THE SWIFT, which is traditionally the last migratory bird to arrive in Ireland for the breeding season and the first to leave, is still being seen along the south coast.
According to Oran O'Sullivan of Birdwatch Ireland, the swift, which is often mistaken as a large swallow, should have departed for warmer climes much earlier in August.
"However, we are receiving reports that there are many birds still here, even though we would have expected them to have left by now," he said.
He said the swift arrives in Ireland in May after the swallows and housemartins and leaves in mid-August, but this is the second year that their departure has been delayed. The bird, he said, produces one brood in a breeding season and lays two or three eggs, so it is unlikely its departure is being delayed by a second brood.
"Bird migratory patterns are useful to look at when seeking evidence of climate change and we may be looking at that," he said.
"When we see blackbirds nesting in February, we have to think about what is going on.
"We do know that it is still fairly warm here and there is a lot of insect life around which would support birds who might normally leave when such feed sources dry up. It is possible that this is the case with the swift," Mr O'Sullivan added.
He said that Birdwatch Ireland had received a number of reports of visiting hobby falcons to the south of the country.
These birds, he said, which are about the size of a kestrel, were migratory and until recently, were very rare summer visitors to Ireland.
"They are now coming here and one of their main sources of food is dragonflies which are increasing in number here annually," he said.
"If fact we have found two new species of dragonfly here recently and this too may be a sign of climate change," Mr O'Sullivan added.