WITH its distinctive splashes of blue, yellow, white and green, the blue tit is one of the more colourful - to say nothing of welcome - visitors to our garden each year.

It's an intriguing little creature, as BBC Radio's Tweet of the Day series reminded us last year: though the male and female blue tits look identical, they can clearly tell each other apart. The male's blue crown feathers reflect ultra-violet light, depending on his fitness and status - an attribute that may help the females to choose a mate.

The blue tit was also known for shredding the foil tops of doorstep milk bottles in search of cream.

New research, however, suggests that a dreadful breeding season may lead to urban populations of blue tits being somewhat reduced this summer.

A study by Scottish scientists indicates that 90 per cent of blue tits nests in urban areas failed to produce a single surviving chick. Research was carried out in Glasgow but one of the researchers, Dr Davide Dominoni, says he expects there to have been a similar situation in other cities. More worrying is the fact that the cause remains a mystery - for now, at least. Some theories are, however, being pecked at. We can only hope that the cause can be identified. Our cities need these vividly-coloured little birds.