Many, many years ago a niece sent me a little stuffed toy of a duckling, who was promptly named Jemima, (Mima for short) and adopted as one of the family, and whenever we go on holiday, she comes, too and has her photo taken at venues to prove it. My mother knitted little hats, scarves and waistcoats so she -- Mima, not Mum -- wouldn't get cold, and at my brother's wedding Mima attended in finery while my sister's toy polar bear had a top hat and bow tie. (And people wonder where I get my nonsense from....)
Anyhow, since then the Judicial Helpmeet and I have never referred to people we like as Spring Chickens, they're Spring Ducklings, as ageless as Mima.