That is peak time for the migration of Western Marsh Harriers (Circus aeruginosus) throughout the Strait of Gibraltar. These birds are heading south-west, lots of them crossing the Sahara Desert to wintering grounds in West Africa. Others will spend the winter months north of the desert, in Morocco and within the Iberian Peninsula, the place they be part of the native residents. These migrants are basically western and central European in origin and others are Scandinavian. As with different raptors, the northernmost ones are essentially the most extremely migratory, they usually leap frog the residents to winter south of them.
Not like the bigger, broad-winged, raptors, Marsh Harriers have lengthy and slim wings (with excessive facet ratio) they usually depend on powered, flapping, flight to get them throughout boundaries, similar to the ocean. For that reason, they don’t mixture at slim sea crossings to the extent that eagles and buzzards, for instance, do. All the identical, good numbers are seen on the Strait of Gibraltar, though these are measured within the a whole lot, not 1000’s as can be the case with the species that rely on the slim sea crossing.
A broad estimate of the European inhabitants places it at someplace between 100 and 200 thousand pairs, with an obvious rising development within the east. The most important populations are within the north-east, in Russia, Belarus and Ukraine, with good numbers in Poland and Germany. These are largely migratory and can embrace birds that fly south-west in direction of Gibraltar. An estimate of the, smaller, Spanish inhabitants places it at round 800-900 pairs.
Other than seeing them crossing the Strait of Gibraltar in spring and autumn, I recurrently see Marsh Harriers in wintering websites near Gibraltar. The outdated lake of La Janda and the Guadalquivir marshes are favorite haunts. If I wish to {photograph} them, and hides are important for these skittish birds, then the location of the Laguna de El Taray in central Spain is my primary alternative. Right here, hides are partly dug into the bottom, providing nice views, and there are many Marsh Harriers all yr. The truth is, on this non-public property holds no fewer than sixty breeding pairs of Marsh Harriers!
So, even right here in Gibraltar the place I’m spoilt for alternative of huge raptors of various species, and in large numbers, the harriers are amongst my favourites. At this time, I’ve highlighted Marsh Harrier however passage additionally contains Montagu’s Harrier (Circus pygargus), which I’ll write about on one other event. To those we must always add a small passage of Hen Harrier (Circus cyaneus), some reaching Morocco and others wintering north of the Strait, and Pallid Harrier (Circus macrourus). The latter is the scarcest however people are recurrently seen at La Janda on passage and in winter, and certainly additionally crossing the Strait of Gibraltar. These birds could signify the latest westward extension of this species’ breeding vary.
