To say one is feeling a “box of birds” to mean feeling good or “crook” to mean feeling bad

Context: The informant is half-Indian and half-New Zealander, with her dad being an immigrant from New Zealand. At one point, the informant’s paternal great grandmother was over for Christmas and she had caught a cold, so her family took her to the doctor, and according to the informant when the doctor asked her how she was doing she said “Well yesterday I was a box of birds and now I’m feeling a bit crook”.

Analysis: According to the informant, “box of birds” is used to describe someone who’s doing or feeling well, while “crook” is used to describe someone who is doing poorly. The informant’s family is from New Zealand, and the informant only remembers her great-grandmother being the one to use it. In doing some research, I found that “box of birds” is a common idiom in both New Zealand and Australia used to describe feeling good/doing well, due to one “feeling chirpy”, which the informant agreed was accurate to her family’s definition and context of use. “Feeling chirpy” is a similar nature-based idiom, referring to someone who is cheerful and in good spirits, similar to birds chirping excitedly. Having that much energy would logically require one to be in good health. It is unknown if both expressions were derived independently, but if so, that would indicate an instance of polygenesis, with at least two independently derived expressions relating health/energy with birdsong. It stands to reason that birdsong, like other behaviors that are consistently observed by a large amount of people would make their way into the vocabulary. Using them as comparisons would evoke a shared experience and facilitate understanding.

In the same regions, the slang “crook” refers to feeling bad or in bad health but seems as if it has less clear origins; crook comes from crooked, which can mean incorrectly or wrongly shaped, which might be where the slang comes from. Both seem to be instances of folk speech, either evolving from common