Occasionally his concentration lapsed and he spent time stretching and preening.
Here he is also showing off his tail feathers.
Eventually a blue tit turned up despite the constant alarm calls from nearby bushes. The sparrowhawk attacked but the blue tit dived into the safety of a thorny gooseberry bush right in front of me. It was only 50cm above the sparrowhawk, which was now on the ground, and was very agitated but too scared to fly away. At one point there were three blue tits in the bush all jumping about and calling alarms but eventually they all made a dash to the safety of a holly bush.
Then a great tit arrived and wasn't so lucky. The sparrowhawk briefly took it back to the post but found there wasn't room enough so flew a short distance away to pluck and eat its prey.
This bird is an adult male, with beautiful RAF blue feathers on his head and back and a rufous tinge to the chest feathers which is less marked than in some other birds. His eyes are yellow-orange (and will become darker with age). He can turn his head nearly all the way round, like an owl, and has white marks on the back of his head.
The male sparrowhawk is much smaller than his mate, a feature called reversed sexual size dimorphism. It's a very efficient arrangement as the two birds hunt different prey, the male catching tits, finches, etc while the female goes after blackbirds and pigeons. They only need small birds when the chicks are being brooded by the female but larger food items once she can leave them in the nest to hunt.
The Eurasian sparrowhawk is Accipiter nisus. Accipiter is Latin for hawk. Nisus was the King of Megara and was killed by his daughter Scylla after she cut off a lock of purple hair which kept him from harm. Nisus was transformed into a sparrowhawk (or an osprey or a sea eagle, depending on which story you read).
Thomas Bewick engraved a sparrowhawk for his A History of British Birds (1797).
Sparrowhawks are now fairly common birds but were severely affected by DDT, aldrin and other pesticides used in agriculture after the Second World War and the population crashed. It recovered slowly after the chemicals were banned and is now stable.
Sparrowhawks are birds of woodland and gardens are are more common in eastern parts of the country. They have made a good recovery in East Anglia where they were almost extinct.
Sparrowhawks are fairly common visitors to gardens, hunting small birds attracted to feeders. These BTO Garden BirdWatch data show that fewer visit in late spring when the woods and hedgerows are full of fledgelings.
Read more about sparrowhawks here. You can watch a wonderful short video from the BBC Natural History Unit about a hunting sparrowhawk here. Watch a BTO video on identification of sparrowhawk and goshawk here. And listen to the BBC Radio 4 Tweet of the Day on sparrowhawk here.