Whilst taking down our old nestbox from last year, I noticed a very large, (well, large for a chrysalis anyway, at around 3cm long), chrysalis hidden in my old Scotland fleece which acted as wadding around the old (and new, now) birdbox.
This wonderfully-coloured chrysalis (quite a spectacular example in fairness) belongs to the Large (Cabbage) White Butterfly - the scourge of all gardeners' nasturtiums everywhere!
This butterfly has the rather unusual habit (among butterflies) of attaching its chrysalis to a window sill (or fleece?!) in an upright manner, ie head up, rather than hanging with the head down, as most pupae are formed.
If you look closely at my photographs, you may be able to make out the silken thread, about two thirds along the chrysalis (from tail to head) which enables this unusual behaviour to occur.
Luckily we have no nasturtiums, or cabbages for that matter, nor do we intend to plant any in the future - just potatoes for us this year I think, and maybe one or two courgette plants.
I didn't see many of the adult White Butterflies this summer, in the garden, so I feel quite lucky that we've got a little chrysalis overwintering with us...
In the meantime, its gone back into the fleece, which is now wadding for the new box (see above post).