Turbines and Birds

We know that wind turbines kill birds. I'm not sure why, presumably they look like a good place to roost.

I am minded to think that this is not a major problem and Darwin will sort it out over a few generations, but does anyone want to tell me I am wrong?

As far as I'm aware, during discussions on one of the pond warden courses that I have been on the average wind turbine actually kills less birds than the average domestic mog, which I believe does something like 30 - 40 per year...

P.S. that wasn't me having a go at catssss again, just relaying facts that I have been made aware of...

Hairyloon wrote:We know that wind turbines kill birds. I'm not sure why, presumably they look like a good place to roost.

I am minded to think that this is not a major problem and Darwin will sort it out over a few generations, but does anyone want to tell me I am wrong?

NO! that attitude makes me mad !!! It's NOT ok to chip birds. If you think anything is less worthwhile than you then you will harm it through uncaring.

The low-level noise the turbines create also causes a lot of pain and proiblems to animals and birds, and bats. They deny habitat to predators when in those ugly great windfarms. The farms produce a pitiful amount of energy and the length of the wires to bring the power to people from the farms loses masses of energy along the way. The turbines crack up by 20 yrs. etc, etc, etc ...

Yup, you got it! I hate the bloody things !!!

What do you call an "average" turbine?
Most turbines that I've seen are the great big ones.
(BTW Anyone happen to know how big they actually are?)

Personally, I rather like windmills of all sorts. Probably spent too much time watching Camberwick Green at an impressionable age.

The problem is, all methods of generating electricity have their price. I assume all of us here would prefer to have electricity available (or this forum would not exist !), so you have to decide what is the least worst.

Wind turbines have a number of criticisms made of them, but the important one is that they simply won't make enough electricity by a very long margin.

Peak output figures :

North Hoyle: 60 MW (30 offshore turbines)
Rhyll Flats: 90 MW (25 offshore turbines)
Gwynt y Môr 576 MW (160 offshore turbines, not yet constructed)

Sizewell B 1,195 MW (most recent UK nuclear)
Drax 3,960 MW (largest UK coal plant)

You should now begin to see the scale of the problem. You would need over 1000 of those turbines to replace Drax. On a windy day. That's not to say they can't be a useful contribution but, though I don't like having to accept it, it is probably fair to say that the only option if we are to avoid fossil fuels or considerable hardship (and I don't just mean no Homemade Life !), involves nuclear.

We have a very long coastline. Plenty of room to stick well over 1000 turbines, and it is very doubtful that the whole coast would be becalmed.

The only problem is from all the NIMBYs. Considering what happened at Rhyl I have no sympathy for any of them.

sparhawk wrote:the average wind turbine actually kills less birds than the average domestic mog, which I believe does something like 30 - 40 per year...

Got any stats for that?
I've heard a take which suggests significantly higher.

Hairyloon wrote:We know that wind turbines kill birds. I'm not sure why, presumably they look like a good place to roost.
?

Let's start there with an understanding how/why wind turbines kill birds. That's a function of the size and "solididty" of the turbine when operating (and the size of the bird and the speed at which the bird flies through the swept plane). Perching isn't an issue as that would only happen when a turbine wasn't turning and if bird were on the baldes and they began turning, at start up the "solidity" would be low (and the birds easily escape).

Let's say we have a two bladed turbine 30 m in diameter and the blades are designed to operate at a tip speed to wind speed ratio of 10:1 (until "feathering" a too high wind speeds). So if the wind speed is 10 m/sec the tip speed is 100 m/sec and the prop is turning at about 1 rev/second. Two blades so a blade passes by a given point every half second. The blades have a certain axial thickness and the bird has a certain size and is flying at a certain speed. So you can calculate the time required to fly the distance of of the axial size of the blade plus twice its own length. That time of course depends on the speed at which the bird is flying. Let's try some numbers.

Say it's a large bird like a crow (0.3+ m) and the blade has an axial depth of 0.3+ m so that gives about 1 meter. Say the bird is flying at 10 m /sec. So it takes 0.1 sec to clear the blade giving an 80% chance that it will pass though safely. Or the other way around, that it has a 20% chance of getting hit. This was of course for out near the tip but since most of the swept area is out there won't be a lot less when you sum up for the radii where the blade is truing more slowly.

