Things you always wanted to know the answer to [Vol. 4]

[Nimby]

neelyp said:

Why do birds never breed with other types of birds and create mongrels?
Obviously not thinking about seagulls and sparrows getting jiggy, but finches and tits are much the same size so why don't we have fits or tinches?

They do, and it can be a problem eg. Ruddy ducks and white-headed ducks.

Also there are several bird ring species. Creationists hate ring species!

[Fastchas]

neelyp said:

Why do birds never breed with other types of birds and create mongrels?
Obviously not thinking about seagulls and sparrows getting jiggy, but finches and tits are much the same size so why don't we have fits or tinches?

Birds are a variety of a species, like fishes. They can't breed with other members in the same species
To compare humans, we are a species but a mammal. We can't breed with other mammals ie; dolphins/lions/rats etc.

[V8mate]

Fastchas said:

neelyp said:

Why do birds never breed with other types of birds and create mongrels?
Obviously not thinking about seagulls and sparrows getting jiggy, but finches and tits are much the same size so why don't we have fits or tinches?

Birds are a variety of a species, like fishes. They can't breed with other members in the same species
To compare humans, we are a species but a mammal. We can't breed with other mammals ie; dolphins/lions/rats etc.

Yeah, but I saw a video where... oh, no, hang on...

[Shakermaker]

Fastchas said:

We can't breed with other mammals ie; dolphins

Don't tell Troy McClure

[john2443]

Mothersruin said:

Also, they usually have their own advertising/contact details in big signage attached - free advertising.

They must have their contact details on - council requirement - so that if it falls down / gets driven into by a lorry etc the council or Fire Brigade can contact them - I had a friend who worked for the council and it was part of his job to contact them.

[HTTPies]

Why are human chest hairs tapered, and how does this happen?

[SpeckledJim]

HTTPies said:

Why are human chest hairs tapered, and how does this happen?

So your arse doesn't shut with a bang?

Oh, no, that's turds.

[Dr Jekyll]

SpeckledJim said:

It's a sort of circular answer, but one of the things that makes them different species is the fact that they can't breed with each other.

Don't forget that the 'pedigree' dog breeds are man-made monsters and only a few hundred years old. Selectively bred for our selfish (often just entertainment) purposes.

I always wondered how prehistoric Poodles managed to survive in the wild.

SpeckledJim said:

In the wild, left to breed as they would naturally, there would be nowhere near the variation in breeds of dog, as they'd all be mongrels of a type.

The question is really not so much why are sparrows and chaffinches so similar, it's more like why are dogs so diverse, and the answer is 'because humans really, really mucked about with them, essentially for their own amusement'.

Back to birds though. There is the example of the European Herring gull which is a different breed from the American Herring gull but can interbreed. Carry on round the world and you find various Siberian gulls which can interbreed with the American Herring gull. The Siberian gulls can also interbreed with the Black backed gull by which time you're back in Europe. The Black backed gulls live alongside the European Herring gull but are too different to interbreed, so regarded as a separate species.

There is a huge grey area between 'can't interbreed at all', and 'can interbreed as a matter of routine'. Even Mules are sometimes fertile.

[glenrobbo]

neelyp said:

Why do birds never breed with other types of birds and create mongrels?
Obviously not thinking about seagulls and sparrows getting jiggy, but finches and tits are much the same size so why don't we have fits or tinches?

A little bird told me that there was a cormorant off his tits that once shagged a shag.

[paua]

glenrobbo said:

neelyp said:

Why do birds never breed with other types of birds and create mongrels?
Obviously not thinking about seagulls and sparrows getting jiggy, but finches and tits are much the same size so why don't we have fits or tinches?

A little bird told me that there was a cormorant off his tits that once shagged a shag.

That may well be, however, I've not seen a royal albatross riding a sparrow.

[Clockwork Cupcake]

paua said:

That may well be, however, I've not seen a royal albatross riding a sparrow.

Is that an African or European sparrow?

[underwhelmist]

SpeckledJim said:

neelyp said:

SpeckledJim said:

I think you're confusing breeds with species.

