Lazy or smart?

This is peculiar:

Growing numbers of migratory birds are too lazy to fly all the way to Africa for the winter and are staying in Britain.
Unprecedented numbers of warblers, blackcaps and chiffchaffs shirked the flight to warmer climes last year and even more are expected to stay this winter. Most surprising is the number of species of warblers that can now be found in Britain in the coldest months, according to a survey by the British Trust for Ornithology (BTO).
Greg Conway, who organised the survey for the trust, said: "It's as if they're saying, 'I can't be bothered to go abroad this year, dear — let's stay here'. They're too lazy to migrate to Africa."

Apparently this has little to do with warmer winters in Europe, which are still too cold for them. It seems that the birds migrate from Germany and have discovered that they get the best breeding grounds when they fly back (in the spring) if they spend the winter in the UK instead of flying all the way to Africa: first come, first served.