THIS has been a pretty miserable summer in the British countryside so herewith the good news: things are getting better for our birdlife, according to the latest survey from the British Trust for Ornithology.

The BTO, with the help of thousands of volunteers, has been tracking the ups and downs of our bird populations for almost 40 years - and for most of that time, the news has been pretty gloomy, thanks to loss of habitat, new building development and new farming methods.

The results of the latest survey, carried out last year, were published today and show a marked improvement in the numbers of many species with only one exception - the common blue tit, down by 6%.

In contrast, some species showed huge improvements: tawny owl up 33%; mistle thrush (31%); red-legged partridge (27%);chiffchaff (25%) and whitethroat (20%).

Of particular note was the growth in numbers of some of our most common birds which, for reasons largely unknown, had been suffering such a decline that they had been placed on the list of "Conservation concern" species.

They include the song thrush (now up 17%), the dunnock (10%) and even the humble blackbird (6%).

"A good year is good news for British birds," says the BTO, which goes on in more detail to list the progress of what was once one of our most persecuted birds, the heron.

The "happy heron is still on high," it records cheerfully, with some 10,000 nesting pairs, many of which live in long-standing colonies which can be as much as 70 years old.

The heron was once shot out of hand by water bailiffs and gamekeepers because of the young trout and salmon parr they undoubtedly eat (although eels are a favourite morsel, too). Now, much more enlightened attitudes hold sway on most sporting estates and this has helped the heron's re-emergence as a major species.

However, the most likely cause of the heron boom is also man-made: global warming! The bird is exceptionally vulnerable to hard winters, with its fish prey out of reach in frozen ponds and streams and other food species, like frogs, in hibernation.

We have not had a really severe winter now for several years and many more birds have survived than in the recent past. So, for the happy heron at least, global warming is a cloud with a silver lining.

The BTO is looking for volunteers to join their heron watch team. Anyone interested should contact John Marchant - john.marchant@bto.org