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the " Declines in
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I agree that predation is an important selection pressure, but if various p=
ressures on a population are so high that the population doesn=E2=80=99t ha=
ve time to respond, aren=E2=80=99t we looking at extirpation or extinction?=
From: naturens-owner@chebucto.ns.ca [mailto:naturens-owner@chebucto.ns.ca] =
On Behalf Of David & Alison Webster
Sent: January 24, 2016 3:33 PM
To: naturens@chebucto.ns.ca
Subject: Re: [NatureNS] Vancouver has new "bird strategy"
Hi Nick & All, Jan 24, 2016
Once again I think your overall approach is sound. One should always at=
tempt to stand back and identify the major forces before fussing about poss=
ible minor forces.
And if the context is species decline then it will be strange indeed if=
the three major forces at play are not habitat quantity, habitat quality a=
nd habitat continuity. Abundant food in July is worthless if May, June, Aug=
ust and September are filled with want.
Predation usually has the effect, on average, of removing the less agil=
e, the less healthy and less the capable and thereby gives the remaining po=
pulation better access to food, shelter etc and a better shot at survival. =
For a stable population, temporary growth must be balanced by attrition. So=
predation can have an effect on population only in extremely unusual circu=
mstances [ e.g. flightless birds who evolved in the absence of flightless p=
redators, such as rats.].
Swifts, so I understand, land only after they have entered a nesting or=
communal roost. And I also understand their decline has been dramatic. How=
much of their decline is due to flying cats or other super-cats who someho=
w nab them just before or just after landing ?
Yt, DW, Kentville
----- Original Message -----
From: Nicholas Hill <mailto:fernhillns@gmail.com>
To: naturens@chebucto.ns.ca
Sent: Sunday, January 24, 2016 1:37 PM
Subject: Re: [NatureNS] Vancouver has new "bird strategy"
yes Darrell, they have an impact. My point is that this factor is overblown=
and is not put in context of the many other factors that are truly reducin=
g bird populations in the temperate region:
climate change
land use (e.g. short rotation forestry)
pesticides
oil?
Cats, cars, windturbines, reflective glass would be minor in comparison and=
I'd suggest we first focus on the major causes of decline and then look at=
tempering the minor threats which we are not going to fully eliminate as t=
hey are part of our life style:
1. Cat--keep cat in at night, fix feral cats and get them places
2. Car--slow down..I killed a swallow last year when in what I thought was =
a hurry
3. Windturbines--research placement of windmills out of flight pathways
4, Glass--hard to know how to reduce bird impacts on existing windows, this=
national geographic article discusses some ways
http://news.nationalgeographic.com/news/2014/11/141113-bird-safe-glass-win=
dow-collision-animals-science/
We won't get anywhere legislating that cats be not allowed out but increasi=
ng attention on barn populations and making people responsible (or finding =
funding for) for fixing barn cats on their property, then suggesting that o=
wners keep their cats in at dusk and night, will have impacts. Currently, t=
his negative focus on cats creates the impression that a biodiversity crisi=
s is the fault of cats not their humans who may also drive cars profligatel=
y and eat crops grown using neonicotinoids.
Nick
On Sun, Jan 24, 2016 at 11:43 AM, <darrell@abolitphotos.ca> wrote:
I disagree Nick, any animal can become a pest and cats and their irresponsi=
ble owners are exactly that. Myself, living in the countryside where cats a=
re brought to barns and dropped off and many owners letting them roam free,=
I have seen many birds killed. Seen one cat jump up on a cloths line to ki=
ll a saw-whet owl. An impressive predator but way too many (all) at loose i=
n the daytime and night. Dog owners are not allowed to let their animals/pr=
edators roam free and neither should cat owners. No pet should be allowed t=
o roam free to kill at will, period.
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
On Sun, 24 Jan 2016 11:24:43 -0400, Don MacNeill <donmacneill@bellaliant.ne=
t> wrote:
I agree Nick.
Don
Don MacNeill donmacneill@bellaliant.net
On 24/01/2016 10:37 AM, Nicholas Hill wrote:
Grayson and Calver (2004, Regulation of cat ownership to protect urban wild=
life: a justification based on the precautionary approach. Royal Zoological=
Society NSW 169-178) found previously that Cat Density was not a predicto=
r of passerine numbers but that distance to bushland and the density of urb=
an housing were (both negative factors). In the study cited above (regulat=
ion of cat ownership etc), they conclude that "cat welfare is the key issue=
in a precautionary approach for protection which respects interests of cat=
owners". Cat welfare means keeping the beasts in at night and desexing the=
m so that we do not have a feral cat problem. In the country here, people l=
et cats breed in outbuildings and this leads to a desperate situation for t=
hese cats and for wildlife.
Other authors warned that conclusions drawn in Britain over the impact of c=
ats (million birds and small mammals killed) were drawn from data on one si=
ngle village study in Felmersham. This author (BM Fitzgerald, 1990. is cat =
control needed to protect wildlife? Environmental Conservation 17: 168-169)=
questioned the extrapolation which we should in a rural area like NS where=
birdlife is spread widely over woodland and clearings
We have 3 desexed rescue cats that are in at night and well fed. There is a=
local impact on mouse, vole and shrew (no birds seen taken yet) but the po=
pulation of these animals is greatly increased by the landuse round the hou=
se..as was observed in Felmersham (rodents and house sparrows there).
Surely all of the following factors need to be considered before we relegat=
e the cat to the indoors:
woodland edges..plant more trees
brush piles..dont be tidy, a pile of woody debris is a refuge for small bir=
ds and voles
sustainable agriculture..minimize use of pesticide sprays (see the " Declin=
es in insectivorous birds associated w hi levels of neonicotinoid" in Natur=
e 511: 341-3 (2014) and http://news.nationalgeographic.com/news/2014/07/1=
40709-birds-insects-pesticides-insecticides-neonicotinoids-silent-spring/)
Cats connect people to nature, to animals that still have independence and =
aloofness and are not wholly removed from primary adaptations. This makes t=
hem attractive in connecting and grounding us but it also i