ROSS’S GOOSE

Anser rossii

Status: Abundant regular statewide spring migrant. Rare regular summer visitor central and east. Common regular fall migrant statewide. Rare regular winter visitor statewide.

Documentation:  Specimen: UNSM ZM11255, 6 Nov 1922 Hooper, Dodge Co (Tate 1966).

Taxonomy:  No subspecies recognized.

The genus Chen was recently lumped with genus Anser based on genetic studies (Chesser et al 2017).

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).

As with Snow Goose, two color morphs occur in Ross’s Goose. McLandress and McLandress (1979) first reported blue morph birds; 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 would be expected in increase, especially eastward, as Ross’s and blue morph Snow Geese increasingly come into contact in the breeding range (Johnsgard 2014). Putative hybrids are likely to result from matings of blue morph Snow Geese and Ross’s Geese, whether white or blue morph, as the blue plumage coloration is controlled by a dominant gene (Johnsgard 2014, Cooke and Cooch 1968).

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” Ross’s Geese, are under-reported. The lone hybrid report was of one in Kearney Co 7 Mar 2015. Reports of 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 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 (Jonsson et al 2013, 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.

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: 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., 5600 along I-80 in Lincoln Co 25 Mar 2001, and 2250 near North Platte 14 Mar 2012.

Summer: There were no summering records until 1998, when one summered in Clay Co in 1998 (Jorgensen 2012). Since then, there have been increasing numbers of stragglers in summer (May-Sep), usually involving birds unable to migrate due to injury.

Fall: Migration occurs over an extended period, reflecting movements of Snow Geese, generally from mid-Oct through early Jan, peaking in early to mid-Nov.

  • High counts: 400 in Fillmore Co 27 Nov 2015, 232 in Keith Co 17 Nov 2017, 88 at North Platte NWR, Scotts Bluff Co 9 Nov 1997, and 79 at Lake McConaughy, Keith Co 31 Oct 2006.

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 records have increased, sightings are still usually of singles or small groups; large winter flocks have not been reported.

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
NWR: National Wildlife Refuge
UNSM: University of Nebraska State Museum
WPA: Waterfowl Production Area (Federal)

Acknowledgement

Photograph (top) of Ross’s Geese (front, center) with Snow Geese  in central Nebraska 7 March 2008 by Phil Swanson.

Literature Cited

Baldassarre, G. 2014. Ducks, geese, and swans of North America. Johns Hopkins University Press, Baltimore, Maryland, USA.

Cooke, F., and G. Cooch. 1968. The genetics of polymorphism in the Goose Anser caerulescens. Evolution 22: 289-300.

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. 2013. Ross’s Goose (Anser rossii), version 2.0. In The Birds of North America (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, New York, USA. https://doi.org/10.2173/bna.162

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.

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.  2017.  Ross’s Goose (Anser rossii), Version 1.0. In Birds of Nebraska — Online. www.BirdsofNebraska.org


Birds of Nebraska – Online