow is the conservation of marshlands. In the past, management of this habitat has focused primarily on boosting populations of game species, with little consideration for other species. However, in recent years there has been a shift away from this focus, and species such as Nelson’s sharp-tailed sparrow are increasingly becoming the target of conservation efforts (3). Activities such as preventing the removal of vegetation through burning or harvesting and reducing the amount of open ground cover have benefited this species in particular (6).

Find out more about Nelson’s sharp-tailed sparrow:

• Cornell Lab of Ornithology: All About Birds - Nelson’s sharp-tailed sparrow:
  http://www.allaboutbirds.org/guide/Nelsons_Sparrow/id