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<dd><font size=4>An interesting evening for running this route with o
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Hello Patricia,
Very interesting question and one to which I do not know the answer. I
should also point out that the sentence which prompted your question was my
interpretation of what Scott had said, so I will attempt to clarify.
Please note that this is based on a conversation which happened three to
four years ago.
As I recall, Scott found during his monitoring that owls were less vocal
when tending nests with eggs or young than was the case during years when
they did not nest or the nesting was not successful. His concern was that
the results of the owl survey were being (or would be) interpreted as "more
calls = more birds", which his monitoring showed was not the case.
At the time, his intent was to discuss his findings with Bird Studies
Canada to make them aware of his concern. I do not know what eventually
happened. Perhaps the "silent listening" was implemented as a result?
I do not recall Scott going into detail re owl behaviours that would
explain this. I would suggest though, that there are a number of factors
which are likely to affect the calling rate, including the response rate to
playback, of owls. However, I would not expect complete suppression except
for cases of severe starvation. Some factors which likely affect the
calling rate of owls (with or without stimulation by playback) are: timing
- how far into the nesting season are the owls when the survey is done;
whether or not the bird is paired - single birds would be more motivated to
call; prey density - more time needed to catch enough prey = less time for
calling; distance from nest - the closer the playback to the nest, the
likelier the response; density of the owl population could even play a
role; perhaps even the age of the birds could also be a factor - well
established pair vs first time nesters?. These are just some of the factors
which come to mind, and of course, these are not necessarily independent of
each other. Perhaps others (Randy?) can add to or correct the above.
Hope this helps,
Ron
On Tue, Apr 16, 2013 at 10:56 PM, P.L. Chalmers
<plchalmers@ns.sympatico.ca>wrote:
> Hi Ron,
>
> ** **This is an interesting observation. But it leaves me with a
> question. Are "owls which have settled down with nesting duties" less
> likely to call AT ALL, or just less likely to respond to a recording? The
> ":silent listening" portion of the survey, which is the first part,
> preceding the broadcast of recorded calls, is considered the most
> significant part of the survey, I believe. {In some parts of the country
> the official survey protocol doesn't use broadcast calls at all.) So are
> owls which are freely calling, i.e. when unprovoked, more likely to be
> unsuccessful breeders than those who remain silent?
>
> ** ** Suzanne Borkowski and I usually detect many of the owls we
> find during those first two minutes of the survey; if they react to the
> broadcast calls later, it gives us more time to confirm distance and
> direction etc.
>
> ** **Cheers,
>
> ** **Patricia L. Chalmers
> ** **Halifax
>
> ** **
>
>
> At 02:16 PM 16/04/2013, you wrote:
>
> Hello Randy,
>
> This may in fact be good news. Scott Makepeace, NB Dept. Nat. Resources
> biologist who monitors owls, told me that his work has revealed that the
> response rate of owls is actually inversely related to their nesting
> success, especially with Barred Owls, if I remember correctly. In other
> words, owls which have settled down with nesting duties are much less
> likely to respond to a taped call than are owls who are either looking for
> a mate or whose nesting attempt has failed.
>
> Hope this cheers you up!
>
> Ron
>
>
> On Tue, Apr 16, 2013 at 11:30 AM, Randy Lauff <randy.lauff@gmail.com>
> wrote:
>
> Krista and I did the Fairmont (Ant. Coi.) route last night. Frogs were
> barely an issue as it was about -3 oC the whole time. Three or four years
> ago, I got a dozen (?) or so Barreds, GHOW and S'whets. Last year, skunked.
> This year, under similarly ideal conditions as last year...skunked. Very
> perplexing.
>
> Randy
>
> _________________________________
> RF Lauff
> Way in the boonies of
> Antigonish County, NS.
>
>
> On 16 April 2013 01:13, James Hirtle <jrhbirder@hotmail.com> wrote:
>
> An interesting evening for running this route with owls on 8 out of 10
> stops. We missed out on owls interestingly on two of the stops that we
> usually get them. One of these stops now has a trailer at the location, so
> that could be the reason. The other stop we always have wood frogs and
> spring peepers so loud that it is unbelievable, but by that point the
> temperature had dropped to around freezing. Wood frogs and spring peepers
> were at the first five stops and I suspect we would have heard them on all
> stops had the temperature not dropped. As the temperature dropped the owls
> seemed to become less vocal. I don't know if any studies have been done in
> respects to this observation or not. In all we had 10 barred owls. Most
> of the owls all except for the first stop where there were three, two of
> which were seen, were all more distant than is the norm on this route.
>
> James R. Hirtle
> Bridgewater
>
>
>
>
>
> --
> Ronald G. Arsenault
> Moncton, N.B.
>
--
Ronald G. Arsenault
Moncton, N.B.
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<div dir=3D"ltr">Hello Patricia,<div><br></div><div style>Very interesting =
question and one to which I do not know the answer. =A0I should also point =
out that the sentence which prompted your question was my interpretation of=
what Scott had said, so I will attempt to clarify. =A0Please note that thi=
s is based on a=A0conversation=A0which happened three to four years ago.</d=
iv>
<div style><br></div><div style>As I recall, Scott found during his monitor=
ing that owls were less vocal when tending nests with eggs or young than wa=
s the case during years when they did not nest or the nesting was not succe=
ssful. His concern was that the results of the owl survey were being (or wo=
uld be) interpreted as "more calls =3D more birds", which his mon=
itoring showed was not the case.</div>
<div style><br></div><div style>At the time, his intent was to discuss his =
findings with Bird Studies Canada to make them aware of his concern. I do n=
ot know what eventually happened. =A0Perhaps the "silent listening&quo=
t;