State of the UK’s Birds 2012 is full of interesting information.
I was struck by the analysis of the number and weight of birds in the UK as a whole.
In the early 1970s there were about 105 million pairs of birds in the UK – now there are around 83 million. More than a fifth of UK birds have disappeared from our lives since my teenage years. We can’t call that progress.
Lots of those lost birds are little birds – the sparrows, buntings, finches etc.
Such species (basically passerines) make up about 67 million of the 83 million pairs of birds that we still have flying around the place. But if you look at things in a different way, by weight, then those 67 million little birds only add up to 6.7 thousand tonnes of bird mass out of a total of about 25 thousand tonnes in all. The big birds are so much bigger than the little birds that even though they make up only c20% of the numbers they make up 75% of the weight. It’s a new perspective.
And here’s another one. Non-native species number about 2.5 million pairs out of the 83 million total, but they make up around 6 thousand of the 25 thousand tonnes of wild bird mass. I guess Canada geese and pheasants make up a large part of these numbers and these weights of non-native species.
These figures must be based on assuming that there is a breeding population of, I think 1-2million pairs of pheasants in the UK. So it doesn’t take account of the 35 million released for shooting each year, of the 9 million or so red-legged partridges either. We are weighed down with introduced gamebirds. You’d have to think they make a difference to something ecological just by weight of numbers, wouldn’t you?