Hi Laura,
I wanted to follow-up on your question regarding Kestrels in Ohio. After the last discussion on the listserv about the status of this species in the state I started looking at some Audubon Christmas Bird Count data to see if I could discern any patterns in population trends.
I looked at Kestrel data (birds per party hour) from almost all of the CBCs in Ohio between 1960 (61st count) and 2005 (106th count). Using this data I was able to come up with a statewide trend for Kestrels in the state.
I went through each count in the state and categorized them into one of four categories based on a rough estimation of the predominant habitat type within each count circle. The four categories were rural, urban, areas undergoing sprawl, or communities that have pretty much remained the same.
I then looked at Kestrel trends for each of the four habitat types and compared them against the statewide trend.
My rough analysis of CBC data suggests that over-wintering Kestrels are increasing statewide. However, they're increasing more in rural areas, and slightly more in communities that have not undergone much change. They seem to be decreasing pretty dramatically in urban areas. In communities undergoing change (i.e. development) Kestrels seem to be leveling out.
Because over-wintering Kestrels seem to be increasing, based on this study, in rural areas irrespective of region of the state or agricultural type (which I did not examine) would potentially suggest that crop type or herbicide use may not be a factor.
Again, this was just a rough analysis without any special statistical analysis to determine significance, etc., and it's only looking at birds recorded during the Christmas Bird Count period (mid-December to early January). I can send copies of the graphs in a microsoft word document to anyone who is interested in seeing them for themselves.
Hope this helps answer your question a little,
Casey
-----Original Message-----
From: Ohio birds on behalf of [log in to unmask]
Sent: Fri 1/26/2007 7:15 PM
To: [log in to unmask]
Cc:
Subject: [Ohio-birds] Am. Pipets in Holmes Co. & some thoughts on Kestrel populations
Returning from our cottage in Coshocton Co. today, Tim & I drove some back
roads in Holmes Co. & were lucky enough to find a flock of 10-20 American
Pipits feeding on some freshly spread manure. They were on CR 58 just west of
the intersection with T122 & T128. (Delorme 60A4--right above the"N" in
Mechanic Township). Also saw a Rough-legged Hawk on T157, just outside of Charm
(DeLorme 51D4).
While driving these roads we saw quite a few kestrels, more than we have
seen in similar habitat in other rural areas of Coshocton, Stark, Summit &
Portage counties. (The counties we drive most often). Remembering the discussions
we have seen on this list-serve regarding possible kestrel population
declines, we wondered what might be different in Holmes Co. Could the use of
Round-up Ready crops that has become so popular in recent years be a factor? It
is quite likely that these Round-up treated seeds are not used as heavly on
Amish farms. These treated seeds result in less weeds, which should mean less
insects & therefore less food for kestrels. Or could the insects that are
present have toxins in them from the treated seeds? Would any of this
hypotheses result in kestrels either dying or moving to other areas, such as Holmes
Co.? Has anyone else noticed more kestrels in some counties that have less
soybean/corn row crop production where Round-up Ready seed is more prevelant?
Laura Dornan
Louisville, Stark Co.
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