https://www.nbcnews.com/science/environment/kill-barred-owls-to-save-endangered-spotted-owls-proposal-rcna129926
There have been several news articles about the US Fish and Wildlife
Service wanting to start killiing barred owls on the West coast because
they are out competing spotted owls. For some reason they blame human intervention, but that is stupid. The last interglacial the same thing
likely occurred and the spotted and barred owls likely got together
again. The barred owl used the Canadian forests to get to the West
coast. This region would have been impassable during the last ice age,
and would have separated the two species, but during the interglacials
the forests would return.
What they should likely do is look for previous interbreeding events in
the two species. They know that the two species can interbreed, and it
has likely happened before when the two populations are no longer
separated by ice. It may just be that the Northern spotted owls were
just not destined to survive the next ice age, and that this is how they
have maintained their current range for the last million years when the
cold intervals got longer. They have had to survive cold intervals over
100 thousand years long for the last half million years, and they likely
did it where they have large populations in the Southwest.
My take is that this is just natures way of making sure that the best
genetics survive into the future. Where are the less fit spotted owls
going to survive the next cold period? Is their population genetically
healthy enough to survive another cold period? For all we know it was
the spotted owl that made the continental migration last time and
invaded the barred owl territory, and their genetics are coming back to
take over the West coast population that survived as small isolated
populations during the last cold period.
What we need are large populations of genetically healthy individuals.
Small populations are likely destined for extinction. They have to
assess how different spotted owls are from barred owls and, my guess is
that they are pretty closely related (this has probably happened before
in previous interglacials). If they think that the spotted owls have
genetic adaptations that would help the barred owls they can start a
hybrid breeding program and make sure that spotted owl genetics have a
future in the Northwest.
From what I've seen before these two species are pretty closely
related, and my guess is that they have evidence of previous
interbreeding events in their genomes, but no one wants to look. One
paper that I saw had the Northwest barred owls more closely related to
the spotted owls than the East coast barred owls. It looked like they
might have had around 6% introgression from Spotted owls (the non hybrid
West Coast barred). The current known hybrids were about halfway
between spotted and West coast Barred. The paper did not comment on why
the West Coast barred seems to have some spotted owl genetics, they only
tried to claim that they seem to be a divergent unsampled sub population
of midwest or East coast Barred owls that somehow made it through Canada
to the West coast.
We should just let this sub population of barred owls expand and
increase their population size. For all we know all the other sub
populations are headed for extinction, and this population has the
genetics to make it into the future. It will have less of a chance to
make it into the future if we reduce it's population size in order to
save a population that is already failing. They are talking about
killing a half a million animals. For a noninvasive species (this has
likely happened before) it would be stupid to reduce the size of a
healthy thriving population when we know that in the next ice age their population will be decimated and they will need all the genetic
variation that they have to survive another hundred thousand years of
reduced habitat.
Ron Okimoto
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