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I was reading about this remarkable birdy and it came over here, and it did a thing called adaptive radiation. This is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches. Starting with a recent single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits.
So basically, some honeycreepers came over here, and filled almost every ecological niche on the island that a bird can! As for my question, it is this: why didn't the honeycreeper evolve to eat fish? Hawai'i has extremely plentiful fish. It would seem to be a seabirds paradise, but there are none here.
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Glass#.. the honey-creepers are radiated from finches... as in the finch diversity Darwin chronicled in the Galapagos. I am pretty impressed that they got from hard billed seed-eaters to the woodpecker like the 'Akiapola'au (this bird has a hard hammer like lower bill & a more flexible, probing upper bill)
https://www.sciencedirect.com/science/ar...2211011894
ETA: also remember that there were far more birds here than there are now including large flightless birds, giant goose species, & many more seabirds than we experience here today... think of the NW Hawaiian island & the seabird populations there..
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That's true about the birds, there used to be all kinds of strange birds here in Hawai'i. I guess that there are limits to the basic genetic potential of one species, even with adaptive radiation. Also, yeah, to make it from a finch to a woodpecker is pretty awesome
thanks for the reply Carey, that's exactly what I was looking for.
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why didn't the honeycreeper evolve to eat fish?
Probably because there were easier sources of nourishment so no need.
As with the flightless birds, even flying is abandoned when no need.
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Eating fish from the ocean requires a lot more specialization than even what has gone on in the honeycreeper radiation, which mostly involves the shape of the bill. Seabirds like albatrosses, boobies, and pelicans are all part of a big group of mostly-aquatic birds. None in the big group that includes passerines (perching birds, including finches) have adapted to the ocean, and only a few ever dive in water at all (kingfishers and some hawks). It would probably be easier to adapt to catching fish in streams, like kingfishers, but the only native freshwater fish are oopu which spend their time on the bottom, and the streams are mostly fast-flowing and shallow, rather than the deeper, slow-moving water that kingfishers dive in.
