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

values of the proximal end of the bone (PW, PH) are large (GL/PW value is low), and the height of the distal end of the bone (DH) is relatively small. Hence the PH/DH ratio is higher in the Merlin than in the rest of the species. This value is the lowest in the Kestrels. Furthermore in the Merlin the PH-DH value is also high, e.g. the pila cranialis narrows more in distal direction than in the other species (cranial view). If we calculate the ratio of this value and the total length of the phalanx (which is low anyway in the Merlin), we get a valuable ratio (GL/PH-DH). As a consequence of the small proximal end of the bone in the Lesser Kestrel the GL/PW value is high. The phalanx of the Kestrel and Red-footed Falcon can not be safely separated by the size measurements, only the small and large individuals can be identified. In the Kestrel the faciès articularis metacarpalis curves less than in the other species, where the faciès bends in right angle on the dorsal part (proximal view) (Plate XXXVIII, Figures 3-4). In the Kestrel the caudal edge of the phalanx is usually more arched, and its plate widens slightly in distal direction, while in the rest of the species the middle section of the caudal edge is straighter, and approximately parallel with the cranial edge (Plate XXXVII, Figures 14-15). In the Red-footed Falcon in cranial view the pila cranialis stronger narrows distally from the proximal end of the bone than in the Kestrel. This is partly due to the fact that in the Red-footed Falcon the tuberculum in the middle of the ventral edge of the proximal end of the bone is larger than in the Kestrel. Summary Falco subbuteo. - the absolute measurements of the phalanx are very large, - the proximal end of the bone is wide (PW/PH value is high). Falco columbarius: - the phalanx is short, - the proximal end of the bone is relatively large (GL/PW value is low), - the GL/PH-DH value is very low. Falco tinnunculus: - the faciès articularis metacarpalis curves less than in the other species (proximal view), - the caudal edge of the phalanx is more rounded than in the other species, and widens slightly in distal direction (dorsal view). Falco vespertinus: - the proximal end of the bone is relatively small, - the GL/PH-DH value is high, - the tuberculum in the middle of the ventral edge of the proximal end of the bone is large. Falco naumanni. - this phalanx is the smallest in this species, - the proximal end of the bone is relatively small (GL/PW value is high). Phalanx dis ta I is digiti majoris (phalanx 2 digiti 2 anterior) This phalanx is the largest in the Hobby, and the smallest in the Merlin. There is a considerable difference between these species. They can be distinguished both by the length of the phalanx and the size of the articular part, and even the sexes can be distinguished. 34