IDENTIFICATION

Melodious & Western Olivaceous Warblers
	In September 2002 the BOU (British Ornithologist's Union) recommended that the Olivaceous Warbler (hippolais pallida) should be splitted in two different species, bearing in mind, among other reasons, its geographical distribution. In that case we had to separate an Eastern species of a Western one, this last would be monotypical with a breeding range extending Iberian Peninsula and Northwest Africa. The iberian birds would belong of course to the Western species having hippolais opaca as latin name. The Eastern species would be polytypical with the nominal subspecies pallida and three more recognized, reiseri, laeneni and elaeica. Melodious Warbler Olivaceous Warbler
Running the line of our previous articles in this section it had been more appropriate to see the differences between these two species of Olivaceous Warblers (Eastern and Western), or even the shared features of Icterine and Melodious Warblers, both very similar species, bearing in mind that some cases of hybridation have been recorded as well. But our main intention was to compare the two hippolais species more common and widespread in Spain, and therefore, with more chances to see in the field.      In fact we could say that both species (Melodious and Olivaceous) are fairly different to the exception of some Melodious Warblers, mainly young birds, duller than usual. Let us show you the main features of these two species to see how of similar they are when you finish to read this article.      The Melodious Warbler (hippolais polyglotta) is the most widespread hippolais warbler in Spain, showing grayish-green upperparts and wings, and lack of the typical pale wing panel of Icterine Warbler (hippolais icterina). Like the Olivaceous Warbler, it has a short primary projection, being somewhat longer in the Icterine. In some pale birds (nearly 20% of the birds of the Iberian Peninsula) the upperparts are less dark, whereas the underbody feathers are boldly yellow. Juveniles present on average a brownish and darker mantle with underparts white-yellowish or even cream color in most of the feathers, although they always show a light yellow hue in throat and breast as minimum. The pattern of the rounded head has a yellowish eye-stripe and eye-ring, in contrast more with the dark crown than the greenish pale ear-coverts.      Song long and speed with some fragments of mimicry, imitating other species. In spite to be present in most of the country tends to be rare in montainous areas and in Northern latitudes, being usually absent over the 1,000 meters.      Breeds in open and shrubbery areas with some scattered trees. More common in riverine vegetation. Most of the birds reach the Iberian Peninsula in the second fortnight of April, and return to Africa mainly in August, remaining some birds till October.      On the other hand, the Western Olivaceous Warbler (hippolais opaca) has the upperparts of a dull grey to brown, with very pale or dusky white below, having both sides of the breast and belly buffish. Western Olivaceous Warblers in addition show a darker crown than the rest of the subspecies of the Eastern hippolais pallida. It never has yellowish feathers. Due to its pale colors can be overlooked with the Garden Warbler (sylvia borin), but if we paid more attention to the shape and length of the bill and head profile we will solve our doubts.      This head that we mentioned presents a pale, but dull, supercilium which extends beyond the eye in very few cases and always with fresh plumage, besides showing an evident eye-ring. This is surely the hippolais less boldly marked in the face. The color of the legs can change depending on the age.      The song vaguely resembles to the Reed Warbler but with shorter fragments and much more repeated.      To be a "subsaharian" migrat the first birds don't reach the Iberian Peninsula till the second fortnight of May, returning to their wintering areas throughout August and September. In Spain breeds in the South third and along the Mediterranean coast, comming inland through the Ebro valley and then reaching Navarra. It has preference to the African Tamarisks (tamarix africana) join the water, although it's also present in river thickets and irrigation fields.      To compare both species it would be necessary to start saying that Olivaceous Warbler is slightly bigger than Melodious, although overlaps are frequent in some smaller Olivaceous.      The most streaking features to separate these two hippolais are the shape and bill pattern, in Olivaceous very pale and yellowish seen from below, and much more longer and wide, which continues towards a forehead and crown flater than in Melodious, giving an expression of "big-nose". As far as the face pattern is concerned the dark bridal of Olivaceous, absent in Melodious, would be a very good clue.      Although both species, already commented above, have relatively short wings, the color and look of the bird could be the most useful feature, to the exception of some pale Melodious in juvenile plumage over all. But after a more careful examination the typical yellowish hue of Melodious in throat and breast will be surely seen. Texts: Santiago Villa Illustrations: Juan Varela Photographs: P. Dubois and Birdguides.com Spainbirds ® 2004