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

Phalanx 3 digiti 3 posterior For the phalanx 3 dig. 3 post. (Plate XXXI, Figure 1; Plate XLV, Figures 19-22) the same is relevant as for the phalanx 2 dig. 2 post., but in this case the ratio constituted from the width of bone ends (PW/DW) is a good key too. This value is the higher in the Hobby, while the lowest in the Lesser Kestrel and the Kestrel. Phalanx 4 digiti 3 posterior The length of phalanx 4 dig. 3 of Hobby, Merlin and Kestrel is more or less equal, and considerably shorter in the Red-footed Falcon and Lesser Kestrel. In the Hobby and Merlin compared to the its height the proximal end of the bone is narrower (the PH/PW value is higher) than in the Kestrels. The end of the bone is widest in the Lesser Kestrel and Kestrel. In the case of this phalanx on the medial side of the corpus phalangis there is a longitudinal crest (referred to as crista medialis). The crista medialis is considerably higher in the Kestrels than in the true Falcons. In the Hobby and Merlin in lateral view the tuberculum extensorium is thicker, and its end is more club shaped than in the Kestrels. In the Red-footed Falcon this tuberculum is not only thinner but also shorter. On the plantaro-lateral side of the proximal end of the bone the back-bending bone-rim on the section between the cotyla articularis and tuberculum flexorium major is the widest and thickest in the Kestrel, and still quite big in the Hobby and Merlin. But in the Red-footed Falcon the back-bending is either very slight or completely missing. The back-bending bone-rim on the plantaro-medial side is always considerably smaller and thinner than on the lateral side in all the species, in the Red-footed Falcon this is also completely missing. Summary Falco subbuteo: - the proximal end of the bone is high and thin, - the tuberculum extensorium in lateral view is thick and its end is knobby, - the crista medialis is small. Falco columbarius: - the proximal end of the bone is thin, - the tuberculum extensorium in lateral view is thicker and its end is knobby, - the crista medialis is small. Falco tinnunculus: - the talon is big, the proximal end of the bone is wide, - the tuberculum extensorium in lateral view is thin, - the plantaro-lateral bone-rim is thick, - the crista medialis is big, and strongly elevated. Falco vespertinus: - the talon is small, the proximal end of the bone is wide, - the tuberculum extensorium is short, in lateral view it is thin, - the plantaro-lateral bone-rim is very thin or missing, - the crista medialis is big, and strongly elevated. 60