[TN-Bird] thoughts on Bill Pullman's BBS data graphs of Wood Duck and Black-throated Green Warbler
- From: David Vogt <dfvogt41@xxxxxxxxx>
- To: tn-bird@xxxxxxxxxxxxx
- Date: Wed, 12 Oct 2011 19:13:06 -0500
First, thanks to Bill for putting these graphs together. Very helpful to
see the TN data reflected in graph form. I'd like to speculate on causes
for the apparent declines indicated for Black-throated Greeen Warblers and
for Wood Ducks. The obvious explanation for the Black-throated Green
Warbler decline is the precipitous die-off of the hemlocks in east Tn due to
the Hemlock Wooly Adelgids.
As for Wood Duck numbers: I've noticed pretty a drastic decline of Wood
Duck numbers on the lake at Fall Creek Falls State Park in the last 4
years. This decline coincides with the appearance of river otters on the
lake. I wonder if river otters are taking a toll on ducklings which would
account for the numbers reflected on BBS routes. It looks as if the decline
in TN WODU numbers pretty closely follow the dates of TN Wildlife Resourses
Agencies project to reintroduce river otters to the state.
Again, these are only theories and, I do not mean to suggest that river
otter should not have been reintroduced but thought I'd suggest this
explanation.
Thanks again to Bill for his efforts,
David Vogt, Park Naturalist Fall Creek Falls State Park
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