I'm an owl in lark's clothing, or, at the moment, a lark in owl's clothing.
When I am at my best, fittest, happiest, most active and most productive, I am in bed by 10pm at the latest, and up not long after 5am. Particularly wonderful in the summer, when one has the dawn world all to oneself and all the non-human creatures

However I can also operate, and have spent most of my life operating, at the other extreme - finding it hard to get to bed before 2am and then difficult to get up and going early enough for the demands of my life, be it office or farm.
Mum is a night owl, for sure, so it's her fault I have a tendency in that direction. I'm currently trying to kick myself back into the lark pattern - but this usually hits a problem when we have calvers and I get up and check them in the night, then it starts to feel easier just to stay up until I do the late-night check... and pretty soon I'm back to being an owl again.
