a skein of birds UK Subjectbird (birds)CategoryAnimals → BirdsConfidencehighAttestationwiktionary-attested 2 sourcesWiktionary - skeinWiktionary - Appendix:English collective nouns
a skein of ducks Context-dependent Subjectduck (ducks)CategoryAnimals → BirdsContextin flightConfidencehighAttestationwikipedia-cited 2 sourcesWikipedia - List of animal namesOxford University Press - AskOxford: D
a skein of geese Context-dependent Subjectgoose (geese)CategoryAnimals → BirdsContextin flightConfidencehighAttestationwikipedia-cited 4 sourcesWikipedia - List of animal namesOxford Dictionaries - What do you call a group of ...?U.S. Geological Survey Northern Prairie Wildlife Research Center - Common Questions: What Do You Call a Group of...?Oxford University Press - AskOxford: G