Dogs of all breeds can breed with each other, as they're all the same species.

Sparrows and Chaffinches are different species, as are dogs and cats.

There are different 'breeds' of human (for want of a better description. 'Race' is the word we use) and we can all breed with each other as we're all the same species.

Yep, getting this.
But, what makes sparrows and chaffinches different species? They seem to have a lot more in common than say, a Yorkshire terrier and a Great Dane.

It's a sort of circular answer, but one of the things that makes them different species is the fact that they can't breed with each other.

Don't forget that the 'pedigree' dog breeds are man-made monsters and only a few hundred years old. Selectively bred for our selfish (often just entertainment) purposes.

In the wild, left to breed as they would naturally, there would be nowhere near the variation in breeds of dog, as they'd all be mongrels of a type.

The question is really not so much why are sparrows and chaffinches so similar, it's more like why are dogs so diverse, and the answer is 'because humans really, really mucked about with them, essentially for their own amusement'.

All dogs, whether Chihauhua or Great Dane, are descended from European Grey Wolves. Have a read of Tamed, by Prof Alice Roberts, it's a fascinating read.

[paua]

glenrobbo said:

neelyp said:

Why do birds never breed with other types of birds and create mongrels?
Obviously not thinking about seagulls and sparrows getting jiggy, but finches and tits are much the same size so why don't we have fits or tinches?

A little bird told me that there was a cormorant off his tits that once shagged a shag.

Groundhog day?

[Johnspex]

Mothersruin said:

Shakermaker said:

Johnspex said:

Second question; how does the scaffolding business work? You see scaffolding left on sites where the job has obviously finished but the scaffolding stays up for ages. Doesn't the scaffolder need it for more jobs?

Yeah but the longer its rented for, the longer they can charge for it.

And leaving it up on a site when it doesn't look like it is needed anymore, also means they don't have to store it in the yard, and can simply take it down a day or two before they need to take it on to the next site, and then leave it up there until it is needed again somewhere else

Also, they usually have their own advertising/contact details in big signage attached - free advertising.

I was led to believe that the user paid a set price and the scaffold stayed as long as was needed. I didn't think it sounded right.

[Clockwork Cupcake]

Johnspex said:

I was led to believe that the user paid a set price and the scaffold stayed as long as was needed. I didn't think it sounded right.

That makes no economic sense.

Although, having said that, back in the day you could hire a skip for as long as you needed it.

[CaptainSlow]

Clockwork Cupcake said:

That makes no economic sense.

It does when you consider off loading into and out of storage and paying for storage costs money. Much better to take down from one site and take straight to the next.

[Clockwork Cupcake]

CaptainSlow said:

It does when you consider off loading into and out of storage and paying for storage costs money. Much better to take down from one site and take straight to the next.

Oh, for sure. But then again you don't want it tied-up for an indefinite period if it's needed elsewhere.

Swings & roundabouts, I guess.

[RATATTAK]

If still in use, scaffolding has to be inspected every 7 days, so there's a cost there too

[alorotom]

Clockwork Cupcake said:

Johnspex said:

I was led to believe that the user paid a set price and the scaffold stayed as long as was needed. I didn't think it sounded right.

That makes no economic sense.

Although, having said that, back in the day you could hire a skip for as long as you needed it.

I know of a couple of skip companies that only charge on removal - no matter how long you have them for, this is Sunderland and Newcastle for reference

[SpeckledJim]

alorotom said:

Clockwork Cupcake said:

Johnspex said:

I was led to believe that the user paid a set price and the scaffold stayed as long as was needed. I didn't think it sounded right.

That makes no economic sense.

Although, having said that, back in the day you could hire a skip for as long as you needed it.

I know of a couple of skip companies that only charge on removal - no matter how long you have them for, this is Sunderland and Newcastle for reference

Perhaps they're in the position of having more skips than customers to hire them, and also than space to store them, so it suits them to have a good portion of them sitting idle on folks' drives.

Supplementary question: Do skips stack? If I've got 3 empty skips and space for 1, can I pile them up?