Endangered Hawaiian Hawk may be De-Listed

[Mitzi M]

Mdd - Your question is a very good one that science has not yet satisfactorily answered. The hawks are territorial and the size of each individual or mating pair's territory depends on the resources available there. So a hawk on say the relatively barren more recent lava flows of Kilauea or in lower Ka'u may have a larger territory than one up near Hakalau. How big are they? I don't think enough work has been done to know.

In the original recovery plan produced in 1984, all information about the hawk's estimated population came from the PhD dissertation of a person named Griffin. Griffin estimated there were 1,400-2,500 birds, however there is no mention anywhere of the methods used to come up with this number and his dissertation was never published. This is pretty unusual for science - and while I have no way to know, it basically says Griffin could have just dreamed it up whilst sipping a Mai Tai.

But this didn't stop the USFWS from using these numbers to come up with a recovery goal of 1,500-2,500 birds - according to the numbers used - pretty much the number that was supposedly already here. Maybe that was to make their job easy?

I got this information from the Federal Register-vol.73 No.152 (The proposal to de-list.) It says plainly that "No explanation for the recovery goal of 1,500-2,500 birds was provided, but these #'s were presumably based on Griffin's (1985)..."

Presumably? Again - kinda unusual for science not to keep track of things.

Bottom line, by their own estimation the USFWS says 58.7% of the 'Io's habitat is in private hands and so is shrinking with every big tree that goes down. We know that this trend will continue, at some rate anyway, and will probably not reverse itself in the foreseeable future. So we still need to try and protect these birds and the native forests with them.

Come out to the meeting if can. Tell your friends.
We can't get it back when it's gone.

Aloha,
Mitzi

[dakine]

quote:

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Originally posted by mdd7000

....Would they attack Nene in that event?

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I think there is usually some order to things.. larger attack smaller.. as with the Io rats are a good food source. We have a breeding pair of Io that have had a single chick every year for the last 10+ yrs. living nearby. With each young Io (every spring) we get a period.. usually about a year.. between when they fledge (first take flight) to when they move on. We have had them and their parents hunting on our property all the time. I do not worry about our cats, but have seen many a smaller bird become their prey. And see rats being hauled to their nest regularly.

And, since the opening of the new vent at Halemaumau, a flock of Nene have also come to roost. This is way unusual.. Nene in the depth of the rainforest rather than on the drier desert side of Kilauea.. and a completely awe inspiring event. I have seen Io shadow Nene, but never have seen them attack. Nene hang in groups, fly in formation, which I suspect is a defensive maneuver. Though I suspect, from the feeling I got watching that lone Io shadow (flying higher and a little behind) the Nene that were there to be a weakened lone Nene an Io might take a shot at it. Rich pickings (there is no limit to the Io's food source here) or not. But, all things being equal, I suspect the Io would rather go after easier, smaller prey. And, seeing Io everywhere, including living in Hilo proper, I suspect they are pretty adaptable, and of course rats, mice, and smaller birds are everywhere.

[mdd7000]

dakine - nice explanation! Thanks! So the I'o could eat Nene chicks, right?

You really need to set up a webcam.

[dakine]

quote:

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Originally posted by mdd7000

So the I'o could eat Nene chicks, right?

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Sure, but considering that the Nene lay their eggs on the ground, so could a mongoose or a rat