[NatureNS] owl decline linked to forest decline

From: Donna Crossland <dcrossland@eastlink.ca>
To: naturens@chebucto.ns.ca
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Date: Sat, 06 May 2017 18:52:47 -0300
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Thanks to those who shared results of their owl surveys.  


Susann Myer's theory of barred owls not calling before "breakfast" is
interesting.  I've wondered at times, especially when evenings are very
cool, whether they just focus on getting a meal rather than checking out the
'new owls' being played at roadside.  My route in Kouchibouguac National
Park seemed to always have more owls toward the end of the survey than at
the beginning, though habitat remained about the same.  Maybe they joined in
after filling their bellies.  Priorities.


Considering that small mammal populations sharply drop off in clearcuts, it
seems very reasonable to assume that clearcut landscapes would support much
lower numbers of owls, if any.  And this ignores the barred owl's need for a
hollow tree of roughly 12 " diameter (if I recall correctly).  (I'm aware
that barred owls can attempt nesting on the ground when suitable nest trees
are not available, but I would question success rates with that option.)


My route is in Keji, where habitat has been constant.  I'll let you know my
results when I squeeze in a survey this week around the sprinkles and
drizzles.  I should have more consistent numbers (though realizing that
there are other variables like naturally fluctuating prey numbers, harsh
winters, etc, that cause rise/declines).  I've not done the Keji survey for
the past several years, so I may have to go to BSC in order to compare
numbers from previous years.  


It would seem that if we obtain consistently low numbers of barred owls in
the clearcut landscapes compared to intact landscapes, then the owl census
data may support what we pretty much already deduce using some common sense:
barred owls and other owl species are forest dwellers and cannot thrive in
the current harvest regime that has overtaken this province.   


In my opinion, it's time to start using years of bird data for something
extremely useful:  habitat protection, enhancing awareness of forest harvest
impacts on a range of bird species, demanding a silent period for harvesting
during nesting periods, etc.   


Donna Crossland 


From: naturens-owner@chebucto.ns.ca [mailto:naturens-owner@chebucto.ns.ca]
On Behalf Of James Hirtle
Sent: May-05-17 10:35 PM
To: naturens@chebucto.ns.ca
Subject: Re: [NatureNS] NOS - a great night for ambiance


The three routes that I run have definitely seen habitat removal and
destruction since I started them.  Many of the stops when you drive through
during the day show miles of clearcut the other side of a roadside tree
border.  Also, many houses have been built right where my stops are since I
started.  There are also stops where trees had been where owls nested and
they've removed these trees with selective cutting leaving no nest sites
behind.  It definitely has had an impact in those areas dropping them from
three species of owls to one or two species and finally to none for the past
two or three years.  It is sad to see this.  


James R. Hirtle




From: naturens-owner@chebucto.ns.ca <naturens-owner@chebucto.ns.ca> on
behalf of Richard Stern <sternrichard@gmail.com>
Sent: May 5, 2017 11:26 PM
To: NatureNS
Subject: Re: [NatureNS] NOS - a great night for ambiance 


I have run my owl survey for many years now - nearly always with Bernard
Forsythe - who probably knows more about owls than anyone else in the
Province, and more recently with Rick Whitman as well - an excellent set of
ears. I nearly always do it in late April, and on a night with light winds -
so reasonably comparable conditions.. There has been a steady and
progressive decline in the number and variety of owls, which I rightly or
wrongly ascribe to the increasing amount of clear cutting and logging going
on there (the South mountain above and behind Falmouth). At a recent BNS
meeting Bob Bancroft showed an alarming slide of a stylized aerial view of
the increasing amount of clear cuts in that area over the last few years.
This is not a scientific study, but an n=1 personal observation, but I
suspect there's a connection, as there are progressively fewer places in
that area for owls to roost and nest. 


On Fri, May 5, 2017 at 5:03 PM, Susann Myers <myerss@eastlink.ca> wrote:

Like you, Randy, I ran my owl survey last night - my route is at Earltown.
This runs through great habitat, and surveyors have often had counts of over
20 owls in past years.


Despite the bright half moon and light winds at the start of the survey, I
wasn't expecting great results on this survey, because winds had been strong
through the day, only becoming light in this location in late evening.  In
my experience, the owls don't sit up to do territorial calling unless
they've first had successful hunting in the afternoon and evening, and they
didn't get that in yesterday's winds.


The results bore out this idea.  I had only one very brief call from a
Barred Owl in the first seven stops.  Then after 11:00 p.m., when winds had
been light for about 3 hours, I began to hear owls.  I had five Great Horned
Owls calling in the last 3 stops, two pairs and a single, all giving quiet
contact calls. Also, one Barred Owl flew in after the second Barred
playback, giving Who-cooks-for-you calls.  After 7 quiet stops, it was
wonderful to hear owls.


Unfortunately, we can't wait for an ideal night.  With a week of rain
forecast, I needed to get my survey done while I could.  I don't like to do
a survey on a less-than-perfect night, because I don't think that the level
of analysis given to survey results is adequate to identify and adjust for
issues such as afternoon wind speeds.  Without that level of analysis,
however, how meaningful is the data in monitoring population trends?


Like Randy, I had an enjoyable night apart from owl results.  A fox crossed
the road at dusk, I saw Snowshoe Hare and deer, Woodcock were peenting at a
few stops and one was sitting in the road, and I had one snipe winnowing, as
well as a Ruffed Grouse drumming in bright moonlight at the final stop.
Pretty idyllic.  


Human disturbance was a factor, this year.  The road, which is not plowed in
winter, had some condition issues, including a washout on a sharp corner
above a very steep drop into a ravine.  A couple of residents who know me
from past years took on the (unnecessary) responsibility of protecting me
from this hazard, and wound up making a great deal of noise and disturbance
at two stops.  Hard to complain about such caring behavior, though!  Also,
in its own way, pretty idyllic.



Susann Myers


From: Randy Lauff <mailto:randy.lauff@gmail.com>  

Sent: Friday, May 05, 2017 9:21 AM

To: NatureNS <mailto:naturens@chebucto.ns.ca>  

Subject: [NatureNS] NOS - a great night for ambiance


Last night I ran my Nocturnal Owl Survey
(http://www.birdscanada.org/volunteer/atowls/) under i