next message in archive
next message in thread
previous message in archive
previous message in thread
Index of Subjects
>> spring peepers so loud that i
--f46d044401ca21df5a04da8f5ac4
Content-Type: text/plain; charset=ISO-8859-1
You said it better than I would have.
All the best,
Ron
On Wed, Apr 17, 2013 at 9:51 AM, Randy Lauff <randy.lauff@gmail.com> wrote:
> Interesting discussion.
>
> Of the owls I'm most familiar with, only the Boreal is known to stop
> calling 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 the commencement of nesting.
>
> One year, I had a Saw-whet calling quite late, even during the daytime.
> My impression was he was the nerd of the Saw-whet world, and the ladies
> weren't too impressed with him! Eventually though, I found the cavity from
> which he was calling (not an easy task with one ear not working well) and
> later, 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 inherent difficulties. 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) hearing 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 the 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 caution.
>
> 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. 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
>>>
>>> _____________________________