Kestrel

Although birds of prey are frequently seen flying over the Science Site (red kites have been seen overhead during the last couple of years) the raptor that you are most likely to encounter there is the kestrel. You'll often see one hovering over the grassland just north of Hollingside Wood, behind the Mountjoy Buildings, hunting mice and voles. From time to time they also breed in Hollingside Wood.... which is good news, since kestrels have been declining in some parts of Britain.

The little feather that you can see sticking out of the leading edge of each wing, about half way along, is the alula, which allows the bird to hang in the wind motionless, while it scans the ground below for prey. Anatomically, the alula is the bird's thumb and the feather controls airflow across the leading edge of the wing when it's held at a high angle attack, generating maximum lift without stalling. Leading edge slats on short take-off and landing aircraft serve the same purpose.