One of the sounds I dread when in the house or garden is the thud as a bird strikes a window. Even if they bounce off, the lasting damage of being stunned cannot be good for their chances of survival, and every year, I expect to find maybe two or three birds killed outright by the impact. Who knows how many more struggled off under a bush to die or are picked up by a Fox before I notice it.

There are about  25 million households across the country, plus millions more greenhouses and windowed offices, not to mention the fad of putting mirrors in gardens. Add up that kind of birdstrike over the country and maybe 100 million birds or so are wounded or killed in that way each year in the UK. That is just my back-of-fag-packet calculation, but it is certainly a lot of birds. A lot of mainly garden birds.

The reason that birds fly into windows is of course because they see - and focus on - the reflection, which if the room behind is dark can effectively turn the window into a mirror. My measures to date to combat birdstrike on my house include closing the curtains when I'm out, so that the pale reverse of the curtain material reduces the mirroring effect. But the most effective thing has been sticking black raptor silhouettes on the outside of many of my windows, including the greenhouse. (On the inside of a window, silhouettes don't work whenever the window is acting like a mirror).

But despite doing all this, there are still large areas of glass in the house without stickers, and they show all the tell-tale signs that birds are striking the glass.

Those that create the most lasting impression are members of the pigeon family. They have specialised feathers called powder down, which they use to help clean and lubricate their plumage. When a pigeon hits a window, the impact releases the powder, creating an incredible chalky ghost-image of the bird.

Here you can see one such strike on my bedroom window. You can see the large area of breast feathers, with the two wings held up either side as, at the last moment, the bird tried to avoid impact.

So if I am to combat this, does it mean that I will have to put black stickers on the outside of all my windows? Like most people, I love looking out into the garden unobstructed, so can birdstrike be reduced without obscuring the view?

So I thought I'd try for the first time the stickers ('decals') that are see-through to the human eye but contain ultraviolet pigments that are meant to be visible to birds.

You have to transfer them using water, and mine didn't exactly go onto the window without a hitch, rather bubbling up in the process.

However, in most lights they are, if not invisible, at least easy to ignore.

But this week this happened: another full-impact pigeon mark. And look closely and you can see that the imprint goes slap bang over the sparrowhawk decal.

So, on that evidence, I think it is going to have to be black stickers on the outside of all the windows. It has got to be worth a bit of obstruction of my view to reduce this carnage.

If you have any tips of things you have tried and seem to have worked, do let me know.

Anonymous