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

Although the Kestrels are different regarding their size, the phalanges are approximately equal, and are in intermedier position between the former species (Plate XVIII, Figure 1). In the Kestrel the proximal end of the bone is relatively wider (PW) than in the Red-footed Falcon and Lesser Kestrel, and hence the GL/PW ratios are lower, the PW/PH ratios are higher than in the latter two species. In the Hobby these ratios are similar to the ones found in the Red-footed Falcon (also the PW/PH value in the Merlin), but it is caused instead of low PW values by the high GL and PH values. In the Merlin due to the short phalanx all the ratios calculated with GL are very low. In the Hobby the corpus phalangis in caudal view is narrow, its edges are more or less parallel, its apex is truncated and tilted. In the Merlin the corpus is wider, its edges are converging slightly towards the apex, and the apex is more blunt, or truncated in right angle. The phalanx of the Red-footed Falcon is similar to that of the Hobby, the corpus is long and thin in caudal view, its edges are parallel. In the Kestrel the phalanx is relatively shorter, the corpus is slightly wider, and its edges are slightly converging toward the apex. The apex is sloping, truncated and pointed in both species. In the Lesser Kestrel the corpus phalangis is narrow, at the collum (it is located next to the proximal end of the bone) widens strongly toward the proximal end (Plate XXXVIII, Figures 17-21). Summary Falco subbuteo. - the phalanx is large and long, - the proximal end of the bone is high (PH), - the corpus phalangis is narrow, its edges are more or less parallel (caudal view), - the apex is pointed, truncated and tilted. Falco columbarius: - the phalanx is extremely short, - the proximal end of the bone is high (PH), - the collum part and the corpus are wide, its edges are converging toward the apex (caudal view), - the apex is blunt or truncated in right angle. Falco tinnunculus: - the phalanx is relatively short, - the proximal end of the bone is wide (PW), - the corpus is wider, its edges are slightly converging toward the apex (caudal view). Falco vespertinus: - the phalanx is relatively long, - the proximal end of the bone is narrow (PW), - the corpus is narrow, its edges are parallel (caudal view). Falco naumanni: - the phalanx is relatively long, - the proximal end of the bone is narrow (PW), - the collum part is wide. Phalanx digiti minoris (phalanx 1 digiti 3 anterior) The single phalanx of the third digit shows similarities to the formerly described phalanges. The Hobby has got the longest phalanx, but can only be separated from the Merlin if we distinguish the sexes. The phalanx of the Kestrel regarding its size is in between the former 35