sparrowhawk dilemma (1 Viewer)

For the last couple of years i've had sunflower feeders and ut feeders hanging on a tree outside my office window attracting mainly finches and tits.
Occasionally and this has been very rare i've found small piles of plucked feathers indicating a possible sparrowhawk attack.
Anyway things have taken a turn for the worse,6 weeks ago we noticed a sparrowhawk sitting in the tree,male judging by the size of it.
Last week,carnage, a sparrowhawk flew straight into the feeding area scattering all and sundry,a greenfinch flew into our window trying to escape and was followed by the sparrowhawk who took it away.The sparrowhawk re-appeared an hour later and hasn't been seen since until..................
Yesterday afternoon i was walking to the fire escape door to re-fill the sunflower feeder when out of the corner of my eye i saw something hit the ground like a dart..yep,sparrowhawk was back and attached to him was another greenfinch.It all happened so quickly and he was gone withing 30 seconds.I would never have known he was there if it weren't for the fact that i was walking to the door.
My questions if anybody has any advice are
1):- Am i doing the right thing by continuing to feed or should i scale down the feeding for a while ??
2):- In view of the fact that it was only by chance i saw the attack,is it possible that this has been going unnoticed for the past couple of weeks ??
3):- How many small birds does a sparrowhawk require a day and are they territorial ??

Incidentally my mum and dad have video footage of a sparrowhawk attacking and killing a wood pigeon a couple of weeks ago.This bird was considerably bigger than the one outside my office and i'm amazed by the difference in size between the males and females.

finchy said:

My questions if anybody has any advice are
1):- Am i doing the right thing by continuing to feed or should i scale down the feeding for a while ??
2):- In view of the fact that it was only by chance i saw the attack,is it possible that this has been going unnoticed for the past couple of weeks ??
3):- How many small birds does a sparrowhawk require a day and are they territorial ??

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Hi Finchy,

Apologies for this standard reply but it has some useful tips:

It is an interesting point that many people try to change the conditions when they see predation occurring around feeding stations. I once took a call from a lady who stated that she had ceased feeding at high level because of sparrowhawks. However, this may not have been the best idea because that removes some sets of eyes and makes it unlikely that birds would detect an approaching hawk in enough time. Predators are a natural fact of life and the best idea is to give the smaller birds the best possible chance of detecting an approach. A string of old CDs or half-filled plastic drinks bottles are a useful visual distraction to control the success rate of the hawk. No deterrent has a 100% guarantee but it is sometimes possible to lower the success rate enough to move the predator away. Sparrowhawks (particularly, juveniles) can be confiding or at least, tolerant of humans especially in late summer when they are moving out to new territories. The key is to have the CDs in a prominent position but not so high that the hawk can see them before it reaches the garden. Hawks must lock-on to individual birds to make a kill and the CDs draw the eye at a vital moment. Unfortunately, it would be too much to expect 100% success because some small birds will always miss the warnings but it should reduce the rate of success.

Ian

Hi, I had a considerable amount of sparrow hawk kills - beautiful woodpeckers, pigeons,blackbirds singing one minute, dead the next! everything it could get... had the bird hanger above the kitchen window where we could see the birds and enjoy them.The sparrowhawk was not much worried by our presence.
In the end, I couldnt bear the carnage anymore. I got a ladder and put the bird hangers right inside the middle of a mature cypress (I think) tree. The sparrowhawk still tried its luck, once it shot into the tree and a wood pigeon shot out the other side...but apart from that one time the birds have been OK and it gives them the time to escape if necessary. Only drawbacks are you can't enjoy watching the birds feeding anymore, and I have to get the ladder to re-fill the feeders...

I wouldn't stop feeding personally, the Sparrowhawk is just taking advantage of a concentration of birds around an unnatural food source.

not nice to find they're being picked off, even if you wern't feeding they would still be taking small birds, just wouldn't see signs of it happening so much.

not sure about them being territorial but would imagine they are.

ended up moving my feeders so the Sparrowhawk didn't have the element of surprise on its side which seems to have worked, the birds have cover to dive into and alarm calls nearby scatter them before it gets too close.

still find bodies and patches of plucked feathers on a regular basis, I do like having them around though

finchy said:

.
My questions if anybody has any advice are
1):- Am i doing the right thing by continuing to feed or should i scale down the feeding for a while ??
2):- In view of the fact that it was only by chance i saw the attack,is it possible that this has been going unnoticed for the past couple of weeks ??
3):- How many small birds does a sparrowhawk require a day and are they territorial ??

