Re: Penguins of the North...?

["David Marjanovic" <david.marjanovic@gmx.at>]

> There was a suggestion from HP Ron Orenstein that auks are more diverse
> than penguins.  Technically this is true.

I don't know how much it actually matters or whether only the flightless
ones -- *Pinguinus*, *Mancalla* and AFAIK none others, plus the plotopterid
pelicans -- could be counted as possible competition in the first place.

> However, the inference that is
> drawn from this--viz., that the penguin niche is just as fruitful
> in the north as the south,

but not in between.

> and it's only because of competition and/or
> lack of transport in cold currents that they don't invade the north--does
> not follow.

It's not transportation why cold currents are -- apparently -- essential.
The nutrients they bring are what matters. Close to the Pacific coast of SA
the Humboldt Stream is teeming with life, whereas farther to the west
there's nothing but blue desert. Equatorial waters don't support such
ecosystems.

> Finally, while penguins may
> indeed be prevented from migrating north by lack of cold currents, flying
> auks would seem to have fewer restrictions on their mobility.  Why, then,
> did they not invade penguin territory: perhaps because the penguins are
> better competitors where they are able to nest!

IMHO it's just the same thing as with penguins -- the cold currents from the
north don't reach the equator either. (That's particularly extreme in the
Atlantic where the Gulf Stream keeps all cold waters north of almost
Newfoundland.)
Were is the southernmost auk? In California? Where were the southernmost
plotopterids?

> Thank you, thank you very much.

For what?