City Slicker Birds Shun Their Country Cousins 95
According to scientists, city Great Tits prefer other city Great Tits over country Great Tits. (Lets act like adults). The researchers found that the city dwellers responded more strongly to songs of fellow city dwellers and the same held true for the bumpkins. The average minimum pitch of male Great Tit songs in noisy urban areas was higher than in quieter, rural areas just a few miles away. Dr Rupert Marshall, of Aberystwyth University, Wales, and his team recorded bird song in 20 different cities in Britain. He says, "People speak louder and higher in noisy places like pubs and bars but still recognise their friends' voices once they go outside. Great tits seem to learn the high notes from their neighbours but don't respond as strongly to lower rural tones even when it's quiet."
Adaptation - Evolution (Score:3, Informative)
i myself prefer boobies (Score:3, Informative)
http://www.galapagosonline.com/Galapagos_Natural_History/Birds_and_Animals/Birds/Boobies.html [galapagosonline.com]
Re:City tits are perkier than country tits (Score:5, Informative)
Re:The study isn't sufficient. (Score:5, Informative)
They would need to examine the reaction of different populations from the countryside to see if the reaction is simply one of disputes between avian clans. As it stands, their data could mean too many different things. The adage, often repeated here, is that correlation is not causation.
As your knowledge of bird behavior stands, yes, it could mean just about anything. When you know nothing else but that correlation exists, then this in fact does not indicate causation. However when someone possess knowledge of other factors that suggest causation, then correlation can in fact support the causation conclusion.
In this case, a "dispute between avian clans" can easily be ruled out. You see, when a breeding male tit hears the call of another male tit nearby, that male will sing its own song to proclaim its territory, or investigate the source of the call in order to drive the intruder out. If the male country tit recognized the call of the male city tit, but didn't like city tits, then it would have responded more aggressively in trying to drive out the intruder. The lack of a response means that the country tit did not consider the city tit to be a threat, making the most likely explanation that the country tit didn't recognize the city tit's song as being that of a Great Tit at all.
There is as they say more research to be done. The next step is to see how females from each group respond to the calls of the other group. This is going to be trickier. While a male will react to any male that enters its territory and thus threatens its chances to mate, a female may or may not respond to the call of a male for any number of reasons. However if city tit females routinely reject the calls of country tit males and vice versa, then the question of whether the female recognizes the male call but just doesn't like it vs doesn't see them as the same species becomes largely moot. If the females aren't attracted to the other males, they won't breed, and they will slowly begin to separate as species.
On the other hand, if females don't appear significantly less attracted to the other males, then well I'm not really sure what would happen since I'm not terribly well versed in Great Tit behavior. It might mean more females breeding with multiple males on the edge of cities since the city/country males wouldn't compete with each other. It might mean that a bird born from mixed parentage would learn both songs, possibly eliminating the difference.
Re:Is that really a surprise? (Score:4, Informative)
Is it necessarily evolution? Or is it simply training? I bet if I took a bird egg from the country and swapped it with one from the city, that the birds would identify with their adoptive culture.
Either way the result will be evolution. Even if the different call is learned behavior (which they theorize is the case), if the females from one group won't respond to the calls of the other (which they haven't tested yet) then they won't interbreed and barring substantial egg-swapping efforts by humans they are effectively different species on their own evolutionary paths.
Re:Is that really a surprise? (Score:3, Informative)
And it's a fairly valid point. There is a big difference between differentiation and evolution, and the blurred line between them by many "science buffs" is why they're scoffed at by ID proponents.
Re:Is that really a surprise? (Score:3, Informative)
This just theoretically reduces the alleles available to given sample... it isn't genetic evolution, which I think is the point being made.
Change in allele distribution is evolution. And once there are two separate breeding populations, any further mutations or allele frequency changes will not be transferred to the other group, and thus clearly it is only a matter of time until they are different enough that anyone can see that genetic evolution has taken place.
And it's a fairly valid point. There is a big difference between differentiation and evolution, and the blurred line between them by many "science buffs" is why they're scoffed at by ID proponents.
The line is blurry, and the inability of ID proponents to comprehend this, and most other things they ignorantly scoff at, is why they are scoffed at by biologists.