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

Tibiotarsus As regards to the longitudinal measurements of the tibiotarsus the parameters of Merlin, Hobby and Kestrel are largely overlapping. But if we examine the average values the Kestrel has the longest tibiotarsus among these species. The tibiotarsus of the Merlin is a bit shorter than that of the Hobby's (just opposite the case of the femur), its minimum value in the Merlin is very close to the maximum value of the Red-footed Falcon. In the case of the Hobby and Merlin the difference between the length of the tibiotarsus of the sexes is much larger than in any other bone. The tibiotarsus of the Eleonora's Falcon is relatively short, the only measured specimen's length was equal to the maximum value of the Kestrel's. The tibiotarsus of the Red-footed Falcon and Lesser Kestrel is short, but the Lesser Kestrel's tibiotarsus is only slightly shorter than the Red-footed Falcon's (Plate XXV, Figure 1). The transverse measurements in the two size groups (Merlin, Hobby and Kestrel in the one group, Red-footed Falcon and Lesser Kestrel in the other) are considerably overlapping, and hence only the ratios are adequate for telling apart the species. In general terms it is characteristic that the absolute transverse measurements of the Hobby are greater than that of the Merlin's. This relation is also true between the Kestrel and Hobby, except the height measurements the distal end of the bone (DH), which is greater in the Kestrel. The latter species can be separated from the Hobby and the Merlin if we take into account the ratios calculated with the help of longitudinal and transverse values. As a consequence of the great height values of the distal end of the bone the PT/DH and DW/DH ratios are also adequate for the identification of the species. In the Merlin as a consequence of the greater length of the tibiotarsus the GL/CW and GL/CT ratios are considerably high. The GL/CT ratio is also high in the Kestrel, but as the corpus is wide a bit in this species the CW/CT ratio is the highest in this case. The corpus width related to the length is shown in the Plate XXV, Figure 2. In the Red-footed Falcon the transverse measure of the proximal end (PT) is greater, but the sizes of the corpus and the distal end of the bone are smaller than in the Lesser Kestrel. The two species is quite well separated according to the GL/PT and PT/DH ratios. In the Merlin the corpus tibiotarsi in distal direction from the connection point of the fibula is wider than in the other species. This caused by the more prominent edge as a continuing of the fibula, and hence the corpus is wider. A further characteristic is that consequently the connection of the fibula and the corpus tibiotarsi is smoother and lacks the breaking as compared to the other species. In the Merlin and Hobby compared to the Kestrel and Lesser Kestrel the crista patellaris is less prominent in the proximal direction. But the crista interna (BALLMANN, 1969), in the two first species is higher in proximal direction, and strongly curved. And hence the height difference between the crista interna and crista patellaris is greater in the Merlin and Hobby than in the Kestrel and Lesser Kestrel (Plate XLII, Figures 13-17). In the Red-footed Falcon the crista patellaris has got a depression near the proximal end of the crista cnemialis cranialis (proximal from the sulcus intercristalis), and hence the crista patellaris is waving. In the other species this depression is missing (Plate XLII, Figure 16). In the Hobby and Merlin the area interarticularis and the faciès articularis lateralis (they form a unit) proximally is more protruding than in the Kestrels. And hence the difference measured between the greatest length (GL), which includes the crista interna and the length of the tibiotarsus measured in the longitudinal axis is smaller than in the Kestrel and Lesser Kestrel, where the crista interna proximally higher and the area interarticularis is lower. In the Red-footed Falcon the area interarticularis and the faciès articularis lateralis is more protruding, and hence this species is intermediate regarding this marker. 45