Justification of Red List Category
This species appears to have undergone a rapid decline, which is suspected will continue into the future. Therefore, it has been uplisted to Vulnerable.
The population is estimated to be c.2,900,000 individuals (Rosenberg et al. 2016).
This species has undergone a large decline (88.8% decrease since 1966) measured by the Breeding Bird Survey; equating to a 33% decline over the period 2003-2015 (Sauer et al. 2016). Partners in Flight (Rosenberg et al. 2016) placed the decline between 1970 and 2014 at 85% (which would equate to a decline of 40.4% over 3 generations [12 years]), with a 'half-life' of 21 years (which would roughly equate to a decline of 32.7% over 3 generations). Therefore, the rate of decline is placed in the range 30-49% over 3 generations, and it is suspected that this will carry on into the future.
This species breeds in the Great Plains (north and central USA) and the Canadian Prairie Provinces (southern central Canada), and winters in south-central and south-western USA and north-central Mexico (Hill and Gould 1997). 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. Its decline measured by the Breeding Bird Survey equates to 3.3% per year over 2003-2015 or a 33% decline over the whole period. The BBS suggests a decline of 88.8% since 1966; and Partners in Flight estimate the decline as 85% between 1970 and 2014 (Rosenberg et al. 2016). Annual declines over the past decade (2005-2015) were most rapid in Alberta (7.5%), Manitoba (7.5%), and Wyoming (8.2%) (Sauer et al. 2016, D. P. Hill and L. K. Gould in litt. 2016).
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).
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). 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). 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 and there is a high level of predation by native predators (Hill and Gould 1997). 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 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).
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 under Canada's Species at Risk Act (SARA) (D. P. Hill and L. K. Gould in litt. 2016). A recovery strategy for the species has been proposed under the Species at Risk Act. The plan involves protecting remaining native grassland, reducing further habitat fragmentation from roads and possibly restoring native prairies from existing cropland (D. P. Hill and L. K. Gould in litt. 2016, Environment and Climate Change Canada 2016). It has been the focus of a number of studies on the breeding grounds, but no species-specific management actions are in place. It is included in multi-species studies taking place on the wintering grounds in Chihuahua, Mexico (G. Butcher in litt. 2016).
Text account compilers
Symes, A., Sharpe, C.J., Bird, J., Ashpole, J, Westrip, J., Harding, M.
Lebbin, D., Wells, J., Hill, D., Rosenberg, K., Gould, L., Butcher, G.
BirdLife International (2020) Species factsheet: Calcarius ornatus. Downloaded from http://www.birdlife.org on 28/05/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 28/05/2020.