All,
Sorry I missed the call today (I got side-tracked). Amy is correct that Laura
and I have some information on detection probability. And, as we were warned,
detectability in WV and VA is very low. Chris, I would be glad to chat some
more about her results on the phone, which would probably be easier than typing
out an e-mail. We can set-up a call without including everyone on the listserve.
Also, I've been meaning to ask the group about the decoys I sent around. Did
anyone deploy them last summer and have any success?
I'll try to be on the call next time!
Christopher M. Lituma, PhD
Assistant Professor
Certified Wildlife Biologist®
Davis College, Division of Forestry and Natural Resources
West Virginia University
1145 Evansdale Drive
310B Percival Hall
Morgantown, WV 26506
Office: (304) 293-7473
Cell: (215) 378-2747
Email: cml0017@xxxxxxxxxxxx
-----Original Message-----
From: eloshwg-bounce@xxxxxxxxxxxxx <eloshwg-bounce@xxxxxxxxxxxxx> On Behalf Of
Amy Chabot
Sent: Thursday, February 13, 2020 11:49 AM
To: eloshwg@xxxxxxxxxxxxx
Subject: [eloshwg] Re: point counts
Hi all,
I'm hoping (hint, hint) that Chris Lituma, or perhaps more so his student Laura
Graham, will be able to chime in here as "detectability" was part of her
research, and she did base methodology on point counts, but then added in time
after for looking for shrike.
From my own experience, there are a few factors:
1. LOSH don't tend to vocalize and many point counts (e.g. BBS), in my
experience are more focused on auditory detection 2. Length of time for the
point count, wrt shrike detection, is important. Again, in my limited
experience, many point count methods are too short for shrike. I usually wait
20 minutes, scanning with binoculars, before I move on to another site/point
during surveys.
3. Point counts are better when you have a nice open habitat, but not too wide
open. i.e. sometimes it's more effective for shrike to walk through the
habitat, stopping to scan every now and then for a length of time, than
standing in one spot.
4. Given 3, it matters if the point count is limited or unlimited distance 5.
The reliability of detecting a shrike varies considerably based on stage of
reproduction. It can also vary based on weather (yes, I know "duh" - but e.g.
in high wind, shrikes often hide or don't hunt from as high up).
6. There are simply times when shrike don't want to be found - thus, my "go to"
(and the ON survey protocol lays all this out in much more concrete and likely
understandable way), is to visit a site at least 3x, at least a day or so
apart, and preferably throughout the season, before I mark shrike as "absent"
or a site as unoccpuied. Seems that if they are going to be found, you'll see
them, if you wait 15 or 20 minutes (often less but not always). Whereas, you
can also spend hours on one day and not see them, then, go back a day later,
and, there they are.
7. Road-side versus on-site are considerations (not necessarily related to
point count methods, but to survey method more generally, and has to do with
visibility, etc.) 8. Just an fyi, there has been some work (again, Laura can
add more specifics from recent work) as to whether call playback helps.
9. Finally, the Survey123 App being developed includes a "time to first
detection" specifically to help us figure out/adjust for detectability.
Hope this helps. Happy to talk by phone!
Amy
________________________________________
From: eloshwg-bounce@xxxxxxxxxxxxx [eloshwg-bounce@xxxxxxxxxxxxx] on behalf of
Christopher Hill [dmarc-noreply@xxxxxxxxxxxxx]
Sent: Thursday, February 13, 2020 11:31 AM
To: eloshwg@xxxxxxxxxxxxx
Subject: [eloshwg] point counts
Hi all,
There was a strong statement on the phone call today (and I don’t recognize
everyone’s voice so I don’t know who I am quoting): “We’ve all come to the
conclusion that point counts are unreliable for detecting shrikes.”
That surprised me! I would have thought that shrikes, though they don’t
vocalize reliably, would be very detectable because of open habitats and
conspicuous perching.
Exactly how reliable or unreliable point counts are is something I’m interested
in, and potentially I could add some data to the discussion, but I guess I
should catch up with where the discussion currently is, first. I didn’t want
to sidetrack the call but I would very much like to follow up on this point, so
if anyone could provide any pointers to written stuff on this point, or is
willing to field a phone call from me, or is willing to put together a
paragraph or some bullet points on this consensus I would be very grateful.
Anybody?
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