|Glossy Ibis, Ebro delta|
Only a few years ago, news of a Glossy Ibis Plegadis falcinellus in the UK would result in a mass of birders descending on the area. These days they are a scarce but regular presence in wetlands, especially in England, and there has even been at least one (unsuccessful) breeding attempt. Even in December several are still present in the country. Further south much larger flocks can be found in Spain and the south of France, but the bulk of the European population is in Ukraine and Romania. Further afield this species is one of the most widespread of the worlds’ ibises, being found from Africa to Australia. Crossing the Atlantic around 150 years ago, in the same way as Cattle Egrets, they established themselves in Central America and have since spread both north and south, and have bred as far north as Canada.
|Glossy Ibis in breeding plumage|
It is possible however that the northward movement of the European birds may perhaps be a recolonization rather than an entirely new event. Both egrets (probably Little Egrets) and Night Herons were known in pre-Little Ice Age England, and it is quite likely that other southern herons and wetland birds were also present. The increasing warming of the British climate and increasingly effective creation of wetland areas in the south of England is encouraging colonisation of many bird species whose current range is further south.
|Northern Bald Ibis|
In Europe, for all practical purposes any ibis will be Glossy Ibis. The only other to be found at all is the Northern Bald Ibis Geronticus eremetica, a Critically Endangered species whose only viable wild population is in Morocco. Even there the total population is under 600 birds including juveniles. There are however attempts to reintroduce birds to parts of their former range, including southern Spain. These are proving quite successful, with 23 pairs raising 25 chicks in 2014.
The reason for the great difference in the success of the two species lies in their different ecological requirements. Glossy Ibises are generalist wetland birds, feeding on invertebrates, small fish, frogs, and occasional small mammals. Bald Ibises are steppe specialists, feeding largely on beetles and lizards. Their breeding biology is also different, with Glossy Ibises nesting in trees near water, while Bald Ibises nest on cliff ledges. If not hunted neither species is shy around people – there are historical records of Northern Bald Ibises nesting on castle ledges for example – but pesticide pollution is a threat to both.
For more on the Northern Bald Ibis, see here: http://northernbaldibis.blogspot.co.uk
(Images my own, from Wikipedia)