DURING this morning's daily walk, I heard the sound of wood being tapped and my first reaction was that a woodpecker was busy.

Almost immediately, however, I realised it was not the rhythmic battering or drilling type of sound one associates with those amazing birds. It was more like someone lightly tapping a branch with another piece of wood.

It took a few seconds to determine the whereabouts of the noise, but I soon discovered it came from a huge ash tree and then I saw the culprit.

It was a crow (not a rook) and it was tapping a thick branch with the side of its beak. I watched for a few moments until the bird became aware of my presence not far below, and then it flew off.

But what was it doing? I wondered if it was cleaning its beak, perhaps trying to dislodge something which had become stuck to it, or was it tapping the bark to alarm hiding insects into breaking cover so that it could have a quick snack?

Blue tits perform a similar ritual when they first make use of a wooden nest box. They rapidly tap the insides of the box so that it sounds like a drill at work, and this dislodges tiny insects which are lurking in the crevices.

This is not done to provide blue tits with food, however. It is part of their domestic cleaning process. But a crow tapping the bough of an ash tree? Why would he (or she) do that?

Further bird stories intrigued me during the past few days. One concerns a family of wrens. We became aware of much loud chirping in the shrubs and the beech hedge which form part of our garden and soon realised it was coming from lots of tiny wrens.

Those cultivated growths provided just part of their cover because the birds were spread around the garden in all manner of places and it was difficult to count them because they moved so quickly, darting from one hiding place to another with amazing speed.

On one occasion, we were enjoying lunch on the terrace and the little birds appeared to ignore us as they went about their urgent business only yards away, but it was soon evident it was a family of baby wrens.

One of the parents was in charge, for it was quickly noticed that he or she would issue some kind of instruction to the others, upon which they would respond with their own chirps and then dart to some new hiding place.

Wrens can produce up to eight youngsters in one nest - I reckon this family consisted of six or seven little ones - and both parents share the burden of feeding them. Consequently, the presence of this busy group made me wonder whether our garden had been the site of their nest.

Certainly, over the summer, we have noticed wrens in the garden, sometimes deep in the ivy which clings to one of our walls, and at other times darting about the shrubbery in the never-ending search for food. But I have never discovered their nest.

As I compile these notes after enjoying morning coffee in the garden, I have to say there was no sign of our wrens.

With binoculars, I searched the beech hedge and surrounding shrubs, but it seems the wrens have departed.

Whether they have all left home individually to make their own way in the harsh world, or whether they have moved as a family group to another temporary base, I cannot be sure.

I hope the coming winter will not be too severe for them. Any hard winter is a trial to wrens; being so tiny and vulnerable, they soon fall victim to severe frosts and cold weather and, quite suddenly, numbers of living wrens can plummet alarmingly. I hope our little family finds somewhere safe in the weeks ahead.

Another bird story occurred during my morning walk. As I crested the brow of a hill, I was faced with a tremendous commotion among a group of small birds and, at my approach, a kestrel burst from cover beneath a hawthorn hedge.

He was closely pursued by a surprisingly large crowd of assorted small birds.

Among them I noticed hedge sparrows, house sparrows, skylarks, swallows and a chaffinch, all chasing the intruder from their patch.

I watched as he flew away over some farm buildings with his retinue of small birds chasing behind. He seemed to ignore them completely, but I wonder if my presence disturbed his breakfast, or whether the lynch mob had persuaded him to try elsewhere.

In watching those small birds in action, I thought they must be very brave or very stupid. Just suppose the kestrel had turned around and faced them - would they have fled for their lives or resorted to some other tactics?

We shall never know because, after a few hundred yards, they abandoned their chase and returned to their normal lives. I am sure each one thought he or she had done a wonderful job in ridding the area of such a dangerous predator.

Among my correspondence this week is a letter from an 89-year-old woman who lives near Thirsk.

She is responding to previous notes about the death of a calf which originally featured in this column on July 12, followed on August 23 with a response from the RSPCA.

The original story, which occurred at Whitchurch on Thames, was that a trespassing rambler had found a calf in a distressed state and had called the RSPCA and a veterinary surgeon.

Without the knowledge or consent of the calf's owner, they had then attended the animal, which subsequently died.

The RSPCA responded to the effect that the calf was so severely ill that it had to be treated immediately, even without the knowledge or consent of its owner.

The RSPCA says that, upon the advice of a veterinary surgeon who was present at the time, it acted in the best interests of the calf, which died soon afterwards.

My correspondent, who is the mother of the calf's owner, tells me that the calf had already been treated by the owner's vet, with both the owner and the vet remaining with the sick calf until 8pm.

When they realised nothing could be done to save the animal, the correct procedure was followed, ie it was left with its mother, who would have accepted its death as a natural event.

Instead, the trespassing person saw the sick animal and called the RSPCA, who then, without consulting the owner, removed the calf from its mother.

The herd in question is the White Park rare breed, which always live outdoors and never enter buildings, so it was natural for the sick animal to be outside.

At 7am next morning, my correspondent's son went to examine his calf, fully expecting to find it dead alongside its mother, but the calf had disappeared, leaving a severely distressed mother cow.

My correspondent feels that the people who treated the calf should have known more about animal behaviour in general, and these animals in particular.

She then reports another similar incident. A stockman found a beast with an infected foot, having cut it on some wire.

Very experienced, and with the necessary means, he treated the wound, but someone else reported the animal to the RSPCA, who are now prosecuting the stockman for cruelty.

He cannot prove that he treated the animal's wound and his livelihood is now in jeopardy.

Having supported the RSPCA throughout her life, my correspondent now says she will never again do so.

Each of these cases highlights the problem of well-meaning, but ignorant people wandering about the countryside and interfering in things about which they know nothing.

It must make us all wonder with deep apprehension about the probable effect of the right to roam policy.

And finally, here's a short tailpiece. A village lad was strolling along the street when a neighbour met him. "Hello, Johnny," she smiled. "Where are you going?"

"Ah's nut gahin onnywhere," said Johnny. "Ah's just coming back from where Ah've been.