Every autumn, the most impressive wildlife spectacle plays out over a narrow strip of water that separates two continents. Over the Strait of Gibraltar, where Europe and Africa draw nearest to each other, tens of thousands of raptors gather every year, flying southward in order to get through 14 kilometers of a narrow channel, where it’s safe enough to make the risky crossing. Among these impressive birds is the Short-toed Snake Eagle, whose members were seen recently above the Strait in numbers that had never been observed before.
This unusual occurrence was reported by the team from Birding The Strait, a birding tour guide service based in Tarifa, which watches the raptor’s migration every autumn. Among the dozens of regularly colored individuals that pass through the Strait of Gibraltar every autumn, there was one juvenile Short-toed Snake Eagle whose appearance could hardly have been called regular. Almost completely white, it was a unique bird, like none other, as they say, that the team has ever observed. It flew over the Strait between the towns of Tarifa and Algeciras for several days, surrounded by dozens of regularly colored members of its species, and apparently crossed to Africa, using a brief period of favorable weather conditions. The photograph that caught this amazing moment belongs to Fernando Portillo de Cea and is likely to become the only evidence that we ever will have about this bird.
In order to appreciate the significance of the sight, it is necessary to describe what the Short-toed Snake Eagle usually looks like. This is a large raptor whose life is devoted to one single purpose: hunting for snakes, including venomous vipers that other predators usually avoid; it kills the snakes with accurate strikes to the head and eats them whole right in the air. The plumage of the snake eagle is not homogeneous, but contrasting, its light belly contrasts with greyish-brown backside; its dark hood and banded tail can be seen when it flies. An almost completely white juvenile of this species is not a color variant but a real rarity. A plumage condition, occurring so rarely in wild raptors that birders usually observe such a phenomenon for decades.
As for timing of the phenomenon, it was no coincidence either. Late September and early October constitute the peak passage time for the Short-toed Snake Eagles, who fly from their breeding grounds in Europe toward wintering areas in the Sahel, south of the Sahara. The migration is dominated by juvenile birds making their very first crossing, which is part of what made this particular sighting so improbable. Among thousands of young eagles testing the same stretch of sky for the first time, exactly one of them happened to be unlike anything else in the sky that week.
It’s a reminder of something birders already know but rarely get proof of. That somewhere in every massive, predictable migration, there’s room for the genuinely unrepeatable. The bird crossed, the window closed, and whatever happens to it now continues somewhere over West Africa, out of sight. But for a few days in Tarifa, hundreds of birders got to watch something that looked less like a bird and more like a rumor come briefly, improbably true.
