Monday, June 06, 2005
Stupid dumbarse birds
Soundtrack: "X & Y" by Coldplay
Good arvo this arvo.
I'm posting this first so that the Coldplay review is at the top of the page.
Just adding the next chapter to the bird saga. Those birds are scarily punctual (like fish at feeding time). They only ever attack the window at half-past the hour. That I've remembered, they've attacked at 8.30am, 9.30am, 10.30am and 1.30pm. It's a worry.
And for the benefit of non-Elgarites, here is an analysis of the birds' behaviour by the one and only Stephen "Gorgeous" Maloney:
Steph, with reference to your birds attacking windows (I just got round to skimming some of your blog, but I can't be bothered / don't want to post comment there), it is indeed plausible that a bird could take its reflection for a conspecific and attack. Kusuyama et al. (2000) found that jungle crows do just that, and male pigeons do the same, whilst female pigeons display their own appropriate meeting-a-conspecific behaviour, viz. preening.
Clayton and colleagues, however, found that Western scrub jays (Aphelocoma californica) will cache food in the presence of a mirror in the same way as they would cache food in private, rather than the way in which they cache when observed by a conspecific. There is as yet no clear evidence of a bird passing Gallup's (1970) 'mark test', taken as suggesting some kind of self-recognition. Parrots, although failing the mark test, can use mirrors to locate hidden food, suggesting some appreciation of the properties of the mirror, or maybe just instrumental conditioning.
Finally, horizontal reflective surfaces may be more naturalistic (e.g. pools of water) than the vertical ones (e.g. windows), and thus less likely to elicit the aggressive conspecific-directed behaviour; Kusuyama et al. found that the crows behaved less aggressively to a horizontal than to a vertical mirror.
... furthermore your scepticism of the group-selection / altruism explanation is of course completely justified (did you do A level biology? I didn't so forgive me if I'm wrongly assuming ignorance of evolutionary theories), and your idea that they're trying to get at food behind the glass is perhaps the most plausible of the three...
So that's clear, isn't it?
Good arvo this arvo.
I'm posting this first so that the Coldplay review is at the top of the page.
Just adding the next chapter to the bird saga. Those birds are scarily punctual (like fish at feeding time). They only ever attack the window at half-past the hour. That I've remembered, they've attacked at 8.30am, 9.30am, 10.30am and 1.30pm. It's a worry.
And for the benefit of non-Elgarites, here is an analysis of the birds' behaviour by the one and only Stephen "Gorgeous" Maloney:
Steph, with reference to your birds attacking windows (I just got round to skimming some of your blog, but I can't be bothered / don't want to post comment there), it is indeed plausible that a bird could take its reflection for a conspecific and attack. Kusuyama et al. (2000) found that jungle crows do just that, and male pigeons do the same, whilst female pigeons display their own appropriate meeting-a-conspecific behaviour, viz. preening.
Clayton and colleagues, however, found that Western scrub jays (Aphelocoma californica) will cache food in the presence of a mirror in the same way as they would cache food in private, rather than the way in which they cache when observed by a conspecific. There is as yet no clear evidence of a bird passing Gallup's (1970) 'mark test', taken as suggesting some kind of self-recognition. Parrots, although failing the mark test, can use mirrors to locate hidden food, suggesting some appreciation of the properties of the mirror, or maybe just instrumental conditioning.
Finally, horizontal reflective surfaces may be more naturalistic (e.g. pools of water) than the vertical ones (e.g. windows), and thus less likely to elicit the aggressive conspecific-directed behaviour; Kusuyama et al. found that the crows behaved less aggressively to a horizontal than to a vertical mirror.
... furthermore your scepticism of the group-selection / altruism explanation is of course completely justified (did you do A level biology? I didn't so forgive me if I'm wrongly assuming ignorance of evolutionary theories), and your idea that they're trying to get at food behind the glass is perhaps the most plausible of the three...
So that's clear, isn't it?
