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

Falco naumannï. - the whole lamina pygostyli is high only at the basis, sometimes strongly narrower at the middle (lateral view), - the basis pygostyli is narrow (GW value). Femur The ratios of femur lengths between the studied species is different from the formerly described bones. The femur of the Eleonora's Falcon is comparatively short, while the femur of the Merlin is quite long, and hence the femur lengths of the two species considerably overlap. It is just the opposite of the formerly described wing measurements. The Hobby, Merlin and Kestrel is more or less equal in this feature, but on average the Merlin has the longest femur and the femur of the Kestrel is usually longer than that of the Hobby. The femur of the Red-footed Falcon and Lesser Kestrel is very short, and hence can be separated from the other species on the basis of the length very easily (Plate XXIII, Figure 1 ). The transverse measurements are sometimes overlapping, especially so in the case of the height values of the end of the bones (PH, DH). In the Merlin compared to the length the width measurements are lower than in the Hobby, Eleonora's Falcon and Kestrel. And hence the GL/PW, the GL/PH and GL/CW (etc.) values are high. The femur of the Hobby can be separated from that of the Kestrel's by the GL/CW ratio quite well, as the femur of the Hobby is wider. The two species is also separated by the PW/PH ratio, as the trochanter femoris is larger, the crista trochanteris is higher and more prominent in the Kestrel than in the Hobby. The relation of these two values is shown in Plate XXIII, Figure 2. In the Eleonora's Falcon the end of the bone are wide (PW, DW), so by these values both in absolute terms but also as compared to the length (GL/PW) this species is easily separated from the rest (Plate XXIV, Figure 1). The femur of the Lesser Kestrel is very hard to tell apart from the femur of the Red-footed Falcon, but the transverse measurements of the Lesser Kestrel are a bit larger. The corpus femoris is relatively wider, the diameter of the caput femoris is larger, the distal end of the bone is wider and the trochanter femoris is a bit larger of the Lesser Kestrel than in the Red-footed Falcon. Consequently the femurs of the two species can be separated by the GL/CW, GL/CD, GL/DW and GL/PH ratios (Plate XXIV, Figure 2). The situation is further complicated by the fact that the sexes of the same species sometimes exhibit larger differences than two different species (for example GL/CW value), namely in the females the transverse measurements are larger and the bones are wider than in the males. Morphologically the femur has very good identification features. Its longitudinal axis in lateral view is more curved in the Merlin and Kestrel than in the Hobby and Red-footed Falcon. The corpus femoris is the most curved in the case of Merlin, and less curved in the Red-footed Falcon. In the Kestrel the curve of the corpus is not even, at the distal end there is a stronger breaking point (Plate XLI, Figures 9-12). In the Merlin the width of corpus femoris is more even, toward the ends of the bone less widening than in the other species. This feature is especially prominent at the medial side of the proximal end of the bone (cranial view), as in the case of the Merlin the contour line is straight till the collum femoris, while in the Hobby it is weakly in the Kestrel strongly curved into medial direction. The Red-footed Falcon is in intermediate position between the Hobby and Kestrel regarding this feature. The corpus femoris most narrow at the middle in the Kestrel (Plate XLI, Figures 13-16). The shape of trochanter femoris is also different in the studied species. In lateral view the 42