Quarry: the sacred ibis
Threskiornis aethiopicus
This striking wader was revered by the ancient Egyptians but its colonisation of parts of Europe has given conservationists more worldly concerns, says Charles Smith-Jones
This month’s quarry species may come as something of a surprise. It is a bird that we more usually associate with the warmer parts of central and southern Africa but, according to some, it may be on its way to our shores. And it could have a devastating effect on UK wildlife if it arrives and thrives. For this reason it was included on the latest general licence issued specifically for the conservation of endangered wild birds.
The sacred ibis does not stand as tall as our native grey heron but is a heavier bird with a much greater wingspan. It is impossible to mistake the two species for each other, or indeed any of the smaller egrets. Most of its body is covered with white feathers, with blue-black plumes that fall to form a tuft that covers the short tail and wing tips. The legs, neck, head and thick downcurved bill are a dull black. In flight, the broad white wings have a visible black border along the feather tips along the entire rear edge. Juvenile birds have more mottled black and white heads and necks.
Mummified
Revered by the ancient Egyptians – hence the name – the sacred ibis were mummified in their thousands every year and placed in tombs or buried by pilgrims as an offering to the god Thoth. Such was the demand for birds that special ibis breeding farms known as ibiotropheia were established. Today, though, the sacred ibis is seldom seen in Egypt and only then as a rare vagrant.
Although it is mainly an African bird, there are breeding populations closer to Britain than you may think. Escapes from collections led to it becoming established along the Atlantic coast of France since the early 1990s, and the French breeding population alone was estimated at some 1,100 pairs by 2005. Since then an eradication programme has culled over 8,000 sacred ibises between 2007 and 2016, reducing numbers to a few hundred by 2017.
Eradication
It is generally accepted, however, that as the birds became more wary – and the time and cost involved in culling them increased – full eradication may never be achieved. Elsewhere, they have also bred successfully in Spain and the Netherlands but have not flourished, although they seem to be doing well in Italy and there seems to be no coordinated efforts to halt their spread.
It is the sacred ibis’s feeding habits that are the cause for such alarm for us here in Britain, along with the devastating effects that this bird will have on our native species should it
decide to set up residence on this side of the English Channel. Wading through shallow wetlands or dryer ground, it feeds voraciously on pretty much whatever it can swallow and its diet has been known to include pelican eggs, cormorant nestlings and even the eggs of the Nile crocodile in Africa.
Conservationists on the Continent have already witnessed the effects of scared ibis predation on endangered native species. In western France, the sacred ibis has been witnessed driving sandwich terns off their nests before eating their eggs. On at least three occasions, colonies of the more vulnerable black and whiskered terns have been entirely destroyed.
Other species whose nests have been similarly predated include the lapwing, black-winged stilt, various species of duck and cattle egrets. The sacred ibis has also had serious effects on local populations of amphibians such as newts.
It is feared that the eggs and young of sensitive ground-nesting birds will be especially vulnerable should it arrive here. As a result the general licence has included it to ensure that Britain is not vulnerable to similar depredations.
Conditions here are similar to those in France, and southern parts of the country are thought to be especially vulnerable. Quite apart from predation they could potentially carry diseases damaging to native birds, the poultry industry and even to humans. The lessons from France have underlined the difficulty and cost involved in controlling an established population, so shooters may yet have to play a part in keeping this unwelcome visitor out of the UK.