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Passerculus henslowii 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Passerellidae

Scientific Name: Passerculus henslowii
Species Authority: (Audubon, 1829)
Common Name(s):
English Henslow's Sparrow
Synonym(s):
Ammodramus henslowii (Audubon, 1829)
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.

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Rosenberg, K., Wells, J. & Holimon, B.
Facilitator/Compiler(s): Harding, M., Isherwood, I., Khwaja, N., Wege, D., Westrip, J.
Justification:
This species has declined significantly over the last three decades owing to the loss and degradation of its grassland habitats. Although recent population trends are unclear, it is precautionarily listed as Near Threatened as a result of suspected moderately rapid population declines. Nevertheless, further information on the apparently positive trends observed since the establishment of the Conservation Reserve Programme may in due course lead to its reclassification as Least Concern, assuming those grasslands are not converted to agriculture due to commodity prices.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Ammodramus henslowii breeds in the eastern U.S.A., from Minnesota (primarily in the south-east) east to southern Ontario and New York, and extending south-west to north-east Oklahoma, and south-east to north-western Kentucky and West Virginia. Isolated breeding populations also exist in north-east Virginia and north-east North Carolina. It is extirpated or a rare breeder in the north-east U.S. states, from Vermont south to Delaware. It winters in coastal states from south-east North Carolina south to Florida (except for the southern tip) and west to eastern Texas (AOU 1983, Sibley and Monroe 1990). It was once common in unploughed, periodically burnt tall-grass prairie, which originally stretched from Illinois west to Kansas and Nebraska (Rising 1996), but these populations have declined over the last three decades, with the greatest declines being in the northern and eastern portions of the range (AOU 1983). Southern populations, however, have tended to increase (Rising 1996), apparently in association with the creation of undisturbed grassland habitat by the Conservation Reserve Program, and the current population is estimated to be 79,000 individuals (Rich et al. 2003).

Countries occurrence:
Native:
Canada; United States
Additional data:
Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:1500000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Rich et al. (2003).



Trend Justification:  This species has undergone a large and statistically significant decrease over the last 40 years in North America (-96.3% decline over 40 years, equating to a -56.1% decline per decade; data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007). However, analysis by the US Fish and Wildlife Service indicated that the population has now stabilised and may even have begun to increase. Therefore, recent declines are estimated to fall within the band 20-30%.
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:During the breeding season, the species is typically found in grassland with tall and dense grass, dead trees and thick leaf-litter, although site choice is unpredictable from year to year (Dornak et al. 2013). On their wintering grounds, though, birds prefer recently burned areas (Bechtoldt and Stouffer 2005), with low densities of litter and near-ground vegetation (Carrie et al. 2002, Holimon et al. 2008). Optimal fire intervals may vary regionally, possibly due to different rates of litter accumulation in mesic and drier upland savannas (Palaz et al. 2010). They are often associated with longleaf pine Pinus palustris savanna at this time (Plentovich 1999, Bechtoldt and Stouffer 2005, Thatcher et al. 2006), but also occur in saline soil barrens (Holimon et al. 2004, Holimon et al. 2008). Mowed fields are generally avoided, as are fields with a lot of woody vegetation (Rising 1996, Holimon et al. 2008).

Systems:Terrestrial; Freshwater
Continuing decline in area, extent and/or quality of habitat:Unknown
Generation Length (years):3.9
Movement patterns:Full Migrant

Threats [top]

Major Threat(s): Wetland draining and destruction of grassland habitat through fire suppression, conversion to agriculture or pine plantations and earlier and more frequent cutting of hayfields (Rising 1996, Federal Register 1998, Pruitt 1996, Cooper 2012) all represent threats, and in combination they have caused population declines. The continued investment in fire suppression programmes could result in reduced funding for prescribed fire in longleaf pine savannas and therefore loss of suitable wintering habitat for this species (United States Department of Agriculture 2015). Further, significant, additional U.S. Department of Agriculture’s (USDA) Conservation Reserve Program grasslands are predicted to be converted to agricultural fields if the high price of corn continues, resulting in loss of breeding habitat (Cooper 2012, Lark et al. 2015). This species has been reported to suffer mortality as a result of collisions with communications towers (Longcore et al. 2013).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
The species is monitored within the North American Breeding Bird Survey and Christmas Bird Count. It is listed as an Endangered species in Canada, and within its U.S. breeding range is considered Endangered in seven states, Threatened in five, and of Special Concern in four. Some grassland conservation activities will be undertaken as part of the national Partners in Flight bird conservation efforts. The Conservation Reserves Programme, while not specifically intended to benefit this species, has provided a large area of undisturbed grassland habitat, and Henslow's Sparrow has colonised these fields in many areas. Creation of large areas of undisturbed grasslands through this programme appears to have contributed to recent reversal of long-term population declines (Cooper 2012). It is on the watch list as part of the State of North America's Birds (North American Bird Conservation Initiative 2016).

Conservation Actions Proposed
Continue to monitor population trends and determine its responses to grassland management regimes. Maintain or increase levels of prescribed fire and other management activities needed for suitable breeding and wintering habitat (Cooper 2012).  Combine USDA farmbill program funding and landowner incentives from other sources to help maintain or develop grasslands on privately owned lands that would otherwise be utilised as agricultural fields (Cooper 2012).


Citation: BirdLife International. 2016. Passerculus henslowii. The IUCN Red List of Threatened Species 2016: e.T22721138A94700280. . Downloaded on 11 December 2016.
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