[TN-Bird] Re: Loggerhead Shrike (Robertson Co.)
- From: Tony Lance <tonylance@xxxxxxx>
- To: tn-bird@xxxxxxxxxxxxx
- Date: Sun, 18 Oct 2009 14:07:31 -0400
Sorry to bombard the list with repeated posts, but some of you might be
interested in this (and others of you probably already knew it). Out of
curiosity about the possible association between shrikes and cattle I did a
quick Google search and found the abstract to an interesting paper. It appears
that at least in Austria shrikes are found most often on grazed farmland. It
says:
"In 1997 and 1998, we investigated the habitat use of Red-backed Shrikes
breeding on farmland in Carinthia, southern Austria. We devised an objective
census technique to obtain relative measures of shrike abundance and habitat
coverage along 35 1 km transect belts, 60 m in width, positioned randomly
throughout an area of 100 1 km squares. Shrike abundance was related to habitat
variables by means of general linear models. Bivariate models suggested that
Red-backed Shrikes were positively associated with grassland grazed by
livestock, fence-lines and scattered trees and shrubs, but negatively
associated with arable land and grassland that was not grazed. A model
constructed with the help of forward selection indicated that shrike abundance
was most strongly associated with a mixture of grazed grassland and scrub.
Shrike abundance increased with grazed grassland cover. When the cover of
grazed grassland was kept constant, shrike abundance increased with scrub cover
up to between 10 % and 15 % cover, and declined thereafter. We tested the
validity of the model using data from a further 20 transects, collected in
1998. The number of shrikes predicted under the model was significantly
positively correlated with the number of shrikes recorded."
http://www.springerlink.com/content/9l355162537317l5/
Tony Lance
Springfield, TN
On Sunday, October 18, 2009, at 01:32PM, "Tony Lance" <tonylance@xxxxxxx> wrote:
>It occurred to me after the previous post in which I mentioned Loggerhead
>Shrikes nesting on our neighbor's dairy farm in years past that the last two
>times I've seen shrikes in this area have been on or very near dairy farms.
>The pair in Logan Co., Ky. were on a dairy, and the one today was within sight
>of one. I imagine it's a coincidence, but I'm curious if anyone else has
>noticed an association with dairies or cattle.
>
>Tony Lance
>Springfield, TN
>
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