How many birds do cats really kill?

[Ragtime]

In the recent Birds Britannica show (week 1) the presenter said that cats are responsible for killing 50 million birds a year. I think I have remembered that correctly, yet even a casual flick through the RSPB guide totalling up the number of garden/woodland birds in Britain makes this almost impossible to believe.

Did I mishear? If not surely that number is incorrect? After all we have a dozen other reasons for birds dying as well to add to this number.

Any thoughts?

[eeyore]

Lots of other threads on this already - most closed amnd/or deleted because people started getting agrro with each other.

CATS: How do I get rid of them?

Raising baby birds.

if we must go there again, perhaps this time we can avoid a replay

[Ragtime]

Ooh no, I don't want any aggro
Just wondered if there really was a definitive (although estimated of course) number for bird deaths caused by cats because that programme's estimate of 50 million a year seemed almost unbelievable.

[RoyW]

Originally Posted by Ragtime

In the recent Birds Britannica show (week 1) the presenter said that cats are responsible for killing 50 million birds a year. I think I have remembered that correctly, yet even a casual flick through the RSPB guide totalling up the number of garden/woodland birds in Britain makes this almost impossible to believe.

Did I mishear? If not surely that number is incorrect? After all we have a dozen other reasons for birds dying as well to add to this number.

Any thoughts?

Without getting into the pros and cons of keeping cats, you may be surprised at the number of birds that do die each year (all reasons, not just cats).

Generally, for most passerines only 2 birds per pair are expected to survive until the next breeding season, so if we look at a few figures:

Blackbird: 4 million pairs, each producing two broods of three = 24 million that don't survive until the next year.
Blue Tit: 3 million pairs, each producing a brood of six = 18 million that die.
Chaffinch: 5 million pairs, each producing a brood of three = 15 million lost
Robin: 5 million pairs, each producing two broods of three = 15 million dead.

So, despite the fact that I have only looked at four common species (and I have deliberated reduced the estimated breeding population, the number per brood, and (to some extent) the number of broods, we are already at 72 Million! (and for these four species it's probably really nearly double that)
If I continued to total up the number of young produced by all of the UK's bird species that might be taken by cats, 50 million would end up as a fairly small percentage.

If you also look at the number of cats in UK ownership (estimated at 10 million, based on government figures), then for 50 million to be killed by cats they only have to take 5 birds a year on average - easily below a believable level, even if you take into account the fact that many will kill none.


So no, you probably didn't mis-hear. It is easily possible (and if there were no other threats to birds it would probably be easily sustainable - especially as the numbers of natural predators in many parts of Britain are still below natural levels because humans killed most of them).


Surveys have confirmed the figures of around 50 million birds killed, eg. this one (and even the cat protection league apparently give the same figure).

[captaincarot]

around 50 million per year being birds is actually around 10% of the total prey items that cats needlessly kill in Britain each year based on some conservative calculations.

obviously not all 500 million are birds, they kill small mammals, amphibians and reptiles too.

[rossy]

what you need to realise is that they kill garden birds for fun, and that alone is a big problem, espescially as some are declining at an alarming rate, rossy.

[The Woodman]

Is it "fun" or some genetically ingrained predatory killing response that's been partially repressed by breeding?

[bigdave60dog]

Don`t know how many they kill but it`s loads. When I first had my own garden I said "no cats" to my Kids as I like birds in the garden more than I like cats.
Before long every cat in the road was in my garden crapping and catching birds.
OK Kids have your kitten" i said. They got two. We put loud bells on collars so that they could not creep up on birds very well. they kept the other cats out of our garden and we had the pleasure of owning cats.
I can`t do this now as there are too many wild places with snags so the cats don`t keep collars on for long. I would recommend this in a suburban setting. Keeping cats out of your garden is like trying to trap wind under a blanket.

[Paul mabbott]

Originally Posted by rossy

what you need to realise is that they kill garden birds for fun, ........

Mmm..... I think it's not really correct to say they're doing it for fun. All/most young felids (and many other predatory species) learn how to hunt by game-like behaviour. Since domestic cats have been artificially selected (by humans) to stay kittenish, they retain much of their youthful behaviour - neoteny. So they're not catching birds etc for fun, as such, they just haven't grown up and are practicing for when they do.
It's noticeable that older cats are less likely to attack birds (maybe has something to do with arthritis and other ageing processes ) whereas cats which are left to fend for themselves will catch all sorts of things and eat them. The behaviour is not really different between these.

[Dogghound]

The real issue in my opinion is that the density of cats present in most areas is far greater than that of any natural predator. Due to cats being fed and sheltered by humans their number always remains high. Something which would never occur in a typical natural predator prey relationship, so the birds never get recovery its constant.