Ivory-bill Publications

[MMinNY]

I don't think this very interesting Defenders of Wildlife commentary on the Draft Recovery Plan has been posted here. While it is a few years old, and the Recovery Plan is now complete, it's still thought-provoking:

http://www.defenders.org/resources/p...overy_plan.pdf

I was particularly intrigued by point 8 on page 12.

[fangsheath]

This offering mirrors many of my own concerns about potentially unwarranted assumptions and overemphasis on forage. The author expresses some doubts that roost/nest tree availability might be limiting, since data on smaller woodpeckers indicates a surplus of suitable sites. However, it is important to realize that the situation for a large woodpecker with a long nestling period is inherently more tenuous. Nest predation issues may be critical, and sites that provide good protection may be quite limited. Why do pileateds nest in power poles hundreds of feet from available forage, exposing themselves to aerial predators? Surely if there are plenty of suitable nest trees in the forest they would nest in the midst of good forage.

[MMinNY]

I think the jury's out on why PIWOs nest in utility poles. While your rationale makes sense, there are other possible explanations. Dennis's paper on the subject indicates that PIWOs sometimes choose utility poles even when suitable nest trees are abundant; however, it does seem like a stretch to extrapolate from smaller woodpeckers when it comes to potential nest or roost sites.

I didn't mean to be cryptic in my reference to the Defenders of Wildlife commentary. I think the analogy between the Black-backed and Three-toed Woodpeckers and the IBWO may be very apt, especially in light of some aspects of their morphologies. The Picoides species seem to be highly specialized, likely more so than the IBWO.

[fangsheath]

But in a sense that is precisely my point. The question of suitability has not been properly addressed from a nest predation standpoint. Why on earth does a small woodpecker like the red-cockaded nest in huge live trees? Aren't snags "suitable"? In this case the incongruity almost forces a conclusion. But in the case of pileateds and others, the predation issue has never been properly addressed.

I realize it's anecdotal, but I can't help noticing that pileateds seem abundant in a forest with many large cypress snags and few sizable hardwoods. By contrast, they are rare in a forest with abundant carpenter ant sign but few really large snags. Yet I could easily imagine someone looking at the latter and concluding that there are plenty of "suitable" trees. Most large cavity trees that I have examined have been >30 in DBH. The larger the tree, the more space it tends to command, thus making it harder for rat snakes to reach it from adjacent trees, particularly after it dies.

I think you are right about the relevance of these other species, and I think the author is right in emphasizing increasing rotation and other overall habitat issues over local forage enhancement. I think we are moving in the right direction, but I'm still not convinced that many forest managers how much time is still required for most forests to become genuinely mature.