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to tell this group that science is based on fact with thos --001a11427114c0e63b052a1f1a1a Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable folks, I agree that anecdotes will not get us very far on this one, since most of the impacts from cats go unwitnessed by us day to day. For anyone interested in seeing the research these national estimates are based on, it's open source and can be found here: http://www.ace-eco.org/issues/view.php?sf=3D4 (or by using the search terms= : 'quantifying human related mortality of birds in Canada'). The paper on *Felis catus* is here*: *http://www.ace-eco.org/vol8/iss2/art3= / (or use this search term: 'Estimated Number of Birds Killed by House Cats (Felis catus) in Canada') True, forest loss and fragmentation, and climate change are not included in these comparisons, but despite that, it is good to know what '196 million birds' (estimated annual mortality from owned + feral cats) actually looks like to see if it is worth our time. If we don't really have a good sense of what '196 million birds' is, or, think that it is a negligible amount then it's easy to pass off. Take a look at some population estimates for our Canadian birds here in the Partners in Flight Population Estimates database: http://rmbo.org/pifpopestimates/Database.aspx (Canada column). Details on methods of deriving these estimates can be found here: http://rmbo.org/pifpopestimates/About.aspx. For context, here's how 196 million annual mortalities lines up to PIF Canadian population estimates for various species (clearly, some species would be more vulnerable than others): PIF Canadian population estimates for some NS species of concern... Tree Swallow - 7.6 (M)illion Barn Swallow - 5 M Chimney Swift - 0.08 M Common Nighthawk - 0.9 M PIF Canadian population estimates for some species nesting near the ground in my neighbourhood: American Robin - 140 M Black-capped Chickadee - 20 M Chestnut-sided Warbler - 13 M Gray Catbird - 3.6 M Great-crested Flycatcher - 0.59 M Northern Cardinal - 0.5 M (now we're at 191 M...) ... As the authors of the above paper point out, this is also just the tip of the cat-impact iceberg: *"Because most bird species in Canada are migratory, including most species that are potentially vulnerable to cat predation, many birds will be subject to additional cat predation after they leave Canada, particularly as they migrate through and/or winter in the U.S., where numbers of pet cats and especially feral cats are much higher. Thus the proportion of Canada=E2=80=99s birds killed by cats will b= e higher than estimated above using predation rates in Canada alone."* james On Sun, Jan 24, 2016 at 4:01 PM, John and Nhung <nhungjohn@eastlink.ca> wrote: > I agree that predation is an important selection pressure, but if various > pressures on a population are so high that the population doesn=E2=80=99t= have 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 > attempt to stand back and identify the major forces before fussing about > possible 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 quali= ty > and habitat continuity. Abundant food in July is worthless if May, June, > August and September are filled with want. > > > > Predation usually has the effect, on average, of removing the less > agile, the less healthy and less the capable and thereby gives the > remaining population better access to food, shelter etc and a better shot > at survival. For a stable population, temporary growth must be balanced b= y > attrition. So predation can have an effect on population only in extremel= y > unusual circumstances [ e.g. flightless birds who evolved in the absence = of > flightless predators, 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 > somehow nab them just before or just after landing ? > > > > Yt, DW, Kentville > > ----- Original Message ----- > > *From:* Nicholas Hill <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 reducing 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 lo= ok > at tempering the minor threats which we are not going to fully eliminate = as > they 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 wa= s > 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-wi= ndow-collision-animals-science/ > > > > We won't get anywhere legislating that cats be not allowed out but > increasing attention on barn populations and making people responsible (o= r > finding funding for) for fixing barn cats on their property, then > suggesting that owners keep their cats in at dusk and night, will have > impacts. Currently, this negative focus on cats creates the impression th= at > a biodiversity crisis is the fault of cats not their humans who may also > drive cars profligately 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 > irresponsible owners are exactly that. Myself, living in