I've been watching a pair of starlings carefully pulling individual leaves off my newly planted catmint plant then gathering them up and flying off. No idea why they would do this so googled and it seems to be something that starlings and blue tits have been seen to do with mint leaves, possibly for the antibacterial benefits, they line the nest with them.
No specific mention of catmint though but perhaps my Walkers Low smells minty enough for the starlings.
https://nestwatch.org/connect/blog/avian-apothecaries/