Eurasian Sparrowhawk

The Eurasian Sparrowhawk is a small Accipiter, roughly the size of a pigeon. It has a larger, stronger cousin, the Eurasian Hobby, with whom identification can be confused unless one notices the size difference. They both share the accipiter silhouette, characterized by wide, short, round-tipped wings and a long tail, yellow eyes, and finely barred underparts in adults. Appreciating size is therefore fundamental. The Sparrowhawk has a long, thin tail, cut square-end (shorter, wider and round-tip for the Hobby). If one assigns a value of 1 to the width of its wing, the length of its tail will be around 1.3 (1.08 to 1.1 for the Hobby).
There is sexual dimorphism in the Sparrowhawk. Adult male is typical with its slate-gray upperparts and red patches on the cheeks, flanks and barring of the underparts. Iris is orange. Adult female, noticeably larger, is brownish-gray to gray-brown above, and barred brown below. Iris is yellow and she usually has a pale eyebrow. She can be confused with the Hobby. The juvenile resembles female but its upperwing coverts are edged red and its underparts more coarsely barred.
At rest, the long, slender tarsi of the Sparrowhawk are diagnostic. In flight, its rapid, clipped and jerky wing beats are distinctive. The adult Hobby has no red, a distinct pale eyebrow, more finely barred gray-brown underparts, broad chest, strong tarsi, broader at base and with round-end tail. Its wing beats are slower.
Finally, a trick! When seen from underneath, an adult in flight has to be watched for their secondaries.These are clearly barred with brown on the Eurasian Sparrowhawk while the bars are more faded and less visible on the Common Buzzard. Helpful on photos.