Anser rossii
Status: Abundant regular spring migrant statewide. Rare regular summer visitor central and east. Common regular fall migrant statewide. Rare regular winter visitor west, south, and east.
Documentation: Specimen: UNSM ZM11255, 6 Nov 1922 Hooper, Dodge Co (Tate 1966).
Taxonomy: The genus Chen was recently lumped with genus Anser based on genetic studies (Chesser et al 2017).
No subspecies are recognized (Gill et al 2022).
Hybridization occurs between Ross’s Goose and Snow Goose, estimated at 4.7% of a sample of around 12,000 Ross’s and Snow Geese in the Central Flyway examined between 1961 and 1968 (Trauger et al 1971, Baldassare 2014). This percentage will likely increase as Ross’s Goose expands its breeding range eastward (Trauger et al 1971, Johnsgard 2014). For discussion of Nebraska records of hybrids with Snow Goose, see Snow x Ross’s Goose (hybrid). Ross’s Goose also hybridizes with Cackling and Canada Geese; for Nebraska records of these hybrids see Ross’s x Cackling Goose (hybrid), and Ross’s Goose x Canada Goose (hybrid).
As with Snow Goose, two color morphs occur in Ross’s Goose, although the “pure” blue Ross’s Goose is thought to have been derived from hybridization of Ross’s Goose with blue morph Snow Goose and subsequent backcrosses influenced by introgression of the dominant “blue gene” from Snow Goose (Cooke and Cooch 1968); there is no evidence for existence of a “blue gene” in Ross’s Goose (Weckstein et al 2002, Jonsson et al 2020). Apparent field-identifiable hybrid blue Ross’s geese are presumably F1 or F2 hybrids resulting from matings of blue morph Snow Geese and white or blue morph Ross’s Geese. McLandress and McLandress (1979) first reported apparent blue morph Ross’s Geese; they found three among 38,825 Ross’s Geese in California. As well as these three “pure” blue morph Ross’s Geese, McLandress and McLandress (1979) found putative hybrid blue morph birds that possessed characters intermediate between Ross’s Goose and Snow Goose. Numbers of both “pure” and hybrid blue morph Ross’s Geese are expected in increase, especially eastward, as Ross’s and blue morph Snow Geese increasingly come into contact in the breeding range (Johnsgard 2014).
There are eight Nebraska reports of blue morph Ross’s Geese involving at least 12 birds, but only one of a blue morph hybrid. This suggests that hybrids, which might be expected to be more common than “pure” blue morph Ross’s Geese, are under-reported. The lone hybrid report was of one in Kearney Co 7 Mar 2015. Reports of apparent blue morph Ross’s Geese are in late winter, 26 Feb-21 Mar: one was in Stanton Co 26 Feb 1998, one was photographed at Harvard WPA, Clay Co 26 Feb 2007, one was photographed by Kwnt Skaggs near Kearney 5 Mar 2009 (Brogie 2009), one was photographed in central Nebraska 17 Mar 2017, three were in a pure flock of 50+ Ross’s Geese in Hall Co 18 Mar 2000, a single bird was near Pierce, Pierce Co 19 Mar 1994 (Gubanyi 1996), and “a few” were in a Ross’s Goose flock at Cochran Lake, Scotts Bluff Co, 21 Mar 2001.
Changes since 2000: This species has increased from a population of only 5000-6000 as recently as the 1930s to more than 1.1 million in 2005 and >2 million in 2007 (Jonsson et al 2020, Baldassare 2014). Nebraska occurrence has reflected this increase, with increasing numbers observed. Temporal occurrence is now similar to Snow Goose, including increasing winter and summer records.
Spring: This species usually occurs with Snow Geese. Spring arrival and departure occurs between early Feb and late Apr, peaking in early Mar. See Summer for records after early Mar.
Johnsgard (2012) estimated that some 2% of white geese migrating through Nebraska are Ross’s Geese; since the mid-continent flock of Snow Geese numbers some 4.9 million, Johnsgard (2012) estimated that some 90,000 Ross’s Geese pass through Nebraska. More recent estimates indicate the number of Snow Geese in the mid-continent may be 2-4 times greater than 4.9 million (Mark Vrtiska, NGPC, personal communication). Thus, the estimated number of Ross’s Geese migrating through Nebraska would be proportionally higher as well.
- High counts: 170,000 at Sutherland Reservoir, Lincoln Co 2 Mar 2023, 50,000 in Hall Co 13 Mar 2018, 30,000 over Harlan Co 20 Feb 2018, and 21,920 over Nuckolls Co 4 Feb 2017.