Incidentally my mum and dad have video footage of a sparrowhawk attacking and killing a wood pigeon a couple of weeks ago.This bird was considerably bigger than the one outside my office and i'm amazed by the difference in size between the males and females.

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Hi finchy Im afraid you will have to live with you Sparrowhawk attacks even if you where to stop the feeding the Hawk is probably resident . Also the idea of using cd,s to put off the hawk attacks is also a no go as this has been tried by many people involved in my other hobby and found along with many other methods to be a complete waste of time .Sparrowhawk numbers are back above pre DDT levels and according to the BTO account for 107 million sparrow sized birds per annum and as a very successful predator they will continue to increase in numbers . The Sparrowhawk is a beautifull bird but in my opinion is at saturation levels , I think you will find more and more reports of Sparrowhawk predation on this forum some may think this is a good thing Im afraid I dont .

finchy, sorry about your problem - it is distressing and hopefully some of the steps suggested by others might help but bear in mind that according to all available evidence (not to mention simple logic) specialist predator numbers are controlled by levels of prey and not the other way round. The fact your garden is attracting a sparrowhawk is an indication that you have a healthy population of small birds.
best wishes,
James

You will probably be seeing more attacks from the male in your garden because the female will either be on eggs or very small chicks. The male has to do all the hunting and if the easiest place to do this where there is a great concentration of small birds are i.e. your garden, then this will continue. However, the attacks your drop eventually when the female starts looking for bigger prey when the chicks can be left alone in the nest and when the chicks are able to hunt for themselves they will be looking for their own territories. In doing this alot of them are killed themselves which keeps a territorial balance so there will not be more Sparrowhawks in your area but the hunting is greater at this time of year. I would say feed the birds, sit it out and let nature take it's course.

Gary.

have the same problem myself my feeders atract many small birds which in turn atract sparrowhawks but i suppose it is just nature greenfinches seem to be taken often here

While Stocks Last!

James Lowther said:

finchy, sorry about your problem - it is distressing and hopefully some of the steps suggested by others might help but bear in mind that according to all available evidence (not to mention simple logic) specialist predator numbers are controlled by levels of prey and not the other way round. The fact your garden is attracting a sparrowhawk is an indication that you have a healthy population of small birds.
best wishes,
James

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James,

Your theory that prey levels control predator numbers falls flat when applied to sparrowhawks. It also flies in the face of simple logic rather than confirming it.

At the Standing Conferance On Countryside Sports held in London recently, an RSPB representative confirmed that the UK population of sparrowhawks has now risen to 40,200 breeding pairs, with around a further 40,000 unpaired adults and juveniles, making a grand total of around 120,000 individuals. This is some 20% higher than the population estimate we have been led to believe was accurate in recent years.

In contrast, however, the population of many popular garden birds is still decreasing and has been doing so for a number of years. Why is this, if the predator/prey theory worked, then surely both would either be increasing or decreasing in tandem and not going in opposite directions? In my opinion, the only way this theory can possibly work is when the songbirds have all gone and the hawks are reduced to eating each other. By then it will be too late!

To claim that a garden which is attracting the attentions of a sparrowhawk
has a healthy population of small birds is also a short-sighted fallacy. Very quickly it will become a case of a garden without any small birds and a sparrowhawk which has moved elsewhere to resume the carnage WHILE STOCKS LAST!

Anthony

A Sparrowhawk in the area is in my opinion a good thing, it shows that there is a healthy bird population, if there wasn't an excess of small birds in the area you wouldn't get the hawk. But if you have cover for the birds nearby then move the feeders to give the small birds some protection.

Jackie

In my opinion, the only way this theory can possibly work is when the songbirds have all gone and the hawks are reduced to eating each other. By then it will be too late!

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:h?: is there an example in nature where that has been shown to happen?

Very quickly it will become a case of a garden without any small birds and a sparrowhawk which has moved elsewhere to resume the carnage WHILE STOCKS LAST!

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can only speak from my experience here, the garden where I've worked for last 13yrs has a very healthy population of small birds, and Sparrowhawks, as well as many other predators, Owls, Kestrels, Weasel, Stoat, Fox etc etc.

feeding attracts birds, that concentration of birds attracts predators, the only way to prevent it is to stop feeding but that's not saving them, the Sparrowhawk will still be killing small birds, just not on your doorstep.

