Saltmarsh Sparrow

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Image:Saltmarshsparrow.JPG

Common Name: Saltmarsh Sparrow
Scientific Name: Ammodramus caudacutus

Size: 4.3-5.1 inches (11-13cm)

Habitat: North America; distributed along a narrow Atlantic coastal strip of the USA from Maine south to North Carolina, with a southward shift in winter as far as Florida and north to Maryland. Found in tidal coastal marshes where there is dense cordgrass, blackgrass or saltmeadow grass.

Status: Near Threatened. Global Population: 250,000 Mature individuals and decreasing. Localized populations have suffered throughout its range from the severe and ongoing loss, degradation and fragmentation of marshes owing to urban development. Further threats include chemical spills and other pollutants, invasive species (particularly Phragmites, which makes the habitat completely unsuitable) and sea level rise. The amount by which sea level will rise owing to climate change remains uncertain but Spartina patens dominated marsh (high marsh) may disappear or be greatly reduced in size as the large amount of development along the coast means that there is limited scope for marshes to migrate inland. To date the species has not been recorded nesting outside of high marsh habitats; the implications of sea-level rise and loss of high marsh habitats are therefore extremely serious.

A current project is attempting to develop population estimates for sites in Connecticut. Using survey data from throughout the species's range this project will estimate the total population size. Research into threats to the species, especially the impacts of climate change and sea-level rise is ongoing. The species occurs within a number of protected areas supporting coastal habitat.

Diet: Insects, spiders, marine invertebrates, and some seeds. They forage on the ground or in marsh vegetation, sometimes probing in mud.

Breeding: The Saltmarsh Sharp-tailed Sparrow is non-territorial and promiscuous, and only females provide parental care. Males occupy large overlapping home ranges, and the mating relationship features forced copulations by males.

An open cup nest of grass stems and blades, lined with finer grass blades and sometimes built up on sides to form partial covering is created. 2-6 Greenish, covered with dark speckles, eggs are laid.

Cool Facts: Breeding success in many Saltmarsh Sharp-tailed Sparrow populations seems limited by storms and especially spring (high) tides, which often flood nests. The most successful pairs in these populations are those that re-nest soon after the flood tides of the new moon.

The Saltmarsh Sharp-tailed Sparrow formerly was considered as the same species as the Nelson's Sharp-tailed Sparrow, collectively known as the Sharp-tailed Sparrow. The two forms have separate breeding ranges that barely overlap in Maine. They differ in genetics, songs, and subtle plumage characters.

In what sounds like a story out of the Maury Povich research labs, scientists in Connecticut have discovered that saltmarsh sparrows have the most promiscuous mating habits of all bird species.

The researchers discovered that 95 percent of females took a roll in the nest with more than one male during each nesting period. DNA analysis further revealed that bird siblings in the same batch frequently have different fathers with the average brood of chicks having 2.5 fathers.

Lead researcher Professor Chris Elphick commented on the study’s frisky findings, saying: “We were not surprised to find some level of promiscuity. But we were quite stunned at just how extreme the rate was.”


Found in Songbird ReMix Threatened, Endangered, Extinct 3

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