Pigeon

Hi to days ago I freed a pigeon that was stuck in the summer house in garden.  it sat on lawn all afternoon and then went.  It keeps comming back and sitting in bushes (scarey as we have a cat) but it is all "puffed up" a friend has said this means it is ill? As I know nothing about pigeons can anyone give advice? should I rescue it and leave it overnight in catbox in summer house with food and water to re-coop? I am worried incase it has bashed its head and is disorientated.

what do you think? Today it was sat under a bush in pouring rain and wind all "puffed up"