Richard W said:

:h?: is there an example in nature where that has been shown to happen?

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Hi Richard,

The answer is 'yes' - if I understand your question correctly and we are discussing the ill-conceived theory that prey numbers will somehow control predator numbers, rather than the other way round!

I have been personally involved in the management of a lake as a coarse fishery for about 40 years. In the mid 60's it was producing good catches of roach, rudd, perch, tench, carp and pike. Fishing competitions were held on a weekly basis throughout the season and the weight of all catches recorded. By the early 1980's it was clear from the records kept that catches by both weight, number and species had declined alarmingly and that we had a problem.

An estimated 15 million gallons of water was pumped out, reducing the lake area considerably to facilitate netting. This revealed that almost all the roach, rudd and perch (the 'prey' species) had gone, leaving a small number of larger tench and carp. Surprisingly there was no evidence of any small tench or carp either. The reason for the decline was all too obvious from the exceptionally high number of pike (the predator) netted, which numbered in their hundreds. Our fisheries consultant predicted that if the drain-down had been left for another one or two years at most, there would have been NO prey species left at all. And since pike are known cannibals, in his opinion they were probably already reduced to predating their own kind at a much higher level than usual.

Sadly we were unable to establish exactly what had caused the explosion in pike numbers in this one lake, other than to say it was clear from the number of similar-sized fish that they must have had one or possibly two seasons when their spawning success rate was phenomenal. Don't forget also that this took place before cormorants and mink began to have any influence on fish stocks, so there were no other outside influences we are aware of.

In my opinion, a parrallel exists between what happened in this lake and the possible effect that sparrowhawks could have if their numbers continue to rise unchecked, while at the same time songbird numbers are allowed to decline even further. As I said in my earlier posting, sparrowhawk numbers are up and still rising, while songbird numbers are down and still declining. No one has contradicted this!

Regards,

Anthony

interesting but not sure the comparison between Sparrowhawks and a managed fishing lake really works...

I can't see it getting to the point where the skies are full of Sparrowhawks and not much else, makes no sense to me.

Richard W said:

interesting but not sure the comparison between Sparrowhawks and a managed fishing lake really works...

I can't see it getting to the point where the skies are full of Sparrowhawks and not much else, makes no sense to me.

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Hi Richard,

Then please read my post again. What I have outlined is a factual example of the damage an increasing population of predators can have on a reducing number of prey items if it is allowed to go unchecked. And it doesn't matter whether we are talking about sparrowhawks and songbirds, or pike and roach/rudd/perch, the effect is exactly the same. This is because the ever-decreasing number of prey items is simply unable to replenish itself at a rate equal to, let alone faster than, the rate it is being predated upon. In other words, the demands made by the predator is unsustainable and, if left to go unchecked, the prey species will eventually reduce to nothing.

Don't forget that the lake example I gave is based totally on recorded facts which were collated over many years. It also serves to illustrate that the theory which suggests that prey numbers are controlled by the availability of prey simply does not work in practice. That is unless you can give us an example of where it has happened, of course.

Regards,

Anthony

And it doesn't matter whether we are talking about sparrowhawks and songbirds, or pike and roach/rudd/perch, the effect is exactly the same.

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if that's the case then why did it not happen pre the Sparrowhawk population crash in the 50's & 60's?

Then please read my post again.

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I could, but it's not going to change anything, the two are not a good comparison afaic, and there's plenty of material out there which makes a lot more sense to me...

http://www.rspb.org.uk/birds/guide/s/sparrowhawk/sparrowhawk_-_a_top_predator.asp

in my opinion the problem is down to the increasing popularity of feeding birds, that has led to more people seeing Sparrowhawks in their gardens and no one likes seeing "their" birds taken.

will just have to agree to disagree.

Had a Sparrow-Hawk pop in for breakfast this morning.
Left with a Blue Tit.

That's nature.

Regards

Malky

Anthony you are happy for people to come and pay to catch your fish,doesn't this affect the balance? The Sparrowhawk is only doing what it is designed to do, unlike in your artificial environment. Open your eyes to the real world and don't talk a load of garbage! Tim.