A smaller bird would have a better chance of getting through as would one flying faster. Like early WWI fighter planes able to shoot through their own propeller with just a deflector to protect the blade (most bullets, small and very fast, got through undeflected --- but they soon invented an "interupter" firing mechanism that timed the bullets to miss).

If the turbine were smaller it would be turning faster with the imaginary distance between passage of the blades by a given point shorter and almost no chance a bird could get through. Not unlike with water trubines. Fish might have a reasonably high survival rate passing through a large Kaplan turbine but not a small one.

So for wind turbines, as far as bird survival is concerned, one 60 m diameter is better than four 30 m ones.

Hairyloon wrote:

sparhawk wrote:the average wind turbine actually kills less birds than the average domestic mog, which I believe does something like 30 - 40 per year...

Got any stats for that?
I've heard a take which suggests significantly higher.

for cats? I find that difficult to believe. Given the number of cats that are in flats, sedentary/old etc, that average would have to mean most domestic cats taking a bird a week or more. Our cats, which are all quite active hunters probably take less than one bird a month between them. Rats and mice galore but nowhere near that number of birds.

Sorry, typo: that should say tale, not take, and I was referring to turbines.

Yeah, I assumed you were. it was the original statistic of each cat taking an average of 30-40 birds a year. Given that there are 10 million cats on the UK that is 300-400 million birds a year... which is a quite staggering number.
Also given that roughly half of those cats are more than 8 years old, which is pretty senior for a cat, and they tend to hunt less if at all in old age, and those younger cats must be damned busy.

This page:
http://www.songbird-survival.org.uk/predators/domestic-and-feral-cats/

seems to suggest a total possible number of 37 kills per cat per human year, which includes mice, rats, voles etc and something more in the region of 5 or 6 birds apiece, which seems more plausible (pawsable?) to me.

Back to wind turbines, I would think significantly more birds die from flying into windows than wind turbines, and glass has been around a long time but Darwin hasn't caught up yet.

Although I believe hedgehogs have learned to flee from headlights instead of freezing in their path, so who knows.

It would be interesting to compare bird deaths from wind turbine collisions with say, bird deaths from particulate emissions from power stations. Or woodburning stoves for that matter.

When they said "average" cat, they may not have meant "mean".

I'm still puzzled why, given all that sky to choose from, birds pick the bit with a big fan spinning in it. :?

Any cat killing that many birds is a pretty mean kitty.

Unfortunately I don't have the stats, I think they were given to us to encourage further research, plus of course, at the time there were less turbines so the proportions would naturally have been more for the mog...

Thanks CW for the linky which amongst other things says:

If wind farms are located away from major migration routes and important feeding, breeding and roosting areas of those bird species known or suspected to be at risk, there is a strong possibility that they will have minimal impact on wildlife.

Therefore with the numbers of mogs (carefully watched over by their owners) & the numbers of mogs that aren't, & the willy nilly spread of the aforesaid creatures add into the equation the number of feral mogs that don't have homes to go to or caring owners who feed them the figures soon mount up...

Thanks Billy for your linky too but I think that survey would only have been responded to by responsible owners, therefore it ain't a fair reflection on the average:
"I've got a cat & fill its bowl with food once a day before I go to work" person who only sees the aforementioned critter for a couple of hours between coming home from work & going to bed each day...

Although I am not so sure that the current wind farms we have are the best way to harness the energy, or the safest...

HL, I was only trying to give the figures as was discussed at the meeting I was at & tried not to take this into another "Catsss versus whatever discussion" as there are of course the kitties that are looked after 24 hours a day by responsible owners so that they would never revert to their natural instincts & therefore would not go chasing any feathery creature, & to be fair I have never seen a wind turbine chasing a feathery creature either...

Nor yet a cat generating electricity.

Possibly an honest mistake? Accidentally combining say "the average cat maybe 30 kills per year" and "cats will kill birds" into "the average cat kills maybe 30 birds per year".

In my experience, the average cat kills at least 10 rodents, frogs, snakes, etc. for every bird it get. Which means that the average cat would have to be killing 300+ critters per year (one a night). Since most don't get out there to do any hunting the active hunters would have to be awfully active!

