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Ammospiza caudacuta 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Passerellidae

Scientific Name: Ammospiza caudacuta (Gmelin, 1788)
Common Name(s):
English Saltmarsh Sparrow, Saltmarsh Sharp-tailed Sparrow
Synonym(s):
Ammodramus caudacutus (Gmelin, 1788)
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
Taxonomic Notes:

Ammospiza caudacuta (del Hoyo and Collar 2016) was previously placed in the genus Ammodramus and listed as A. caudacutus following AOU (1998 & supplements).

 

Identification information: 13.5 cm. Well-marked and long-billed sparrow. Colourful orange, black and grey head pattern, grey crown and nape, and white streaks on back. Similar spp. Told from close relative Nelson's Sparrow A. nelsoni by its orange malar (brighter than breast), poorly defined white belly and the distinct black streaking on the breast and flanks. Voice Much softer song than A. nelsoni lacking distinctive final note of that species.

Assessment Information [top]

Red List Category & Criteria: Endangered A2ace+3ce+4ace ver 3.1
Year Published: 2017
Date Assessed: 2017-10-01
Assessor(s): BirdLife International
Reviewer(s): Symes, A.
Contributor(s): Butcher, G., Comins, P., Elphick, C., Greenlaw, J., Kovach, K., O'Brien, K., Olsen, B., Rosenberg, K., Shriver, G. & Wells, J.
Facilitator/Compiler(s): Benstead, P., Bird, J., Butchart, S., O'Brien, A., Sharpe, C.J., Wege, D., Khwaja, N., Symes, A., Westrip, J.
Justification:
This species occupies only a small and fragmented range, and new analyses have shown that it is declining at a rapid rate. It has therefore been uplisted to Endangered.
Previously published Red List assessments:

Geographic Range [top]

Range Description:Ammodramus caudacutus is confined to a narrow Atlantic coastal strip of the U.S.A. from Maine southwards to the Delmarva Peninsula, with a southward shift in winter as far as Florida and north to Maryland and Massachusetts (Greenlaw and Woolfenden 2007, J. S. Greenlaw in litt. 2012). It is common to abundant in saltmarshes in the core of its range (J. S. Greenlaw in litt. 2012) and has been estimated to number c.250,000 individuals (Rich et al. 2003, P. Comins in litt. 2003); more recent estimates from suggest that the species may number 53,000 (37,000-69,000) individuals in the breeding range (Wiest et al. 2016). Its highly fragmented range is c.20,000 km2, within which it occupies an area of less than 2,000 km2 of appropriate habitat (P. Comins in litt. 2003, C. Elphick in litt. 2003).

Countries occurrence:
Native:
United States
Vagrant:
Canada
Additional data:
Estimated area of occupancy (AOO) - km2:1999Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:241000
Continuing decline in extent of occurrence (EOO):YesExtreme fluctuations in extent of occurrence (EOO):No
Continuing decline in number of locations:Yes
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Recent population estimates suggest that the species may number 53,000 (37,000-69,000) individuals in the breeding range (Wiest et al. 2016). This population estimate was conducted to largely capture the breeding population (C. Elphick in litt. 2017) and so this may actually equate to the number of mature individuals. The sex ratio in this species is approximately 60:40 male:female, and so the number of breeding individuals could have been as low as c.29,600 mature individuals. Therefore, the population size is placed in a range from 29,500-69,000 mature individuals.



Trend Justification:  Correll et al. (2017) estimated that the species has undergone a 9.0% annual decline throughout its range since the 1990s. This equates to a 65.9% decline over 3 generations (11.4 years) (placed here in the range 50-79%), which is considered likely to continue into the future.
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:29500-69000Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:Yes
No. of subpopulations:2-100Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No
No. of individuals in largest subpopulation:1-89

Habitat and Ecology [top]

Habitat and Ecology:Ammodramus caudacutus is found in tidal coastal marshes where there is dense cordgrass, blackgrass or saltmeadow grass. Home ranges preferentially include Spartina patens and Juncus gerardii cover (Shriver et al. 2010), and nesting success is positively correlated with the presence of the latter (Gjerdrum et al. 2008). Nesting takes place from mid May through to early August and males sing occasionally (C. Elphick in litt. 2012) during this time. Nests are placed 6-15 cm above the ground and usually 3-5 greenish white to greenish blue eggs, speckled with reddish brown, are laid. They are not territorial and are not usually found in mixed species flocks (Rising 1996), apart from with other tidal marsh sparrows during non-breeding periods (J. S. Greenlaw in litt. 2012, C. Elphick in litt. 2016).

Systems:Terrestrial
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):3.8
Movement patterns:Full Migrant

Threats [top]

Major Threat(s): Localised populations have suffered throughout its range from the historical loss and fragmentation of marshes owing to urban development (Greenlaw and Rising 1994, Sibley 1996, C. Elphick in litt. 2003, 2012). Recent population declines are associated with the presence and number of downstream tidal restrictions (levees, roads, train tracks, etc.) that alter natural flow of tide waters in and out of marshes, although the mechanism behind this link is not well known (Correll et al. 2017). Further on-going threats include increased tidal flooding (e.g., due to sea level rise and increased storm surge frequency/magnitude), hybridization with Nelson’s Sparrows A. nelsoni (which may reduce fitness and limit the number of pure Saltmarsh Sparrow populations), degradation from chemical spills and other pollutants, and invasive species (particularly Phragmites, which makes the habitat completely unsuitable) (C. Elphick in litt. 2016). 
This species appears to be extremely vulnerable to a slight rise in sea-level, as nests are lost due to flooding (Bayard and Elphick 2011, Shriver et al. 2016, Field et al. 2017a). 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, with the potential for the species to go extinct in the near future (see Field et al. 2017a). 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; and vegetation within marshes is already changing in a manner that suggests marshes are getting wetter (Field et al. 2016).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
The Saltmarsh Habitat and Avian Research Program (SHARP) and their partners have conducted a number of recent studies to assess the species’ status.  These include a range-wide population survey (Wiest et al. 2016) and trend assessment (Correll et al. 2017), demographic studies (e.g. Field et al. 2017a,b), studies of changing habitat conditions (Field et al. 2016), as well as studies on many other aspects of the species’ biology. The species occurs within a number of protected areas supporting coastal habitat, and restoration of tidal marshes is on-going (C. Elphick in litt. 2012). Past efforts to restore tidal flow to marshes appear not to have benefitted saltmarsh sparrow (Elphick et al. 2015). Over the past few years, saltmarsh sparrows have become more central to coastal marsh planning within the species’ range and SHARP has begun investigating the effects of coastal management activities on the species (C. Elphick et al. in litt. 2016). This work includes investigations of potential methods to increase habitat area (including facilitation of marsh migration into upland habitats and creation of floating habitat structures) and systematic evaluation of a range of marsh management activities throughout the species’ range.

Conservation Actions Proposed
Protect high-elevation marsh suitable for flooding (C. Elphick in litt. 2016). Manage areas to reduce nest flooding on extreme high tides, and facilitate marsh migration at the upland edges of marshes (C. Elphick in litt. 2016).

Citation: BirdLife International. 2017. Ammospiza caudacuta. The IUCN Red List of Threatened Species 2017: e.T22721129A119141790. . Downloaded on 12 December 2017.
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