White-tailed Ptarmigan (source: Wikipedia)
Ptarmigans are some of my favorite birds, and one of my proudest moments of birding was when I was leading some Mathcampers on a hike on Mt. Rainier: I was using my binoculars to try to find a lost camper but ended up spotting a well-camouflaged White-tailed Ptarmigan, Lagopus leucura (Galliformes: Phasianidae), instead!
Ptarmigans are species of alpine grouse that live in the Arctic boreal forest. They turn white in the winter and a mottled brown in the summer, generally dwell on the ground eating insects, and have very fluffy feet to aid in heat retention.
“White-tailed” should be fairly obvious, though the word “white” can be found throughout modern and ancient Germanic languages (hwit Old Frisian and Old Saxon, Gothic hweits, German weiss, etc), and “tail” comes from the Old Norse tagl “tail of a horse” (cf Gothic tagl meaning “hair”). The Oxford English Dictionary claims that white/hwit/hweits/etc is cognate with the Sanskrit sveta and Avestan spaeta, but even for me that’s a stretch.
“Ptarmigan” comes from the Scots-Gaelic tàrmachan, meaning “grouse,” a word that crops up in the name of the mountain Meall nan Tarmachan, next to Ben Lawers in the Scottish Highlands. (Meall by itself means “mound.”)
Lagopus is from the Greek λάγος (“lagos”) meaning “rabbit” and πους (“pous”) meaning “feet.” See what I said about them having furry feet?! Compare this to “octopus” (literally “eight-feet”), platypus (“flat-feet”), and, if you know your Greek plurals, words with the root “pod” meaning “foot,” such as “podiatrist.”
Finally, leucura means “white tail,” from the Greek λευκός (“leukos,” white, cf. leucocytes, leucistic, etc) and ουρά (“oura,” tail, a word that’s going to come up a lot in avian nomenclature).