| Archive for Downsizer For an ethical approach to consumption |
| Cathryn |
Magpies and jaysAre we still overrun with them? Should they still be seen as vermin and a threat to our smaller bird species? |
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| tahir |
Jays are quite rare here, loads of magpies. | ||||
| tahir |
And we're still owned by the crows. |
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| Cathryn |
Well yes, I could have added crows . There doesn't seem to be that many jays here, hence I released one back into the woods this morning.
Seems all based on a bit of an emotional response, my own as well; my heart lifts when I see a flash of jay's wing in the woods. I wondered what everyone else thought and I wondered if there is any evidence on how much of a threat they actually are. |
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| Treacodactyl |
I think magpies must have been rarer in the past, the saying "one for sorry, two for joy etc" doesn't seem to go up to 20, which is the number I counted in a tree this year. There's always loads of magpies about here, less jays but they are very common. | ||||
| Silas |
Re: Magpies and jays
Its not the threat to smaller bird species that is considered the problem , its the threat to 'game' birds. |
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| Pilsbury |
I love catching a glimps of a Jay and as Tahir says relativly rare in these parts, i have only seen 4 or 5, but magpies are everywhere, I drove down canvey way to see my dad the other day and counted 23 pairs on the edge, the road is only a few miles long 
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| Cathryn |
Yes I wondered that. There isn't a shoot here now but there used to and the idea might still be there. They do take young birds however and there are low numbers of some of those. There are also a lot of magpies.
When I get chance I will see if I can find "facts and figures". This was in response to Silas. |
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| Treacodactyl |
I've not noticed jays do much harm, but they seem to stay more in the trees round here.
Magpies are everywhere and come right down to the house, rummage in bins etc and I've often seen them go after nesting wild birds we have in the garden. You also often see and hear other birds trying to chase them off. |
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| Silas |
Oh yes, they do take young birds and eggs, but although the magpie population has almost exploded over the past 7/8 years, it has had no significant effect on small bird numbers. |
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| Cathryn |
I wanted that answer Silas.  I need to find more evidence of some kind however. I, of course, would take you at your word. 
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| Gervase |
I read somewhere that the magpie is now the UK's seventh commonest bird. Quite why the population has exploded is a mystery - keepers can't have accounted for that many in the past.
They're mainly a pest for ground-nesting birds (incuding pheasants and partridges - hence the keepers' traditional antipathy), but as Silas says, they don't seem to have made a huge impact. Unless, that is, the magpies have conspired to wipe out the house sparrow and we haven't noticed... |
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| Penny Outskirts |
The gits sit and wait on the fence outside our house for the little house sparrows to fledge from their nest under our eaves 
I throw things at them 
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| 12Bore |
A chap on CountryFile just said that the Magpie population has doubled in the last 30 years or so! | ||||
| pookie |
we have several magpies and crows taking our eggs 
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| Green Rosie |
It's the other way round here - I see jays most days but magpies only rarely and never in large numbers. We have a very healthy population of small birds. I saw a yellowhammer last week for the first time in a very long time. |
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| Treacodactyl |
I can't actually find any independent research that says magpies don't reduce wild bird numbers. There's some comments on the RSPB site about looking at historic data and there's some research on the GCT site that seems to support the idea that predation does reduce numbers of birds.
Anyone know of any independent research? It would seem quite easy, take two similar areas where magpies are abundant, heavily control them in one area and see what impact that has on the wild birds. |
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| Bernie66 |
I have heard it implied on a recent "farming today" R4 podcast, I think it is too far back for you to be able to catch it on play again though | ||||
| Silas |
According to the RSPB magpie numbers are now at about the level they were before decimation by DDT etc. |
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| Treacodactyl |
Which has nothing to do with my question. 
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| Silas |
OK. You want to kill a load of magpies in one area just to see what happens? Is that really a good idea? How about killing all the cats in one area to see what happens? |
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| Treacodactyl |
So you don't know of any independent studies then?
