Did you know that budgerigars, Melopsittacus undulatus -- erroneously known as "parakeets" in the United States -- can see UV light? Did you know that female budgerigars rely on the UV reflectance to judge the quality of potential mates? This is a fascinating little trailer about wild budgerigars from the Nature program Parrots in the Land of Oz, which airs on PBS on 19, 20 and 21 October [1:43]
I was confused when the narrator mentioned the bit about how budgies can see UV light. Can't nearly all birds? I read an article a few years ago in Science that explained how the common ancestor of birds and mammals had 3 cones, then birds evolved a fourth type of cone that enabled them to see UV light, whereas mammals lost one and only primates evolved one back giving them three about. Hence the misconception about why dogs are color blind -- they can see colors, just not as many because they only have 2 kinds of cones.
So basically, what I don't get is why the announcer said this specifically about budgies like they have a magic power that is unique to them in the bird world? Any thoughts?
well, it is likely that most (all?) birds can see UV light, but we cannot say that for sure because we have not investigated this for all bird species. but nonetheless, most people are unaware of birds' ability to actually see UV light reflectance, unless they've watched The Life of Birds or this program.
I read an article a few years ago in Science that explained how the common ancestor of birds and mammals had 3 cones,
But other than primates, almost all modern mammals are dichromates (2 types of cones). So I'm skeptical of the idea that the common ancestor of birds and mammals had 3 types of cones.
Here are some links:
And smell, too!
Skepticism is good.
The theory to explain this is that our mammalian ancestors spent a great deal of time living underground to avoid unfavorable atmospheric conditions, while the ancestors of birds remained above ground. The birds then, found it advantageous to have a fourth cone, while mammals in the dark really had no need for three cones and lost one with out fitness-related consequences.
But *I* can see UV light. What does this mean?