We have three bird baths in our garden. They are really just big plastic pots that came with Christmas trees past, sitting on a wall about meter apart; there are three of them because our resident blackbird is an antisocial sod chasing other birds off, but he can’t police all three.

Thing is, our small, unkempt, urban garden sees lots of different birds in the course of the year: magpies, pigeons, blackbirds, starlings, sparrows, blue and great tits, dunnocks, robins, wrens are present all year around; chaffinches, hawfinches, bullfinches and goldfinches come frequently for dandelion seeds in the spring and umbellifers in the autumn and winter, a mistle thrush and fieldfares arrive in the winter for apples and holly berries; last winter there was briefly a redwing and a snow bunting, we have a garden warbler nesting just now.

The grass, most of which I let to go to seed, is popular with a surprisingly wide variety of small birds, as are the greenfly and other aphids on the currents and the honeysuckle, which, together with the perennial sawfly caterpillars, are a staple diet of our blue tits and their brood (I used to fret over the sawfly, but don’t any more, the bushes survive it just fine, and it doesn’t seem to impact the crop, if anything, it exposes the berries to more sun).

In the spring we have a few birds nesting in the garden, plus it is the neighbourhood’s favourite stop for building materials. I keep a twig heap along the back fence, where I put what I prune from my fruit bushes, plus lovage stalks and such; it’s meant for the overwintering of bumblebees, but the bigger birds such as pigeons, magpies and starlings make good use of it too come spring. By one of my two vegetable beds there is a small pile of grass cuttings and moss raked out of the 3m x 3m ‘lawn’ I maintain for a brolly to sit under, and this has proved popular with blackbirds, and sparrows, while the warblers harvest moss directly from our old apple tree.

And so these bird baths are very popular all year around, but particularly so in this hot weather spell, and I keep them topped up to the brim, so that when the smaller birds use them their sight doesn’t get obscured by the rim, in case there is a cat around. And, of course, I empty them to refill with fresh water when they get too dirty.

When I was doing this at the start of the week I noticed that one of the baths was much filthier than the other two, but didn’t think much of it. But the next day, when I was topping up, that bath was again already quite a bit dirtier than the other two, and by yesterday morning it was outright minging, while the other two were still clear.

Well, yesterday I found the culprit: almost every time I looked out of the kitchen window, I saw a female blackbird arrive at the small heap of moss and grass cuttings, pick up a good bunch with her beak, hop up on the nearest bath and give it all good dunking, before flying off into a neighbour’s tree! Indeed, the BWP tells me that the structure of a blackbird’s nest is usually plastered with mud before being lined with fine grass, so I guess that is how it’s done.

(TBH, I am somewhat surprised to see a nest being built a this time, for there are already young blackbirds around; I worry greatly about them, for unlike the sparrows, that seem to become quite streetwise fast, the young blackbirds are clumsy gullible fellows that don’t have enough wits about them to stay safe from the cats and magpies; the latter I accept as part of life, but the cats I do my best to keep out of the garden.)