Summer: There were no summering records until 1998, when one summered in Clay Co (Jorgensen 2012). Since then, there have been increasing numbers of stragglers in summer (May-Sep), usually involving birds unable to migrate due to injury. There are no Panhandle summer records; latest dates there are 11 May 2003 and 22 May 2022.
Fall: Migration occurs over an extended period, reflecting movements of Snow Geese, generally occurring from mid-Oct through early Jan and peaking in early to mid-Nov.
- High counts: 3100 over Nuckolls Co 25 Nov 2020, 3000 at Lake McConaughy, Keith Co 7 Dec 2022, 750 in Scotts Bluff Co 8 Nov 2021, 500 at Cochran Lake, Scotts Bluff Co 8 Nov 2022, and 500 at Lake Minatare, Scotts Bluff Co 10 Nov 2023.
Winter: The increase in number of winter stragglers has been marked since the first record of three in Kearney Co with four Snow Geese 22 Jan 1995. Although mid-winter (Jan 10-20) records have increased, sightings are still usually of singles or small groups; large winter flocks had not been reported until 400 were estimated with a large flock of Snow Geese 18 Jan 2020.
Comments: Huntley (1971) and Tate (1966) published information on a mounted specimen (cited above) taken by a hunter near Hooper, Dodge Co on or before 6 Nov 1922, the first Nebraska record. However, Ross’s Goose has been reported regularly in Nebraska only since about 1970.
Abbreviations
NGPC: Nebraska Game and Parks Commission
UNSM: University of Nebraska State Museum
WPA: Waterfowl Production Area (Federal)
Acknowledgement
Photograph by Phil Swanson (top) of Ross’s Geese (front, center) with Snow Geese in central Nebraska 7 March 2008.
Literature Cited
Baldassarre, G. 2014. Ducks, geese, and swans of North America. Johns Hopkins University Press, Baltimore, Maryland, USA.
Brogie, M.A. 2009. 2009 (21st) Report of the NOU Records Committee. NBR 77: 160-168.
Chesser, R.T., K.J. Burns, C. Cicero, J.L. Dunn, A.W. Kratter, I.J. Lovette, P.C. Rasmussen, J. V. Remsen, Jr., J.D. Rising, D.F. Stotz, and K. Winker. 2017. Fifty-eighth supplement to the American Ornithological Society’s Check-list of North American Birds. Auk 134: 751-773.
Cooke, F., and G. Cooch. 1968. The genetics of polymorphism in the Goose Anser caerulescens. Evolution 22: 289-300.
Gill, F., D. Donsker, and P. Rasmussen (Eds). 2022. IOC World Bird List (v 12.2). Doi 10.14344/IOC.ML.12.2. http://www.worldbirdnames.org/.
Gubanyi, J.G. 1996. 1995 (Seventh) Report of the NOU Records Committee. NBR 64: 132-138.
Huntley, C.W. 1971. Ross’ Geese. NBR 39: 37.
Johnsgard, P.A. 2012. Wings over the great plains: the central flyway. Zea E-Books. 13. University of Nebraska Digital Commons. Lincoln, Nebraska, USA.
Johnsgard, P.A. 2014. What are Blue Ross’s Geese? NBR 82: 81-85.
Jónsson, J.E., J.P. Ryder, and R.T. Alisauskas. 2020. Ross’s Goose (Anser rossii), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.rosgoo.01
Jorgensen, J.G. 2012. Birds of the Rainwater Basin, Nebraska. Nebraska Game and Parks Commission, Lincoln, Nebraska, USA.
McLandress, M.R., and I. McLandress. 1979. Blue-phase Ross’ Geese and other blue-phase geese in western North America. Auk 96: 544-550.
Tate, J., Jr. 1966. An early record of the Ross’ Goose in Nebraska. NBR 34: 46-47.
Trauger, D.L., A. Dzubin, and J.P. Ryder. 1971. White geese intermediates between Ross’ Geese and Lesser Snow Geese. Auk 88: 856-875.
Weckstein, J.D., A.D. Afton, R.M. Zink, and R.T. Alisauskas. 2002. Hybridization and population subdivision within and between Ross’s Geese and Lesser Snow Geese: a molecular perspective. Condor 104: 432–436.
Acknowledgement
Mark P. Vrtiska provided access to harvest data and numerous helpful comments that improved this species account.
Recommended Citation
Silcock, W.R., and J.G. Jorgensen. 2023. Ross’s Goose (Anser rossii). In Birds of Nebraska — Online. www.BirdsofNebraska.org
Birds of Nebraska – Online
Updated 20 Dec 2023