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)
Think you've overlooked the substantial feral population of Sacred Ibis when saying any ibis in Europe is likely to be a Glossy.
ReplyDeleteThanks for the reminder. I have seen them on the Canaries but I had not realised the size of the French population, or that they are so close to the UK. Given their scavenging habits I would not be surprised if the population did not continue to grow.
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