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Ronald G. Arsenault
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Hi Randy and All
Seems to me there might be a lot of variation
in the response of owls to calls. or just plain calling.
It would be interesting but hard work to do a route every night
for a month to see what the variation in the call rate would be.
Say within weeks and between weeks.
Not as much fun as speculating though!
We haven't done our route yet but it has been pretty consistant
at 2 pairs of owls. Only Barred - maybe this year we'll be lucky.
Enjoy the spring
Paul
=A0
--- On Wed, 4/17/13, Randy Lauff <randy.lauff@gmail.com> wrote:
From: Randy Lauff <randy.lauff@gmail.com>
Subject: Re: [NatureNS] Lapland/Laconia Owl Monitoring Route
To: "NatureNS" <naturens@chebucto.ns.ca>
Received: Wednesday, April 17, 2013, 5:51 AM
Interesting discussion.
Of the owls I'm most familiar with, only the Boreal is known to stop callin=
g once nesting has commenced. I do not know if anyone has followed nesting =
Barred Owls, for example, and recorded calling rates prior to, and after th=
e commencement of nesting.
One year, I had a Saw-whet calling quite late, even =A0during the daytime. =
My impression was he was the nerd of the Saw-whet world, and the ladies wer=
en't too impressed with him! Eventually though, I found the cavity from whi=
ch he was calling (not an easy task with one ear not working well) and late=
r, he and a lovely young lady raised one young. The daytime calling stopped=
, and I think the night time calling went down significantly.
Surveys which use many people, whether volunteers or paid, have many=A0inhe=
rent=A0difficulties. We're all using the same soundtracks, but not all the =
same players and speakers. We don't all have the same ability at (a) hearin=
g or (b) identifying the owls. Estimating the distance from which an owl is=
calling (is it facing you, or facing away...is the sound coming through th=
e woods or across a field, is there wind? run off noise?) can be daunting. =
Large numbers of replicates (many routes, many stations, many years), tend =
to smooth out some of the bumps, but the data must still be used with cauti=
on.
Randy
_________________________________
RF Lauff
Way in the boonies of
Antigonish County, NS.
On 17 April 2013 09:10, Ronald Arsenault <rongarsenault@gmail.com> wrote:
Hello Patricia,
Very interesting question and one to which I do not know the answer. =A0I s=
hould also point out that the sentence which prompted your question was my =
interpretation of what Scott had said, so I will attempt to clarify. =A0Ple=
ase note that this is based on a=A0conversation=A0which happened three to f=
our years ago.
As I recall, Scott found during his monitoring that owls were less vocal wh=
en tending nests with eggs or young than was the case during years when the=
y 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 cal=
ls =3D more birds", which his monitoring showed was not the case.
At the time, his intent was to discuss his findings with Bird Studies Canad=
a to make them aware of his concern. I do not know what eventually happened=
. =A0Perhaps the "silent listening" was implemented as a result?
I do not recall Scott going into detail re owl behaviours that would explai=
n this. =A0I would suggest though, that there are a number of factors which=
are likely to affect the calling rate, including the response rate to play=
back, of owls. However, I would not expect complete suppression except for =
cases of severe starvation. =A0Some factors which likely affect the calling=
rate of owls (with or without stimulation by playback) are: =A0timing - ho=
w 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 =3D less time for call=
ing; distance from nest - the closer the playback to the nest, the likelier=
the response; density of the owl population could even play a role; perhap=
s 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. =
=A0Perhaps 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,
=A0=A0=A0=A0=A0=A0=A0=A0This is an interesting observation.=A0 But it leave=
s me with a question.=A0 Are "owls which have settled down with nesting dut=
ies" less likely to call AT ALL, or just less likely to respond to a record=
ing?=A0 The ":silent listening" portion of the survey, which is the first p=
art, preceding the broadcast of recorded calls, is considered the most sign=
ificant part of the survey, I believe. {In some parts of the country the of=
ficial survey protocol doesn't use broadcast calls at all.)=A0=A0 So are ow=
ls which are freely calling, i.e. when unprovoked, more likely to be unsucc=
essful breeders than those who remain silent?
=A0=A0=A0=A0=A0=A0=A0=A0 Suzanne Borkowski and I usually detect many of the=
owls we find during those first two minutes of the survey; if they react t=
o the broadcast calls later, it gives us more time to confirm distance and =
direction etc.=A0=20
=A0=A0=A0=A0=A0=A0=A0=A0Cheers,
=A0=A0=A0=A0=A0=A0=A0=A0Patricia L. Chalmers
=A0=A0=A0=A0=A0=A0=A0=A0Halifax
=A0=A0=A0=A0=A0=A0=A0=A0
At 02:16 PM 16/04/2013, you wrote:
Hello Randy,
This may in fact be good news.=A0 Scott Makepeace, NB Dept. Nat. Resources =
biologist who monitors owls, told me that his work has revealed that the re=
sponse rate of owls is actually inversely related to their nesting success,=
especially with Barred Owls, if I remember correctly.=A0 In other words, o=
wls which have settled down with nesting duties are much less likely to res=
pond to a taped call than are owls who are either looking for a mate or who=
se 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 bare=
ly 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 perple=
xing.
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 stop=
s.=A0=A0 We missed out on owls interestingly on two of the stops that we us=
ually get them.=A0 One of these stops now has a trailer at the location, so=
that could be the reason.=A0 The other stop we always have wood frogs and =
sp