Anser caerulescens x ANSER rossii
Status: Rare regular spring and fall migrant.
Taxonomy: Hybridization occurs between Snow Goose and Ross’s 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) and as a result of winter pair formation among individuals from different breeding colonies (Trauger et al 1971). Contrastingly, gene flow in white-cheeked geese may be much more restricted than it is in Snow Geese because pairing usually occurs on or near natal areas (Leaflour et al 2013).
Identification can be difficult due to variation in both parental species (Bird Hybrids: Index of Bird Hybrids).
Records: Despite the large overall number of records of this hybrid for North America in eBird (accessed Mar 2024), there are only 14 listed for Nebraska, although if observers searched the huge spring flocks of Snow and Ross’s Geese undoubtedly there would be more.
2 Jan 2022 Dawson Co
19-21 Feb 2022 Lincoln, Lancaster Co
29 Feb 2024 near Avoca, Cass Co
1-3 Mar 2013 Douglas Co
4 Mar 2023 Dixon Co
12 Mar 2011 Buffalo Co
19 Mar 2023 Saunders Co
20 Mar 2021 Scotts Bluff Co
28 Mar 2021 Seward Co
16 Apr 2022 Lakes North and Babcock, Platte Co
26 Apr 2013 Bazile Creek WMA, Knox Co
2 May 2022 Dakota Co
8 Nov 2021 Scotts Bluff Co
3 Dec 2021 (four) Scottsbluff WTP, Scotts Bluff Co
Comments: The fewest records are, surprisingly, from the Great Plains, although this might be an artifact of fewer observers there. Observers may not take time to search the huge flocks of Snow and Ross’s Geese passing through Nebraska during migrations.
At La Pérouse Bay, about 40 m east of Churchill, Manitoba on Hudson Bay, and other colonies, Ross’s Geese nest among Snow Geese, and mixed pairs and intermediates occur, and marked offspring from these mixed pairs have themselves produced offspring (Mowbray et al 2020).
Several informative photographs and discussion of this hybrid are on Bird Hybrids (Bird Hybrids: Index of Bird Hybrids).
Images
Literature Cited
Baldassarre, G. 2014. Ducks, geese, and swans of North America. Johns Hopkins University Press, Baltimore, Maryland, USA.
Johnsgard, P.A. 2014. What are Blue Ross’s Geese? NBR 82: 81-85.
Leafloor, J.O., J.A. Moore, and K.T. Scribner. 2013. A Hybrid Zone between Canada Geese (Branta canadensis) and Cackling Geese (B. hutchinsii). Auk 130: 487–500. https://doi.org/10.1525/auk.2013.12196.
Mowbray, T.B., F. Cooke, and B. Ganter (2020). Snow Goose (Anser caerulescens), version 1.0. In Birds of the World (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.snogoo.01.
Trauger, D.L., A. Dzubin, and J.P. Ryder. 1971. White geese intermediates between Ross’ Geese and Lesser Snow Geese. Auk 88: 856-875.
Recommended Citation
Silcock, W.R., and J.G. Jorgensen. 2024. Snow x Ross’s Goose (hybrid) (Anser caerulescens x rossii). In Birds of Nebraska — Online. www.BirdsofNebraska.org.
Updated 16 Mar 2024