The Cuckoo Cuculus canorus has a foul popularity due to its behavior of laying its eggs on the nests of different birds, who then elevate their younger. However in south-west Europe there’s a chook that kicks out the sitting tenants and takes over the nest altogether. The White-rumped Swift Apus caffer, a tropical African breeding species, was solely found breeding in Europe within the Nineteen Sixties. This was in southern Spain, close to the city of Zahara de los Atunes in Cádiz Province, on the northern shore of the Strait of Gibraltar. On the time the chook was confused with the Little Swift Apus affinis, an identical species, additionally with a white rump. The confusion was comprehensible. Little Swifts breed in Tangier, just some kilometres on the opposite facet of the Strait so it could have been logical to count on these to have made the brief sea crossing into Europe.
The White-rumped Swift, alternatively, had a sub-Saharan distribution so no one suspected it to have made the soar throughout the Sahara. If its arrival was shrouded and mysterious, its nesting behaviour is actually a cloak and dagger affair. White-rumped Swifts arrive in April and search out Purple-rumped Swallows Cecropis daurica. They’ve additionally arrived from tropical African wintering grounds and, by that point, are busy repairing outdated nests. These are mud constructions, simply identifiable by a protracted entrance tunnel, which can be positioned on the roofs of culverts, below bridges and related buildings. The swifts arrive, search the swallows out, discover their nests and evict the tenants! They then settle of their newly acquired house, lay their eggs and lift their brood. How are you going to inform if a Purple-rumped Swallow’s nest has been taken over? Straightforward. The swifts line the doorway with white feathers – it’s the clear signal that that is now property of White-rumped Swifts and it might even be a method of displaying a possible mate that this little bit of actual property has an proprietor.
The inhabitants of White-rumped Swifts has expanded slowly, in numbers and geography, some now breeding as far north as Extremadura in central Spain, however the stronghold stays the Strait of Gibraltar. Current estimates counsel that the inhabitants could also be of the order of 200 pairs. That’s all the European inhabitants, tucked away in south-western Iberia.
What triggered this growth from Africa? I’ve a hunch that it was the Purple-rumped Swallows themselves. Howard Irby, writing on the finish of the nineteenth Century stated that the Purple-rumped Swallow had been recorded from Malaga and Valencia. In different phrases, it was a uncommon chook. These days, Purple-rumped Swallows are considerable and widespread breeding birds so there should have been an arrival and growth through the twentieth Century. The swifts would have adopted. They have been first detected within the Nineteen Sixties however who is aware of how lengthy that they had been there earlier than that?
What of the Little Swift? Curiously, in addition they breed in Iberia at present. They have been first detected in Malaga in 1981 and within the Strait of Gibraltar space in 1983 and are slowly spreading northwards. The inhabitants is small, maybe not more than 200 or so pairs, and the principle focus is, once more, in Cadiz Province, SW Spain. They breed in colonies, typically near human habitation.
I’m fortunate to stay shut to those two gems and in part of Europe that boasts no fewer than 5 breeding species of swift!