Moroccan reed warbler? (1 Viewer)

"At Larrache, Morocco, besides the spring- and autumn-migrant Reed Warblers A scirpaceus from the western half of Europe, birds also occur that breed there, and probably do not migrate away. Local researchers already knew that Moroccan sedentary birds differ from European migrants in their short wings, and that adults perform a rapid complete moult in late summer. During a study aimed at the occurrence of Aquatic Warblers A paludicola at Larrache in the second half of September 2009, a number of Moroccan reed warblers were caught, from which it appeared that these birds also differ in size and colour from migrant Reed Warblers. This was the reason to start further research, the preliminary results of which are presented in this article. Besides collecting feathers for future isotope and DNA testing, various measurements were taken and the wing formula was assessed for a total of 91-94 specimens (while documentation with photographs and videos took place). The nine measurements [taken] were the lengths of the wing, longest primary (p3), tail, bill to feathering, bill to skull, head including bill, tarsus and hind claw, and the width of the bill at the level of nostril. From statistical analyses of these biometric data, it appears that Moroccan reed warblers are smaller than European migrants also caught there, without overlap, in all measurements including wing length. Also for the wing formula, nine variables were recorded, among which the distance between the longest (p3) and other primaries (p2-7), the distance from the outermost primary (p1) to the primary coverts, the length of the emargination on p3 and the length of the notch on p2. The statistical analyses here result in the conclusion that Moroccan reed warblers have a rounder wing tip with primary tips closer to one another, and a longer emargination on a shorter p3 than in European migrants. During the ringing other differences also surfaced. So, many of the caught Moroccan reed warblers appeared to carry an unusually high number of parasites. Also the moult strategy differed, as in early September up to five primaries, five secondaries, and all the tail feathers were replaced simultaneously. European birds usually replace at most the middle tail feathers before they reach their tropical winter range. Additionally Moroccan birds differed from European migrants in darker bare parts, with dark gray legs and contrasting yellow soles (recalling African Reed Warbler A baeticatus from Burundi and Senegal), and darker orbital ring and lower bill. The fresh plumage differed in the pale brown color that extended further below, sometimes not only on throat and flanks but on the entire underparts, and also on the head including the eyebrow. In 2010, further research will follow to assess the distribution, breeding biology, and vocalisations, and also more birds will be caught to be measured. Additionally, data are being collected about the western subspecies of African Reed Warbler A b guiersi that occurs in southern Mauritania and Senegal. The first conclusion is that the measurements and moult strategy of Moroccan reed warblers fall between those of European and African Reed Warblers, that they are also intermediate in terms of wing formula but due to the absence of an emargination on p4 look closer to European, and that in terms of plumage and bare parts colour they appear more like African. Further research will clarify the phylogeny of Moroccan reed warbler."​