“Return” of the White-tailed Eagle to southern Iberia?

I attended a recent workshop which was being transmitted online. I was particularly interested to hear what was going to be said about a project which aims to release White-tailed Eagles (Haliaeetus albicilla) in southern Spain. Note that I say release and not re-introduce. The online listeners were invited to ask questions, so I did. Frustratingly, they were glossed over and my name, as author of the questions which I was obliged to give, was never mentioned. Instead, the comments about the validity of the claim for re-introduction went along the lines of: “well there are different opinions on the subject” and such like. Well, they are not opinions, they are facts as I will now enumerate.

The historical evidence cited was a quote from an article “Notes on the Birds of the Straits of Gibraltar” the journal Ibis of 1879, in which the respected ornithologist Howard Irby stated “Mr. Stark, during the first week in May 1876, found a nest of the White-tailed Eagle on a cliff on the coast. I refrain from mentioning the exact locality for obvious reasons. The nest contained one young bird nearly able to fly.” That was it. No other historical evidence was presented at the workshop. Some of you may think that this is enough evidence to justify a re-introduction but note the following. Irby published the second edition of his book “The Ornithology of the Straits of Gibraltar” in 1895, that is sixteen years after the article. Irby’s book is thorough and detailed, a real reference work for those of us working in the region. Turn to the page on White-tailed Eagle and this reference is not there! In fact, Irby provides no evidence of this bird having bred in the region. Irby also avoids other references which he had cited previously from Mr Stark – in those sixteen years he had lost confidence on the veracity of these claims. Knowing how thorough he was, I am sure that he visited Stark’s cliff on the coast and found the claim not to be true but, being a courteous gentleman, chose to remain silent in the later work, rather than slur Mr Stark’s reputation.

The rest of the evidence presented at the workshop was based on fossil and sub-fossil material from caves in the Iberian Peninsula. Now that’s a subject which I know well! I’ve worked on this material for over thirty years and I know the sites. In what was adding insult to injury, I had to endure references being made to recent discoveries of White-tailed Eagle subfossils from Gibraltar’s caves – my own work! It was like hearing the devil quoting out of the bible! I sent further comments but these were not taken up either so I will say them here.

You cannot use subfossil bird material to argue for species re-introductions. These bones reflect the presence of these species thousands, even tens of thousands of years ago. In the case of the Gibraltar White-tailed Eagles, they go in some cases as far back as 100 thousand years ago! The remains are found alongside those of Snowy Owls (Bubo scandiacus), Little Auks (Alle alle) and Steller’s Eiders (Polysticta stelleri) and, yes, they were around alongside the Neanderthals! We don’t even know if these were breeding birds or perhaps just winterers. So, if you are going to use this kind of evidence for “re-introductions”, you might as well “re-introduce” Snowy Owls, or perhaps even Neanderthals to the south of the Iberian Peninsula!

Joking aside, there is absolutely no evidence in support of the presence of breeding of White-tailed Eagles in southern Iberia in historical times and the evidence from prehistory is inconclusive. If this project goes forward, people will have to understand that it is not a re-introduction. It establishes a dangerous precedent which might lead us to creating zoos in the wild, of species that don’t belong, with unknown ecological implications which could result.