BirdLife Species factsheet for Saltmarsh Sparrow: http://datazone.birdlife.org/species/factsheet/saltmarsh-sparrow-ammospiza-caudacuta
Saltmarsh Sparrow, Ammospiza caudacuta (formerly Ammodramus caudacutus), is endemic to the Atlantic coast of U.S.A. During the breeding season it is generally found from Maine south to the Delmarva Peninsula, but shifts its range southwards during the winter, and may occur as far south as Florida (Greenlaw and Woolfenden 2007, J. S. Greenlaw in litt. 2012). It inhabits areas of tidal coastal marshes with dense grasses such as blackgrass, cordgrass and saltmeadow grass. It has been proposed that this species occupies only a small area of this habitat (<2,000km2) (P. Comins in litt. 2003, C. Elphick in litt. 2003), and ongoing threats mean that the species is currently listed as Vulnerable under criterion B2ab(i,ii,iii,iv,v) (see BirdLife International 2017).
The most important threat to this species and its habitat has been urban development leading to the loss, degradation and fragmentation of marshes (Greenlaw and Rising 1994, Sibley 1996, C. Elphick in litt. 2003, 2012). Additionally, its habitat has suffered degradation as a result of pollution (e.g. from chemical spills) and invasive species such as Phragmites which make the habitat unsuitable for this species (C. Elphick in litt. 2012). Another important threat, which the species is likely to suffer from even more into the future, is climate change leading to sea-level rises (C. Elphick in litt. 2003, 2012). It is uncertain how much sea-levels will rise within this species’s range, but it is likely that the marshes this species prefers may disappear or be substantially reduced in size (minimum projections of 40-75% lost [C. Elphick in litt. 2012]), as development and habitats/species more resistant to flooding may be preventing the inland migration of tidal marshes (Field et al. 2016, C. Elphick in litt. 2003). However, even given these threats the species probably should not warrant listing as Vulnerable under criterion B2, because it does not meet condition (a) severely fragmented or ≤10 locations. It had been considered to be severely fragmented, but genetics work and the fact it may make seasonal movements mean that there may be some connectivity between areas (albeit potentially limited) (A. Kovach and C. Elphick in litt. 2016).
More up to date population estimates suggest that the species may number 53,000 (37,000-69,000) individuals in the breeding range (Wiest et al. 2016), which would roughly equate to 35,333 (24,667-46,000) mature individuals. Therefore, the species would also not approach the threshold for Vulnerable based on population size. Population trend estimates, however, do imply that the species does warrant remaining as threatened, and indeed would warrant uplisting from Vulnerable to Endangered. Work by Correll et al. (2017) has given an estimated 9.0% annual decline in this species since the 1990s. This equates to a 65.9% decline over 3 generations (11.4 years), and meets the threshold for Endangered. Given that climate change is thought to be able to continue (or increase) these declines into the future it is proposed that this species be listed as Endangered under criteria A2ace+3ce+4ace.
We welcome any comments or further information regarding this proposed uplisting.
BirdLife International. 2017. Species factsheet: Ammospiza caudacuta. Downloaded from http://www.birdlife.org on 10/04/2017.
Correll, M. D.; Wiest, W. A.; Hodgman, T. P.; Shriver, W. G.; Elphick, C. S.; McGill, B. J.; O’Brien, K. M.; Olsen, B. J. 2017. Predictors of specialist avifaunal decline in coastal marshes. Conserv. Biol. 31: 172-182.
Field, C. R.; Gjerdrum, C.; Elphick, C. S. 2016. Forest resistance to sea-level rise prevents landwards migration of tidal marsh. Biol. Conserv. 201: 363-369.
Greenlaw, J. S.; Rising, J. D. 1994. Sharp-tailed Sparrow (Ammodramus caudacutus). In: Poole, A.; Gill, F. (ed.), The birds of North America, No. 112, pp. 1-28. The Academy of Natural Sciences, Philadelphia and The American Ornithologists’ Union, Philadelphia and Washington, D.C.
Greenlaw, J. S.; Woolfenden, G. E. 2007. Wintering distributions and migration of Saltmarsh and Nelson’s Sharp-tailed Sparrows. Wilson Journal of Ornithology 119(3): 361-377.
Sibley, D. 1996. Field identification of the Sharp-tailed Sparrow complex. Birding 28: 197-208.
Wiest, W. A.; Correll, M. D.; Olsen, B. J.; Elphick, C. S.; Hodgman, T. P.; Curson, D. R.; Shriver, W. G. 2016. Population estimates for tidal marsh birds of high conservation concern in northeastern USA from a design-based survey. Condor 118: 274-288.