ONE swallow might not make a summer, or even an Irish spring.
Birds from sub-Saharan Africa have decided not to migrate to Ireland so far this year – because it's too cold.
At least three types of birds that normally arrive here at this time are staying away in large numbers, according to Niall Hatch of Birdwatch Ireland.
Other feathered residents here are still feeding at garden bird tables and haven't started breeding yet because of the unseasonal cold snap, it has also been discovered.
The birds staying in hot Africa for the time being include the sand martin, the wheatear and siskin, a member of the finch family.
Birdwatchers are also being asked to look out for swifts, cuckoos and swallows, which should also be here in large numbers by now.
Birdwatch has set up a special website, springalive.net for members of the public or birdwatchers, also known as 'twitchers' to alert them to the first arrivals.
So far, just 16 swallows, one swift, five cuckoos and one white stork have been recorded on the site.
Birds travel thousands of kilometres every year to spend the spring and summer here, before returning to Africa.
Swallows, familiar here, fly north to Europe in springtime to breed, nest and raise their young.
European birds spend the winter in the western part of Africa.
While the birds might not be aware of the precise climate in Ireland, they know temperatures are way down across much of the route they take to get here.
Mr Hatch said the "seriously cold" weather was having an effect on birds.
"There are definitely far fewer than normal," he told the Irish Independent.
The cold weather also meant that many birds were still feeding on seeds and nuts left out by householders, and were being affected by the lack of insects due to the cold.
Mr Hatch said: "We would encourage people to continue to feed birds in the garden, and you can get tips at birdwatchireland.ie."
He also appealed to members of the public to notify the springalive.net website if they spotted any swifts, cuckoos or swallows in their area.
"We need people to tell us when they see these birds returning," he said.