Well, it's midsummer again, and time for country walks, and rambles in the fields, and being shouted at by angry farmers, and finding footpaths blocked by barbed wire, and all that sort of thing that the British do so well.

Not unnaturally I am being inundated with queries about life in the countryside. And that means it is time again to bring on our no-nonsense nature expert, Herb Robert, to answer all your questions on wildlife - all yours, Herbie!

Why do dead fish float on the surface of rivers and canals?

Herb Robert writes: So that seagulls can eat them. Next!

Why are wagtails called wagtails?

Herb Robert writes: Because they wag their tails. Next!

No, no, hold on a minute, that's not strictly true, is it? I mean, dogs wag their tails from side to side, which is what we call wagging. But wagtails oscillate their tails up and down, which is more like nodding. They should be called nodtails, if anything.

Herb Robert writes: All right, wise guy. Let's take this one slowly. What do humans do when they are in disagreement?

They say, "I disagree".

Herb Robert writes: Yes, yes, but if they don't say anything? If they just use body language?

They shake their heads.

Herb Robert writes: Ah ha! So when humans do it to their heads, it's called shaking, but when dogs do it to their tails it's called wagging, is that right?

Yes, I suppose so.

Herb Robert writes: You're just a troublemaker. Next!

I have often heard it said that animals who are in danger like to be downwind of their attackers. That is, a rabbit can smell a fox upwind, and a fox can smell hounds upwind and so on.

Herb Robert writes: Ye-e-es...

So it makes sense for animals to get to windward of their attackers, or potential attackers.

Herb Robert writes: Ye-e-e-s...

Well, as the prevailing wind in Britain is a west wind, which blows most of the time, an animal to the east of its hunter can always smell it, so you would expect animals in Britain to move to the east - on the whole - to be in a safer position.

Herb Robert writes: Ye-e-es...

Therefore, over a long period of time, you would expect a general drift to the east of the island among hunted animals, followed of course by their hunters. So it would only be natural if you found that the eastern side of Britain was much more heavily populated by animals who were moving to the east to avoid being smelt, and that the west was almost completely denuded of animals. Is this in fact so?

Herb Robert writes: No. You are talking rubbish. Attractive rubbish, but still rubbish.

Do you approve of pox-hunting?

Herb Robert writes: I most certainly do. The quest to eradicate smallpox was one of the most exciting missions of modern man. Ah, yes, many's the time I've been out in the early dawn with a bunch of pink-coated scientists, chasing the pox over dale and hill!

And now I'm glad to say the little bugger has been eradicated. No more smallpox! Geese and chickens can now sleep safe at night, knowing they will never have dreadfully scarred faces. Of course, that means no more pox-hunting, and sometimes I miss the old days, but I think this is a small price to pay...

Sorry - did I say "pox-hunting"? Of course I meant "fox-hunting"!

Herb Robert writes: Now, there are some people who were vehemently against pox-hunting, and said that a virus was just as much God's creation as a human being, and of course we had lots of trouble with saboteurs in the laboratory - I'm sorry? Did you say something?

Yes. The other day, at the far edge of a field, I noticed three birds hovering absolutely motionless side by side. They were so still you couldn't even see the wings moving. Then a fourth bird joined them in this strange hovering performance but directly overhead the other three. What on earth was going on?

Herb Robert writes: They were sitting on telephone wires, you idiot.

Thanks again, Herbie. Keep those nature inquiries rolling in!