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

Phalanx 3 digiti 4 posterior Among the phalanges of the 4th toe the third one shows the greatest length differences between the species. The Hobby, Merlin and Kestrel do not overlap in this measure. The phalanx of the Kestrel is very short and hence considerably overlaps with that of the Red-footed Falcon (Plate XXXIII, Figure 1). The ratio of the length of the phalanx and the width of corpus phalangis (GL/CW) well separates the species. This value is highest in the Hobby and lowest in the Kestrel. The Lesser Kestrel is placed between the Red-footed Falcon and Kestrel by this ratio (Plate XXXIII, Figure 2). In the Merlin the ends of the bones (especially the capitulum phalangis) are relatively wider than in the Hobby. The GL/DW and GL/PW ratios separates very well these species. In the Hobby the section of the plantar side between the ends of the bones is straight, in the Merlin this section is concave (lateral view). In the Red-footed Falcon the plantar side from the proximal end of the bone to the capitulum phalangis is straight (but not parallel with the dorsal edge of the corpus) in the Kestrel and Lesser Kestrel this part is arched (Plate XLV, Figures 26-28). In the Hobby the tuberculum intercondylare dorsale is big. In the Merlin this part is smaller, in the Red-footed Falcon hardly visible and in the Kestrel missing (Plate XLV, Figures 26-28). In the Hobby and Merlin - as opposed to the Kestrels- the capitulum phalangis is small, and in lateral view its dorsal edge is either only slightly or not extends above the dorsal line of the corpus. In the Kestrels proximally from the capitulum phalangis on the dorsal side there is a strong incurvation that is strongest in the Red-footed Falcon. In the Hobby and Merlin this incurvation is negligible (Plate XLV, Figures 26-28). In the Kestrel and Lesser Kestrel the distal edge of the condylus medialis extends only slightly further in distal direction than that of the condylus lateralis. In the other species this difference is greater, especially in the Red-footed Falcon and the Hobby (Plate XLV, Figures 39-43). In the Red-footed Falcon the sulcus intercondylaris is deeper than in the Kestrel and Lesser Kestrel (Plate XLV, Figures 41-43). In the Red-footed Falcon the medial and lateral sides of capitulum phalangis diverge stronger in the plantar direction (distal view) than in the rest of the species. The sides of the distal end of the bone are nearest to the parallel in the Kestrel. Summary Falco subbuteo: - the phalanx is long, and relatively thin, - the section of the plantar side between the ends of the bone is straight (lateral view), - the tuberculum intercondylare dorsale is big, - the dorsal edge of the capitulum phalangis either not or only slightly extends over the dorsal line of the corpus (lateral view), - on the dorsal side, proximally from the capitulum phalangis there is almost no incurvation (lateral view). Falco columbarius: - the phalanx is long, and the ends of the bones are relatively wide, - the section of the plantar side between the ends of the bone is arched (lateral view), - the dorsal edge of the capitulum phalangis either not or only slightly extends over the dorsal line of the corpus (lateral view), 64