Folia Historico-Naturalia Musei Matraensis - A Mátra Múzeum Természetrajzi Közleményei 21. (1996)

Falco vespertinus: - the phalanx is short, the corpus phalangis is comparatively wide, - the tuberculum collatérale laterale and the tuberculum extensorium are small, - the plantar side of the corpus is wide, and flat, - the distal part of the corpus in lateral view is strongly bending, - the capitulum phalangis in lateral view is arch shaped, - the depressio epicondylaris medialis and lateralis are relatively deep, - the sulcus intercondylaris is very shallow. Falco naumanni: - the phalanx is short, the corpus phalangis is wide, - the tuberculum collatérale laterale and tuberculum extensorium are small, - the plantar side of the corpus is wide and flat, - the distal part of the corpus in lateral view is strongly bending, - the capitulum phalangis in lateral view is arch shaped. Phalanx 2 digiti 1 posterior The talon of the first phalanx is the longest in the Kestrel, but that of the Merlin is also longer than that of the Hobby. And consequently in the Kestrel and Merlin the height of the proximal end of the bone relative to the length of the talon is smaller (GL/PH value is higher) than in the Hobby, Red-footed Falcon and Lesser Kestrel. The ratio of the height and width of the proximal end of the bone (PH/PW) is the highest in the Merlin and Hobby, while in the Red-footed Falcon and Lesser Kestrel is lower. The PH/PW ratio is lowest in the Kestrel. The reason of this phenomenon is partly the fact that in the Kestrel on the two sides of the proximal end of the bone on the section between the cotyla articularis and tuberculum flexorium major (from the foramina vascularia laterally and medially) the bone rim bending over the horn cover of the talon is wider and thicker than in the other species, and hence increases the with of the proximal end of the bone (PW). This bone rim is the narrowest (proximo-distal direction) and the bones at the two sides are the most narrowly arched (proximal view) in the Red-footed Falcon and Lesser Kestrel, and hence the end of the bone is narrower in these species (PH/PW values are comparatively high). In the Kestrel and Red-footed Falcon the corpus phalangis is higher and wider (the talon is thicker), than in the Hobby, Merlin and Lesser Kestrel (Plate XXVIII, Figure 2). In the Hobby and Merlin in lateral view the end of tuberculum extensorium is wider and more knobby than in the Kestrels. In the Red-footed Falcon and Lesser Kestrel this part is even shorter than in the other species (Plate XLIV, Figures 11-15). The talon of the first (and 2nd) toe of the Red-footed Falcon and Lesser Kestrel can not be mixed with that of the other species as a consequence of their size, but can be misidentified as the talon of the fourth toe of those species. But from the Kestrel they can be separated on the basis of the ratio of the height and width of the proximal end of the bone, and furthermore by the size of the rims of the bone. The talon of the fourth toe of Hobby and Merlin differs from the talons of the first and second toes of Red-footed Falcon and Lesser Kestrel in the length of the tuberculum extensorium. Summary Falco subbuteo: - the proximal end of the bone is high, narrow, - the tuberculum extensorium is long, and its end in lateral view is knobby. 52