THERE is a new sound in some gardens and parks this weekend. It is a wheezy note rather like a long, fruity kiss, and it comes from the tops of tall trees. It is a greenfinch trying out his first spring calls.
The greenfinch flocks have mostly been roaming around the countryside so far this winter, looking for burdock seeds, rosehips and dried-up old blackberries. They are doing better than some related birds, such as the yellowhammer, with their numbers up slightly, and they have also been expanding their range northwards. Two or three have been seen recently for the first time in Iceland.
Now they are beginning to settle down in the places where they will nest. They are conspicuous birds, colourful and noisy. The plumage of the males is steadily getting brighter as the length of the days increases, and they will soon be a vivid green, with a gold wing-bar and gold edges to their tail. Besides this spring note, they have a rattling twitter when they fly. They sometimes sit in the treetops twittering rather less emphatically, as if they were revving up before going.
They also have a proper song which will soon be heard. It starts off with a run of notes rather similar to the twitter, then bursts into a rollicking stream of more plummy notes, and can be heard both when they are perching and flying. It is very distinctive, though a year or two ago a chaffinch was heard singing exactly like a greenfinch.
The greenfinches are now pairing up without leaving their flocks. A male will chase a female, then court her by drooping his wings, spreading his tail, and trying to nibble at her beak. Then he may try another. In this way the pairs slowly sort themselves out.
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As nesting time gets closer, the rather solid, sensible- looking male greenfinches suddenly go mad. They start flying high in the sky, singing, rocking from side to side, now beating their wings in a curious slow way, now taking long glides. No one knows quite why. Display flights are used by some birds to defend their territory, but greenfinches hardly have a territory, usually nesting near each other in a loose colony. So a completely opposite explanation has been suggested: the displays attract new birds into the colony, so that they become a stronger flock when they all fly off together looking for food.
derwent.may@thetimes.co.uk
WHAT TO LOOK OUT FOR
Birders Look out for flying herons carrying nesting material to the local heronry.
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Twitchers A drake wood duck at Belfast Lough RSPB Reserve, Co Down; a Coues’s arctic redpoll at Shell Ness, Isle of Sheppey, Kent; female lesser scaup at Caerlaverock Wildfowl & Wetlands Trust, Dumfries & Galloway.
Details from Birdline, 0906 8700222 (60p a min) www.birdingworld.co.uk www.rspb.org.uk