Nelson’s Sparrow

Like the closely related Saltmarsh Sparrow, Nelson’s Sparrow is one of a handful of songbirds adapted to life in coastal salt marshes. Here in the Northeast, the two species co-occur from southern Maine to northern Massachusetts, and even hybridize in part of the overlap zone. This can make telling them apart challenging at times, since there are individuals with intermediate characteristics. In New Hampshire, Saltmarsh Sparrows outnumber Nelson’s by at least 3:1. Most of the latter are found in the marshes around Great Bay rather than along the immediate coast, although a few nest in smaller marshes from North Hampton to Rye.

Nelson’s Sparrows are the only species in coastal marshes from central Maine through Maritime Canada and along the lower reaches of the St. Lawrence River in Quebec. In parts of this region they also use wet fields and freshwater habitats. These latter habitats converge with those used by a completely distinct subspecies of Nelson’s Sparrow on the Great Plains, where most of the species’ global population occurs. These “inland” Nelson’s are brighter than the “Acadian” ones in the Northeast and are sometimes recorded as migrants in New Hampshire, primarily in the fall.

Like the Saltmarsh Sparrow, male Nelson’s Sparrows are not territorial, do not form pair bonds, and play no role in caring for young – the latter is left solely to the females. Nest losses to tidal flooding are a significant threat to the species, but perhaps less so than for Saltmarsh Sparrows. In New Hampshire this is partially because marshes around Great Bay show less dramatic fluctuations than those along the coast. These same marshes are also a little less threatened by sea level rise. Nelson’s Sparrows that use grassland and freshwater habitats elsewhere in their range are even more secure, although wetland loss to drought and agriculture in the Great Plains remains a threat.