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Hi Donna, John & All, Aug 4, 2014
This question of 'ecological corrections' opens up a can of worms =
that, as Dr. Suess might have said, is so wide and so long and so deep =
and so tall, I can't talk about it , I can't talk at all.
But the subject of predation of bird eggs or young leads to a =
question about Swifts. Presumably the typical strategy of Swift nesting, =
large hollow trees, followed by chimneys and (most recently) the =
uppermost dark parts of unused barns reflects predation avoidance (high =
and/or dark being perceived as more safe than low and/or exposed to =
light). And even that abandoned dug well was likely dark and high in a =
negative sense.
Has any attempt been made to test Swift artificial nesting chambers =
of minimalist design ? Successful nesting in the upper reaches of a =
barn, where it would get very hot on a sunny day (I have been there =
stowing hay), and cold on a windy night with rain, suggests that the =
temperature stability provided by chimneys and large trees is not =
critical. Perhaps all they need is a rough plank structure that, from =
suitable cues, they can recognize as being safe enough from predators to =
use.
It could take two decades to come up with a practicable and =
affordable chamber design so this should not be left until the last =
minute.=20
If natural nesting sites are sufficiently abundant then why are =
Swifts nesting in barns ? Is the number of suitable barns expect to =
increase or decrease with time ?
Yt, Dave Webster, Kentville
----- Original Message -----=20
From: Donna Crossland=20
To: naturens@chebucto.ns.ca=20
Sent: Monday, August 04, 2014 6:41 PM
Subject: RE: [NatureNS] Fwd: Grey squirrel
A solid question to forward to the group, Richard.
=20
It triggers several thoughts from me. My husband carries out =
=E2=80=98ecological corrections=E2=80=99 here on occasion, in hopes of =
tipping the odds slightly more in favor of nesting forest birds, as well =
as swallow spp, etc. You will already be aware of some of the thoughts =
I write here, but thanks for the opportunity to reiterate some of my =
concerns as they relate to the decline of some bird species. =20
=20
Squirrels, raccoons, ... their numbers are elevated from human =
activities, from forest fragmentation to human-provided food sources. =
We use a variety of means to avoid enhancing populations of squirrels, =
blue jays, raccoons, etc. (We have many neighbours who still throw all =
food refuse behind their out-buildings. This activity mixed with =
farming activities have caused some populations to thrive while =
impacting other species.) The Nature of Things produced a documentary =
several years ago (perhaps most remember it better than I), and pointed =
to the elevated populations of raccoons, squirrels and blue jays, etc, =
contributing to the decline of some song birds. Both species of =
squirrels can and do consume eggs and young of nesting birds. The blue =
jay is probably an unusual prey item for the grey squirrel, but the =
jay=E2=80=99s bold behaviour around feeders likely makes them vulnerable =
to this new predator(?).
=20
With regards to grey squirrels, I=E2=80=99ve found them released in =
both Kouchibouguac and Kejimkujik National Parks, far away from the =
nearest populations of grey squirrels. The source is most likely from =
folks live-trapping them in backyards, then releasing them in =
=E2=80=9Cnice homes=E2=80=9D in national parks, where they can establish =
and create an added stressor to forest ecosystems. This sparks concerns =
on several levels.
=20
On a similar note, I have long been concerned with folks feeding =
squirrels, particularly in campgrounds, surrounded by =
=E2=80=98natural=E2=80=99 forest ecosystems (a dwindling resource). =
Many campgrounds have elevated squirrel populations. During springtime, =
prior to the arrival of high numbers of campers, hungry squirrels and =
raccoons must feed on something. Eggs and young birds pay the price for =
well-intentioned, but harmful human impacts caused by feeding peanuts to =
squirrels, marshmallows to raccoons, etc. It is challenging to find =
ways to urge folks to choose other ways to cure the nature deficit =
disorder. These actions are sometimes followed by complaints of chewed =
tent screens and severed wires to important vehicle lights, committed by =
the same mammals that they had been feeding during the weekend camping =
excursion. =20
=20
It may be considered futile (or wrong by some) to carry out backyard =
=E2=80=98ecological corrections=E2=80=99, particularly without objective =
research to justify the outcomes. However, I believe that such =
initiatives may have decreased nest predation in our woodlot, and may =
have assisted in the success of our nesting saw-whets (produced four =
fledglings) last spring. =20
=20
Donna Crossland (We are flying squirrel friendly folks!)
=20
From: naturens-owner@chebucto.ns.ca =
[mailto:naturens-owner@chebucto.ns.ca] On Behalf Of Richard Stern
Sent: August-04-14 9:21 AM
To: NatureNS
Subject: [NatureNS] Fwd: Grey squirrel
=20
Any thoughts?=20
Richard Stern=20
Sternrichard@gmail.com
Sent from my Android device=20
---------- Forwarded message ----------
From: "Mander" <mmander@ns.sympatico.ca>
Date: Aug 4, 2014 9:06 AM
Subject: Grey squirrel
To: "Richard Stern" <sternrichard@gmail.com>
Cc:=20
Richard
I thought I was seeing things, so I thought I would check with you. I =
heard a blue jay squawking then saw a grey squirrel carrying it up a =
tree. I could not get my camera in time to take a picture.
Mark
Sent from my iPad
No virus found in this message.
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08/04/14
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