Some Thoughts on Kleinschmidt's Peregrine Falcon, Falco kreyenborgi

Abstract

This paper discusses the current state of knowledge regarding Falco kreyenborgi Kleinschmidt and, in summary, arrives at the following conclusions: 1) For individuals identified as adult F. kreyenborgi, it could be a clear phase or mutation of Falco peregrinus cassini. However, while this possibility is not excluded, it is unlikely, given the convincing conclusions of Stresemann & Amadon (1963). It could then be a separate species or a subspecies of Falco pelegrinoides. In the latter case, it would demonstrate, contrary to the findings of Dementiev & Ilytschev (1961), that F. peregrinus and F. pelegrinoides are conspecific. Finally, if it were a subspecies of F. pelegrinoides, what zoogeographical interpretation would be most appropriate? The case is somewhat complicated, but it has certain analogies, such as the current distribution of falcons belonging to the group gyrfalco (rusticolus auct.) – cherrug – jugger – mexicanus – subniger. It could be a polytopia or a paramorphogenesis. 2) For individuals identified as juvenile F. kreyenborgi. To ensure the identification of this material, it is necessary to study the molt stage of the plumage, but no specimens have been available for this purpose. Furthermore, one might ask: are these young individuals truly conspecific with adult kreyenborgi? Regarding coloration, they appear to be more similar to adult Asian saker falcons. Their legs are bright yellow, unlike those of F. peregrinus sensu prima libreta annuta, but, on the other hand, the legs of juvenile F. pelegrinoides are also orange-yellow. The wing formula of these specimens, according to the photographs studied and also in accordance with Stresemann & Amadon, is 2.1.3, that is, like that of peregrine falcons, not like that of saker falcons. The relative length of the toes, according to Stresemann & Amadon, is also the same as that of peregrine falcons. According to these authors, the wing length is 299 mm for the Kovacs specimen and 305 mm for the Olrog specimen; both individuals are males. These measurements are considerable for the F. peregrinus group, but small for the sacr group. The tail of the Olrog-Kovacs specimens is relatively long, unlike what occurs in the F. peregrinus–F. pelegrinoides peregrines.