This morning a lively chorus of Blue Tits and Chaffinches alerted me to a hunting Sparrowhawk in the park. It flew over and landed on a branch of a Horse Chestnut nearby. Luckily, there was a clear line of sight between the still leafless branches from where I was standing. Its russet underside and small size revealed it was a male. It only sat there for a couple of minutes, scratched its chin, and flew across the road to a willow where I've seen Sparrowhawks sitting before. As it flew, the small birds started calling nervously again. I approached, and managed to find an angle where I could get a clear view. He didn't notice me, instead, he was interested in the birds mobbing him from a safe distance over him, and looked intently.
In the willow, under the cover of its curtain of branches the hawk appeared relaxed. It turned to the sun, raised its feathers and shook them leaving them fluffed out, an action called 'to rouse' amongst falconers (photo below). I was impressed by his long chest and flank heathers, thinly lined with white. Sparrowhawks also have long white undertail coverts, which they fluff out when they display over their territory.
The male turned its back to me again. Every time it changed position, the birds called echoing his movements.
This was the last photo I took from the five minute encounter. Followed by the alarm calls of the small birds, the Sparrowhawk flew away, probably trying to surprise some prey still not alerted to its presence.