"If we ask ourselves why this or that species is rare, we answer that something is unfavourable in its conditions of life; but what that something is, we can hardly ever tell" Charles Darwin, Origin of Species 1st edition (on Kindle)
Do we understand that now? Generally, more or less. Specifically, more or less. Species restricted to smaller islands are necessarily rare and most birds that have gone extinct were island birds. Being high up on the food chain in terrestrial ecosystems means you have lower density. Oceanic ecosystems may support higher densities of predators - I think of all the alcids (auks, guillemots, puffins, etc) and boobies (including gannets). Being a habitat specialist when that habitat is rare makes you rare. You'll often just see habitat specialist listed but I know many habitat specialists that are abundant - it's just that habitat is abundant. Then there are a number of confounding variables that interact with the primary causes of rarity. Nesting location, susceptibility to disease, being tasty (moas), your pelage or feathers looking good, etc have all been implicated.
Running out of novel pictures. Sad really. Means I'm not going places are even exploring the places around me.
Ascocarp? fungus from Nescopeck State Park
"If we ask ourselves why this or that species is rare, we answer that something is unfavourable in its conditions of life; but what that something is, we can hardly ever tell" Charles Darwin, Origin of Species 1st edition (on Kindle)
Do we understand that now? Generally, more or less. Specifically, more or less. Species restricted to smaller islands are necessarily rare and most birds that have gone extinct were island birds. Being high up on the food chain in terrestrial ecosystems means you have lower density. Oceanic ecosystems may support higher densities of predators - I think of all the alcids (auks, guillemots, puffins, etc) and boobies (including gannets). Being a habitat specialist when that habitat is rare makes you rare. You'll often just see habitat specialist listed but I know many habitat specialists that are abundant - it's just that habitat is abundant. Then there are a number of confounding variables that interact with the primary causes of rarity. Nesting location, susceptibility to disease, being tasty (moas), your pelage or feathers looking good, etc have all been implicated.
Running out of novel pictures. Sad really. Means I'm not going places are even exploring the places around me.
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| Ascocarp? fungus from Nescopeck State Park |
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