ID tips & tricks
VARIATION AND DIMORPHISM
One of the confusing aspects of identification of birds of prey is variation, particularly in plumage in the population (intraspecific variation). This is particularly prevalent in Buzzard and the rare Honey Buzzard, where birds can vary from almost white to dark brown with everything in between. Many birds of prey are sexually dimorphic, meaning that males and females look different. In general (though not always) female raptors are bigger than males. The harriers and the Kestrel also have distinct adult male and female plumages. Male Kestrels, for instance, have grey heads and largely grey tails, whereas females are barred and streaked brown. Harriers are also greyer in the smaller males, browner in the females. Tail feathers from a Kestrel (left: male right: female)
FALCON OR ‘HAWK’
Diurnal raptors come in two main broad groups, namely the falcons and the rest (very loosely, the hawks). Falcons are in a different family and some taxonomists think they are only very distantly related to the remainder. Falcons are generally smaller, slimmer, dark-eyed, neater, pointed winged speed merchants, and also include the habitually hovering Kestrel. The hawks, kites, harriers and eagles are broader winged, often with distinctly fingered primary feathers. They vary from small (like the Sparrowhawk) to very large (eagles), often have pale eyes and are generally slower flying.
A White-tailed Eagle can be up to five times larger than a Sparrowhawk (which is about 29cm long and a wingspan of 58cm). The largest recorded is 92cm long, with a wingspan of 240cm.
Dark-morph Buzzard and pale-morph Buzzard (inset)