Hi Richard,

Richard W said:

if that's the case then why did it not happen pre the Sparrowhawk population crash in the 50's & 60's?

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That's because until then the numbers of ALL predators, including the sparrowhawk, were controlled and had been for many years previously. By comparison there was no shortage of songbirds then.

I could, but it's not going to change anything, the two are not a good comparison afaic, and there's plenty of material out there which makes a lot more sense to me...

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The last two lines of paragraph 2 of your link repeat the theory (and that's all it is!) that predator numbers somehow rise and fall in direct relationship to their prey populations. Is that more or less a correct summary? If so, how do you explain that the UK population of sparrowhawks is now at its highest-ever recorded level (even higher than pre-DDT) and is still increasing, yet the population of so many of our songbirds has fallen and is still falling? If your theory held water, then surely the two should rise and fall in tandem, not going in opposite directions.

You also asked me for an example in nature which supports my opinion that, if given the opportunity, predators not only can but will reduce their prey species to nothing. In reply I gave you a factual, first-hand account of what happened to the fish in a lake which had not previously been managed in any way but had been allowed to develop on its own without any outside help/interference whatsoever. The eventual result was a lake full of predators and devoid of the prey species they required - exactly the opposite of the theory under discussion.

If you cannot accept that this is potentially a direct comparison with the current situation with the UK's birds, I'm afraid I can do little else to make it any clearer for you. I note that you have also failed to respond to my earlier request for an account of any situation which illustrates that the interaction between predator and prey numbers has ever worked in the way you believe it should if your theory is correct.

in my opinion the problem is down to the increasing popularity of feeding birds, that has led to more people seeing Sparrowhawks in their gardens and no one likes seeing "their" birds taken.

will just have to agree to disagree.

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I can agree with you here, at least in principle, but it's very much a double-edged sword when well-meaning people are being actively encouraged to spend large sums of money to attract birds into their gardens, only to see them slaughtered by predators!

Anthony

TWM said:

Anthony you are happy for people to come and pay to catch your fish,doesn't this affect the balance? The Sparrowhawk is only doing what it is designed to do, unlike in your artificial environment. Open your eyes to the real world and don't talk a load of garbage! Tim.

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Hi Tim,

I'm afraid your initial comment is based on a number of incorrect assumptions. For a start, people do not pay to come and catch 'my' fish, because I neither own or have any financial interest in the lake whatsoever. What's more, I certainly don't own the fish in it either. However, I have been a member of the angling club which holds the fishing rights for over 40 years. You must also understand that any fish caught are always returned to the water alive, so our members have no affect on the balance of either species or numbers.

What you have also failed to understand, is that far from being an artificial environment as you try to suggest, the lake had never been subjected to any outside influencies and had been allowed to develop in a completely natural way. This was particularly true for both the species and population of fish it contained. Indeed this was the first time that the lake had ever been drained and netted and accounts for why we were not expecting the huge number of predators (pike) it contained to almost the total exclusion of the species they prey upon.

As for your final comment, let's have a meaningful debate about this by all means but chucking ill-informed insults is not on. After all, how can I expect to get away with calling you a prat if I've never met you, or even spoken to you? I think the popular BF phrase is 'Play the post, not the poster'!

Anthony

Anthony Morton said:

James,

Your theory that prey levels control predator numbers falls flat when applied to sparrowhawks. It also flies in the face of simple logic rather than confirming it.

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Anthony,
it's not 'my' theory, it's the theory of pretty much every single ecologist/population biologist in the world.
The reason sparrowhawk numbers are increasing while population levels of some garden birds are falling is because there is still enough prey to sustain a larger sparrowhawk population (sparrowhawk numbers having started from an extremely depressed level thanks to the interference of our species). Eventually, when sparrowhawk levels have truly 'reached saturation', the increase will stop. Because populations of some prey species are in decline, that moment will inevitably come sooner than it would otherwise have done. I might remind you that there is no currency whatsoever amongst people who actually study and understand these things in the idea that sparrowhawks are the cause of any of the declines described.
As for the lake example, a sudden natural increase in pike numbers may have a catastrophic effect on the fish population in an isolated lake (although the fact that pike, unlike sparrowhawks, are cannibalistic, is significant), but this is no more a realistic model for the ecosystem of an entire country (in fact given the migratory/dispesive nature of many birds, the ecosystem in question crosses borders), than a fox being let loose in a chicken coop.
James