In my previous blog post, I noted that Ridgway’s hawk (Buteo ridgwayi) has been lumbered with a misleading common moniker, taxonomically speaking. As a member of the genus Buteo, it is in fact a buzzard and not a true hawk, all of which are species of the genus Accipiter. Both genus are indeed members of the same family, Accipitridae. Commenting on the aforementioned post, Snailquake queried the difference.
It is true that there are a great many similarities between hawks and buzzards and that the common names associated with each group often differ between countries. For example, vultures (most commonly Turkey Vultures, Cathartes aura) in the US are commonly saddled with the name ‘buzzard’ while true buzzards are often referred to as hawks. In this context, buzzard is a word which carries negative connotations, as exemplified by the use of the word ‘buzzard’ to define one who scrounges (scavenges). Despite a lack of consistency in terminology, there are some features which may be used to distinguish between Buteo and Accipiter*:
- Buzzards generally have longer wings which exhibit long, splayed primary feathers, in contrast to the short, rounded wings of hawks.
- Hawks exhibit a longer, narrower, more manoeuvrable tail, giving then greater aerial agility. Buzzard tails are generally broad and rounded.
- Buzzards are generally slower fliers, poorly adapted to pursuing swift prey. This contrasts with hawks who rely on great bursts of speed to ambush prey items.
- Hawks often inhabit and hunt in more densely wooded areas whereas buzzards often require more open habitat.
- Hawks tend to have longer legs.
- Hawks exhibit a procoracoid foramen; an opening in front of the coracoid bones which is reduced or absent in other species (Olson, 2006).
Ridgway’s Hawk is, of course, not the only species to be saddled with a taxonomically incorrect common name. There are many examples of harriers and buzzards being labelled hawks, including Red-tailed Hawks (Buteo jamaicensis) and Marsh Hawks (Hen Harriers, Circus cyaneus). Even the Peregrine Falcon (Falco peregrinus; belonging to the family Falconidae) has been called the ‘Duck Hawk’. Thus it is evident that there is great variation in common accipitrid nomenclature which is largely dependant on location. Here in the U.K. we have only two true hawk species – the Sparrowhawk (Accipiter nisus) and the Goshawk (Accipiter gentilis) – amongst our birds of prey which also include the Common Buzzard (Buteo buteo). It is likely that the British once called all raptors ‘hawks’ (the American propensity for such may be a cultural carry-over) but that has since been superceded by recognition of the true phylogeny.
*Note that these are not hard-and-fast rules.
Olson, S.L. (2006): Reflections on the systematics of Accipiter and the genus for Falco superciliosus Linnaeus. Bull. B.O.C. 126: 69-70. [PDF link]