From: Dave Leatherman
Sent: Sunday, April 03, 2011 11:10 PM
To: [email protected] ; COBIRDS
Subject: Re: [cobirds] Re: Douglas County American Three-toed Woodpecker
Steve, Andy, et al,
I think you guys are both right. I haven't been in that area in several years,
but it (Jarre Canyon and the whole Hayman Fire area) over the last 20+ years
has had lots of budworm, Douglas-fir Tussock Moth, Douglas-fir Beetle,
Douglas-fir Pole Beetle and other bark beetles (called "engravers") in the
genus Scolytus. Usually what happens is one or both of the defoliators (the
moths) chew the trees' needles for a few years, the affected trees become
weakened (as indicated by top-kill), and one or more of the beetles finish them
off. Usually the Douglas-fir Beetle (Douglas-fir equivalent of the Mountain
Pine Beetle) hits the bigger diameter stems and the pole beetle and engravers
are in the stems smaller than 10 inch in diameter. My bet would be a complex
of insects is involved in the entire decline and death of the stand but the
presence of the woodpeckers indicates bark beetles and/or wood boring beetles
in the dead trees. If the needles on these trees that weren't moth-chewed
(i.e., missing) are red, that would indicate the death is recent enough to
indicate the woodpeckers are probably after bark beetles. If the tree crowns
are pretty much needleless and gray, indicating the trees died two or more
years ago, I would guess the woodpeckers are after the larvae of larger,
secondary beetles like wood borers. I often refer to the borers that show up
in the second wave of succession (riding the coat-tails of whatever it was that
killed the tree) as "lawyers" - they are at the accident but didn't do it. If
anybody goes back to this area, I'd be interested in what you think the
woodpeckers are after (bark beetles would be right under the bark and their
predation would be indicated by several shallow patches of pecking, extraction
of borers would usually require deeper excavation of the outer rings of wood
and be indicated by fairly widely-spaced gouges).
Dave Leatherman
Fort Collins
From: Steve Stachowiak & Melody Egge
Sent: Sunday, April 03, 2011 9:57 PM
To: [email protected]
Subject: [cobirds] Re: Douglas County American Three-toed Woodpecker
Cobirders,
I thought that I would add that the "beetle kill" area as it was referred to by
Andy is most likely attributable to Western Spruce Budworm. The large stand of
dead defoliated trees is comprised of Douglas-fir while the Ponderosa Pines in
the immediate vicinity remain in healthy condition. I visited this location on
Saturday morning but had no luck with the American Three-toed so it is nice to
know that they are indeed still in the area. There are also Williamson's
Sapsuckers drumming in the stand across the road to the south.
Good Birding,
Steve Stachowiak
Highlands Ranch, CO
--
You received this message because you are subscribed to the Google Groups
"Colorado Birds" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/cobirds?hl=en.
--
You received this message because you are subscribed to the Google Groups
"Colorado Birds" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/cobirds?hl=en.
