PIED WAGTAIL (_Motacilla lugubris_).--This familiar British species occurs rarely in S. Spain--we have but four records, all in winter. In the reverse, the WHITE WAGTAIL (_M. alba_) abounds--ploughed lands sometimes look _grey_ with it; and it is here, in winter, as tame and familiar as one sees it in Norway and Iceland in summer. Yet midway between the two, _i.e._ in the British Isles, we have seen it but thrice! There it may indeed be termed a "rare bird." The explanation seems to be that (like the two southern wheatears) these two wagtails are not specifically distinct, but merely a dimorphic form. This year (June 1910) we found the white wagtail breeding commonly in North Estremadura. During a northerly hurricane on February 7, 1903, we observed an assemblage of many hundreds of white wagtails on the barren sand-dunes of Majada Real--a second crowd, as numerous, a mile away. Both were migrating bands arrested by the gale. This is merely one example out of scores that have come under our notice of the magical apparition of birds from the clouds, caused by a sudden change of wind. Specially notable, besides wagtails, are swallows, wheatears, pipits and larks. The GREY WAGTAIL (_M. melanope_), though occasionally seen in winter, is most conspicuous about mid-February, when it passes several days on our lawn at Jerez. It has not then acquired the black throat of spring; but two months later we have found it nesting on mountain-burns of the sierras--precisely such situations as it frequents among the Northumbrian moors. The YELLOW WAGTAIL (_M. flava_; the Continental form, _cinereocapilla_) appears on the lawn a week or so after the grey species has disappeared; but this remains throughout the spring, nesting in wet meadows and marshes, laying during the last week of April. The British form (_M. raii_) also occurs during spring, but rarely and on passage only, none remaining to nest. RESTRICTED DISTRIBUTION ROOK (_Corvus frugilegus_).--There is a certain limited stretch--say a league or so, on the foreshores of the marisma--whither each winter come a few scores of rooks. At that one spot, and nowhere else within our knowledge, are rooks to be found in southern Spain. MAGPIE (_Pica caudata_).--On the western bank of Guadalquivir this bird abounds to a degree we have seen surpassed nowhere else on earth. But cross that river, and never another magpie will you see for a hundred miles to the eastward. For it the lower Bætis marks a frontier. Over the rest of Spain its distribution is normal and regular. A similar remark would almost hold good of the Jackdaw (_Corvus monedula_). The AZURE-WINGED MAGPIE (_Cyanopica cooki_) abounds in central Spain and in the Sierra Moréna. But its southern range stops dead at the little village of Coria del Rio just below Sevilla. 'Tis but a few miles beyond, yet in Doñana we have never seen so much as a straggler. The Azure-wing does not straggle.