Justification of Red List Category
This species appears to have undergone a rapid decline, which is suspected to continue into the future. Therefore, it is listed as Vulnerable.
Partners in Flight (2019) currently estimate the population to number 3.1 million mature individuals.
This species has undergone a large decline, measured at ~85% between 1970 and 2014 by Partners in Flight (Rosenberg et al. 2016), whom currently estimate the species to be declining at a rate of 4.38% per year, or 36.1% across a ten year period (Partners in Flight 2019). The Breeding Bird Survey also note a ~88.8% decrease since 1966 (Sauer et al. 2016) and estimate current annual declines of ~3.22% between 2010-2017 (Pardieck et al. 2018). Whilst only equable to a 27.9% decline across a ten year period, the Christmas Bird Count however suggest that the rate of decline may be higher (Meehan et al. 2018) and as such, in agreement with the Partners in Flight (2019) estimate, the rate of population decline is placed in the band, 30-49%. Declines are most pronounced in Canada where the species is estimated to have declined by more than 95% between 1970-2017, with short-term population declines reaching 52.9% per decade between 2007-2017 at rate of ~7.2% per year, peaking in Alberta at ~11.8% per year (COSEWIC 2019, Smith et al. 2019).
This species breeds in the Great Plains (north and central U.S.A.) and the Canadian Prairie Provinces (southern central Canada), and winters in south-central and south-western U.S.A. and north-central Mexico (Hill and Gould 1997, Ellison et al. 2017); it typically migrates along the central flyway to the east of breeding sites, circumventing high elevation terrain (Ellison et al. 2017). It has undergone long-term population declines so that it is now rare or extirpated as a breeding species in a number of States formerly occupied.
It is a native-prairie specialist (Anstey et al. 1995), its breeding range restricted to short-grass and mixed-grass prairie regions, and its wintering range restricted to dry grasslands and deserts, where it feeds on grains in high density flocks (Hill and Gould 1997). It prefers native grasslands recently disturbed by fire, grazing or mowing, and will avoid nesting in areas protected from grazing or cultivated fields (Maher 1973, Owens and Myres 1973). Critical habitat has been identified as open areas of upland native grassland > 39 ha in fair to excellent range condition with flat to gently rolling topography and with limited woody vegetation or invasion by exotic grasses (Environment and Climate Change Canada 2018, COSEWIC 2019, D. Hill in litt. 2020).
As a result of conversion of native prairie to croplands and urban developments it has disappeared from much of its historical breeding range (e.g. in Kansas, Nebraska and Minnesota); the species exhibits significantly lower nest survival and fledges fewer young in non-native grassland pastures compared to native prairies (Lloyd and Martin 2005, Davis et al. 2016). Fragmentation of native grasslands reduces the suitability of breeding habitat (D. P. Hill and L. K. Gould in litt. 2016); a study in southern Saskatchewan found that the species did not use habitat patches <39 ha (Davis 2004). Abundance, and nest fledging, success and productivity are reduced along roads (Sutter et al. 2000) and in close proximity to oil and gas wells (Ng 2017, Yoo and Koper 2017, Ng 2019, PCAP 2019). It exhibits delayed displacement (>300 m) in response to wind energy infrastructure (Shaffer and Buhl 2015). Conversion of the species's wintering habitat to irrigated agriculture in Mexico also poses a threat (G. Butcher in litt. 2016). Recent conversion of grasslands to cropland in the Valles Centrales (the largest known wintering population of c.250,000 individuals) of Chihuahua, Mexico, is estimated to have displaced more than 130,000 wintering individuals (Pool et al. 2014). The wintering range has also contracted: this is presumed to have resulted from a population decline. Brown-headed cowbirds parasitise this species at low to moderate rates and there is a high level of predation by native predators (Hill and Gould 1997, Shaffer et al. 2019). It can be vulnerable to disturbance (Hill and Gould 1997), and it has been reported killed at communication towers (Longcore et al. 2013). The species is also thought vulnerable to predicted drying as a result of climate change in the western part of its breeding range and in the wintering range (G. Butcher in litt. 2016), although Wilson et al. (2018) modelled data suggested that the species's range size illustrates no significant response to changing drought conditions.
Conservation Actions Underway
The species is included on the 'Watch List' of the State of North America's Birds as a species of high conservation concern (NABCI 2016). It was listed as Threatened in Canada in 2009 (Committee on the Status of Wildlife in Canada 2009) and was listed under Schedule 1 of Canada's Species at Risk Act (SARA) in 2012 (Environment and Climate Change Canada 2018). A recovery strategy for the species has been proposed under the Species at Risk Act (Environment and Climate Change Canada 2018). The plan involves protecting remaining native grassland, reducing further habitat fragmentation from roads and possibly restoring native prairies from existing cropland (Environment and Climate Change Canada 2018). It has been the focus of a number of studies on the breeding grounds, but no species-specific management actions are in place. A multi-species action has been completed in southwestern Saskatchewan (Environment and Climate Change Canada 2016) and will be amended to include chestnut-collared longspur (Environment and Climate Change Canada. 2018). It is included in multi-species studies taking place on the wintering grounds in Chihuahua, Mexico (G. Butcher in litt. 2016).
Text account compilers
Ashpole, J, Bird, J., Butcher, G., Gould, L., Harding, M., Hill, D., Lebbin, D., Rosenberg, K., Sharpe, C.J., Symes, A., Wells, J. & Westrip, J.R.S.
BirdLife International (2022) Species factsheet: Calcarius ornatus. Downloaded from http://www.birdlife.org on 28/11/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 28/11/2022.