Richard Bell's nature sketchbook since 1998
These sketches from the hospital and the one of the wood were drawn with one of my regular fountain pens, the TWSBI Eco T.
But I’ve gone back to a fibre tip for these wood pigeons and sparrows in the back garden.
These were drawn with a Mitsubishi uni pin 0.3 fine line, which has water and fade proof pigment ink.
It’s that time of year when blue tits and sparrows fight it out for who gets to nest in our various nest boxes. Last year the blue tits raised a brood in the sparrow terrace at the back of our house but after a lively dispute between a pair of sparrows and a pair of blue tits over the blue tit box in the rowan tree in the front garden, the box ended up with no occupants during the breeding season.
History is repeating itself with the blue tits franticly trying to repel the sparrows at 8.30 this morning but the sparrows managed to force their way to the box and, as it turned out, despite the narrow dimensions of the brass ring around the entrance hole, they were able to squeeze in.
At the moment it’s sparrows who are taking most interest in the three-nest hole sparrow terrace but it’s early days and the blue tits could easily be the ones who eventually take possession.
First visitor to our new sparrow nest box: a blue tit. It checks out hole number three first; no, that’s not quite right; then hole number two and it’s just about to investigate hole number one when a second blue tit appears, there’s a skirmish and off they fly.
It’s likely that, as this RSPB box was made specifically for sparrows, the blue tits will find the entrance hole a little too wide for their liking but the old box, single-holed variety, attracted blue tits one year, sparrows the next (and finally bumblebees), so we’ll have to wait until springtime to find out who finally takes possession.
4.25 p.m., 40ºF, 5ºC: I find peonies more interesting to draw when the buds are opening up than when they open up into frothy flower-heads, which in our garden often get battered down by summer rain.
There was a dispute over the patio nest box this afternoon: two blue tits looked on anxiously from the clothes line as a female sparrow perched on the front of the box taking a good look in the nest-hole. 
Sparrows and blue tits took an interest in the box last year but it was finally occupied by red-tailed bumblebees. These birds had better stake their claim soon.
It’s good to see starlings making a comeback. Once ubiquitous, they haven’t been much in evidence in recent years but most mornings a few of them gather on the rooftops across the road. Sparrows should have a good year too to judge by how many times I’ve seen a pair of them mating. They 
always perch on the gutter on the corner of the house diagonally opposite us. Perhaps this is the best spot if you want to avoid a stealth attack from a sparrowhawk.
This photograph looks rather like a scree-slope on a Lakeland fell but in fact each of these slate-like fragments is less than a millimetre across, smaller than the commas on this page. It’s a piece of roofing felt taken at 60x magnification through my microscope. The felt is bitumen-coated with a ‘green mineral’ finish, but it looks browner in my photograph. The flaky shapes and the colour make me guess that this is a green variety of Muscovite mica called fuchsite. The flakes (laminæ) of Muscovite are thin and surprisingly flexible, so they’re ideal as a coating on rolls of roofing felt.
There’s another mineral present; the rounded, glassy mineral near the bottom left-hand corner is a worn grain of sand, silica.
Fuchsite is rich in chromium but like other micas, as a form of silicate, it has a chemical composition based on aluminium, silica and oxygen (AlSi3O10). Micas are part of the group of minerals known as Phyllosilicates or sheet silicates, which take their name from phyllon, the Greek for leaf.
It was sparrows pecking on our newly felted shed roof that prompted me to take a closer look at its composition. Why should sparrows feel the need to peck at flakes of mica?
Muscovite is 2-4 on the Mohs scale of hardness, depending whether you’re testing the softer ‘sides’ or the harder face of the flakes. This means that it’s somewhere between a finger-nail and a pocket-knife in hardness, so the sparrows might swallow it as a form of ‘gritting’. The flakes might be used in the bird’s gizzard to help grind down the seeds and grain that form its staple diet. Fuchsite is made of clayey minerals so it might also have medicinal properties that help with digestion, just as we’d take kaolin, a fine white clay that is another form of sheet sillicate.
Sparrows will also peck at mortar on walls (right), which gives them access to more minerals; silica in the sand and the calcium carbonate in the cement.
When Paul and I put the new roofing felt I predicted that the sparrows would love it: “It’s like putting a new sheet of Tydsan in a budgie’s cage!”
Tydsan is the trade name of sheets of sandpaper, cut to size.
“Our budgies had to make do with newspaper in their cages!” Paul tells me.