The Swiss cuckoo crock, as correctly termed originates from a rather remarkable duality of unusual occurrences.
Cuckoos suffer from vertigo, so only the little-known Plains Cuckoo (Spanish variety) is able to migrate to Switzerland. Sadly, because Switzerland is famous for its mountains, the Swiss have secretly folded up most of their Plains to make them, hence significantly reducing the habitat available to said cuckoo.
The above is exacerbated by the need for the Swiss to capture cuckoos in order to achieve their characteristic yodelling speech as the cuckoo, stuffed down their Swiss Army pants (regulation issue wear for every citizen in that highly-ordered & compliant society) pecks rhythmically at the gentleman's love sausage (thereby giving rise to the term pecker, incidentally) in order to achieve peak yodel.
Caught between these two rather remarkable instances, it's little wonder that the last Swiss cuckoo died in the late C19th. The Swiss nation was so overcome with grief that they created an industry out of horological cuckoo tributes to their part in their extinction (hence their correct name - cuckoo crock)
I guess it's obvious now I've explained it to you, but I'm rather surprised someone hasn't mention this already.
Here's your Swiss undies, should you come across a cuckoo looking as if it's at (or hankering to be at) a loose end:
https://www.ebay.co.uk/itm/2-x-Swis...arm-Underwear-Original-Military-/162957546591