The staining should be completely environmentally determined and not related to differences in species or species behavior. So, it should not be a reliable way to differentiate the swan species. Better ways to differentiate the species beside field marks include calls and flock size. Both species are quite vocal and Sibley mobile eBird guide plays vocalizations and will be right there when needed to compare calls. Trumpeters move about in family groups typically of 2 to 8 birds. Tudras migrate in flocks of 20 to 100. So if you see a smattering of small groups of swans, they are probably Trumpeters and if you see a flock of 20 or more, they are probably Tudras. You can still see several family groups of Trumpeters together or when out of peak migration a small group of 10 to 20 Tundras.
Steve Weston On Quigley Lake in Eagan, MN swest...@comcast.net On Wed, Apr 21, 2021 at 12:44 AM Keith Carlson <keitheca...@gmail.com> wrote: > Can anybody tell me if coral or pinkish brown staining of the head is a > reliable way to distinguish tundra swans from trumpeter swans. Saw quite a > few with those colored heads on the wildlife drive at the Sherburne > National Wildlife Refuge last Saturday and I was guessing they were tundra > but was uncertain. They weren't very vocal so that didn't help. > > ---- > Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net > Archives: http://lists.umn.edu/archives/mou-net.html > > During the pandemic, the MOU encourages you to stay safe, practice social > distancing, and continue to bird responsibly. > ---- Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net Archives: http://lists.umn.edu/archives/mou-net.html During the pandemic, the MOU encourages you to stay safe, practice social distancing, and continue to bird responsibly.
