In the past, most species have had time to adapt to natural fluctuations in the climate, which usually occurred gradually over several decades or even centuries. The rapidity of human-induced global warming has thrown the world of birds into chaos. Habitats are affected, long-distance migration is disrupted by more severe (and more frequent) weather events and, in some cases, breeding cycles are now out of sync with the insect foods on which chicks depend. Niche specialists, including many of our most iconic birds, are most vulnerable and threatened with regional, national or even global extinction during this century.

In Europe, the first obvious effect of climate change was the northward spread of southern species, like egrets and bee-eaters. Iberian specialists, like black-shouldered kites and the endemic azure-winged magpie, are now also occurring north of their former ranges. It is not too surprising, therefore, that the oceanic barrier between North Africa and Iberia has not deterred a parallel shift of Maghreb residents into similar arid-zone habitats in the Algarve and southern Spain as their traditional haunts become more desertified.

In my seven years in southwest Algarve, I have witnessed an annual increase in the occurrences of North African species either new to Europe or previously regarded as ‘vagrants’ (extreme rarities). These include the ill-named desert lark, which prefers bushy habitats in hilly areas, Moussier’s redstarts, grey shrikes of two different Saharan races, Barbary falcons, common bulbuls, and even fulvous babblers, previously found only to the south of the Atlas mountains in Morocco. The red-tailed ‘Atlas’ Buzzard (also badly named as it occurs right across North Africa into the Middle East) is already breeding in Iberia. In just the last year I can add the laughing dove, the tiny, long-tailed Namaqua dove, and Sudan golden sparrow to the list of potential colonists.


Causes

If the causes of many of these arrivals can be understood, with sand-laden, Saharan winds from the southeast aiding the process, the situation in the oceans is more chaotic. I monitor seabird movements off Salema, only about 20 km east of the southwestern tip of the European land mass, Cape St. Vincent. The huge triangle of the sea, funnelling into the Straits of Gibraltar, between the North African and southern Iberian coasts, acts as a ‘capture zone’ for seabirds moving north from Africa or driven east from the Atlantic and the Gulf Stream, which draws some Caribbean breeders, like boobies and tropicbirds, up to the north-east. I am now seeing these frequently and have also discovered that Audubon’s Shearwater, which breeds on the Cape Verde Islands but never before recorded in European waters, is a regular winter visitor to these food-rich seas.

More dramatically, albatrosses, giant petrels, and other seabirds from the South Atlantic are now appearing offshore. In the past, it was assumed the doldrums near the Equator were responsible for preventing these large, gliding species from reaching the northern hemisphere. So what’s changed? When the early Portuguese navigators were struggling to find ‘the end of Africa’ (and a lucrative route to the Spice Islands) they were repeatedly thwarted by southerly winds off the coast of southern Africa. Satellite weather maps now show these same prevailing winds to be not only stronger (in line with global warming predictions) but also more extensive, even reaching the Gulf of Guinea. This takes the doldrums out of the equation. I could never have imagined that I would be seeing my first Wandering Albatross off the Portuguese coast, but four different species have now occurred locally along with the first Atlantic Petrels for Europe and multiple giant petrels and south polar skuas.

In the north, the melting of the Arctic ice has resulted in another suite of possibilities, as the North-West Passage is now allowing migratory seabirds from the Pacific to enter the North Atlantic. The west coast of Portugal is the more likely recipient of these strays but off Salema I have already encountered three species: the first pink-footed shearwater for Europe, a short-tailed shearwater, and a tufted puffin, a species which reaches similar latitudes in winter off the Californian and Mexican coasts.

Birdwatching has never been more exciting, but the enjoyment of seeing new and rare species must be tempered by the knowledge that these ‘riches’ are the result of bird populations under extreme stress. Scientists are acknowledging that we are directly responsible for the Earth’s latest extinction event. It is to be hoped that a major catastrophe can be avoided, but I see little sign of any willingness by Homo sapiens to rein in its globe-trotting, consumerist lifestyle.

by Alan Vittery