It does disturb me a bit, this feeeling that a responsible cat "owner" should try to overcome the cat's instinct/desire to hunt. Why? What is wrong with a predator being a predator? Even if you think it wrong for you to kill and eat other animals why do you consider that wrong for a cat? (what does that say about your attitudes toward the "rightness" of Nature)

Just my opinion, but if having a predator as an animal companion bothers you maybe you should consider a different sort of animal companion. The only reason different from a dog is that the dogs desire is that you go out and hunt as a pack (and going out together on a walk together satisfies half of that even though "the team" doesn't follow through and chase something down).

Curiously, following on from this thread, I had a very vivid dream last night that some kind of big cat - a puma or similar - was killing all of my chickens, which in that particular space, number 30.

I walloped it with a snow shovel (no idea why I had one to hand) and it leapt on me and started chewing my face off. I was desperately trying to reach a metal tent peg that was holding down the electric fence to stab it in the eye. And then I woke up.

Mike wrote:
It does disturb me a bit, this feeeling that a responsible cat "owner" should try to overcome the cat's instinct/desire to hunt. Why? What is wrong with a predator being a predator? Even if you think it wrong for you to kill and eat other animals why do you consider that wrong for a cat? (what does that say about your attitudes toward the "rightness" of Nature)

It is not that cats being predators is wrong or unnatural. It is the circumstances and the density at which they are kept that is not natural (there are 9 million of them in the UK).

Elen Sentier wrote:

Hairyloon wrote:We know that wind turbines kill birds. I'm not sure why, presumably they look like a good place to roost.

I am minded to think that this is not a major problem and Darwin will sort it out over a few generations, but does anyone want to tell me I am wrong?

NO! that attitude makes me mad !!! It's NOT ok to chip birds. If you think anything is less worthwhile than you then you will harm it through uncaring.

The low-level noise the turbines create also causes a lot of pain and proiblems to animals and birds, and bats. They deny habitat to predators when in those ugly great windfarms. The farms produce a pitiful amount of energy and the length of the wires to bring the power to people from the farms loses masses of energy along the way. The turbines crack up by 20 yrs. etc, etc, etc ...

Yup, you got it! I hate the bloody things !!!

But the same agruments about the energy loss in the cables applies to all electrical generators , and I know I would rather have a (non nuclear) renewable source of electricy sending the electrons down the lossy cables, than a fossil fueled one.

Wind farms in the right place have a huge potential to help us with our ( hopefully also diminishing, due to less consumption) energy needs...

Its when they are sited in damn fool places like estuaries which are home to vast populations of breeding birds, or on a migration route, that they become wrong, in exactly the same way as ANY development which ignores the needs of any flora or fauna, is wrong.

Planning regs ( even the rubbish watered down versions we now have, thanks to Nu Labour and their cronies) should stop that sort of thing, but often it takes concerned citizens to make a fuss, and even then it doesn't always work.

But that is the fault of the system, not of wind turbines , in themselves.

I agree it is NOT ok to chip birds, and NO Darwin will not "sort it out" . its up to us not to site things in stupid places.

Power loss in a cable is inversely proportional to the voltage squared.
At 20.000 volts, the power loss is trivial.

Was just making the point that it is , however trivial , irrespective of the generator.

I would, however argue that ANY loss is a BAD THING

Which is why microgeneration is such a GOOD THING

Which is why I wondered if all new builds should be made to have some sort of microgeneration either wind turbine or solar...

Also instead of throwing billions at more nuclear power in the future why not bring down the costs or even provide free solar/tubines to every home thereby turning the country into one huge power generator, also creating whole new industries both in the manufacture of & installation of said things, & that much use would also create reasearch opportunities to make them more efficient...

Unfortunately not all newbuilds are suitable for microgeneration. If you have a North facing mid terrace midfloor flat for example.

Also for renewables to actually contribute significantly to the energy use of a property you need a fair chunk which would significantly increase build costs. At the lower end of the market - so called 'affordable housing' this would cause major problems.

That said, in October the Building regulations will change to require a 25% improvement in energy efficiency over existing standards. In two years time it will increase again to 33% of present and again in 2016, and again, I forget when after that. The 25% is just about achievable without renewables if the building fabric is made super insulated etc, but 33% is not achievable without onsite renewables, so this is all in the works.

The original plan was for Code for Sustainable Homes to become mandatory in full but it is only the energy aspects which have been adopted nationwide (althoug it will be mandatory in forward-thinking Wales). This is a little bit of a good thing - really we need the water aspects and so on as well.

I agree about micro-generation, much better than the farms.