Funny you should mention cats. What I don't understand is the fact we know animals like jays, cats and grey squirrels predate wild birds and other animals. Most people accept that and the advice is often try and provide places which will protect birds from predators. However, we then get told that the predation doesn't actually affect the populations, so why do we need to provide protection from predators? It does seem various people and organisations contradict themselves to some extent. |
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| Pilsbury |
sounds good although when were cats reclasified as vermin, must of missed that announcement.
just curious but if a restaurant has a zero star rating due to a mouse infestation as the owners had a thing about not killing or discuraging vermin would you still eat there? nothing to do with songbirds I know but just wondered if you were against the control of all vermin species or just corvids |
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| Silas |
I am not sure where you get this advice about providing places that will protect birds from predators, OK, you may wish your garden bird table to be cat proof, but that is about it. One birds offspring is another birds meal - that is the way of nature. |
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| Treacodactyl |
The advice is everywhere. The first place I looked is the BTCV and they state "Birds need cover to escape predators".
An example from the RSPB "Nestbox predators include cats, squirrels, rats, mice, stoats, weasels, woodpeckers and, in case of open fronted boxes, members of the crow family. As predators mainly hunt early in the morning, most people are unaware of their presence. A metal plate fixed around the entrance hole may deter woodpeckers and squirrels, while barbed wired, gorse or rose clippings above and below the box will give some protection against most mammals. Various commercially available deterrents may also help reduce predation. " It would be "the way of nature" if humans didn't affect nature, but we do by a huge amount. |
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| Cathryn |
I was wondering however if it is based on any facts. Jays, magpies, the creatures that take other birds eggs and nestlings have probably been labelled as vermin as they threatened game birds. All the farmers would have been involved in the shoots around here. Has this memory/habit continued for any other good reason? |
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| Mutton |
Last year my neighbour killed 8 magpies on the grounds they were eating all his hens eggs.
Then he discovered it was his own terrier dog eating the eggs. |
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| bibbster |
I definately know that Magpies eat my hens eggs, they can steal all of them, upto 6 every single day, if I make the mistake of leeting the hens out to range before they have laid. And if they can get in the henhouse they will too. This means I can only let my ladies out after about 1pm when those that are going to lay have done so. There are about 8 or 10 magpies around at present, presumably some are young one. If they are eating hens eggs, they are probably also eating other birds eggs?
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| Cathryn |
Oh they definitely eat birds eggs. A talented, intelligent, adaptable species. Why do we kill them is what I wanted to understand. | ||||
| robin wood |
This is largely an emotive issue and as has been said it would be fairly straightforward to conduct the research but who would fund it? Who would stand to gain by finding out that magpie does or does not have a limiting effect on a particular songbird population?
If you proved it in just one area would that prove that magpie predation is always a limiting factor or is it more likely that in one area predation is a limiting factor and in another nest sites and another food source. RSPB is a campaigning organisation scientific data comes from BTO. Here is their basic info on magpie population. 
Status summary The high level of adaptability displayed by Magpies has allowed them to colonise many new urban and suburban localities since the 1960s. Magpies increased steadily until the late 1980s, when abundance stabilised (Gregory & Marchant 1996). The trend has been associated with improvements in breeding performance, as has been observed for other corvids, and probably reflects the benefits of a generalist strategy under changing environmental conditions. The declines in nest failure rates, during both the egg stage (21 days, comprising 17 days incubation and 4 days laying) and the chick stage (25 days), have been substantial, and are likely to be the result of reductions in gamekeeping activity (Marchant et al. 1990). A strong trend towards earlier laying has also been identified and may be partially explained by recent climate change (Crick & Sparks 1999). source http://www.bto.org/birdtrends2003/wcrmagpi.htm Now if you have been watching the blackbirds feed their young in your garden for 3 weeks and then witness magpie raid the nest it is hard not to believe they are a limiting factor. Funny how we don't get as upset when woodpeckers raid nests, I think we dislike anything that is too successful, particularly generalists like magpies, rats, gray squirrel. Last time I asked a guy at the BTO there was no data suggesting magpie or other corvid predation as a limiting factor in songbird population, that was 10 years ago but that was well after the major increase in population which occurred between 1970 and 1990, it has been pretty stable for the last 20 years. The question I would like to ask is do you think you can successfully limit population of magpie? Or would popping a few off just make you feel better? What happened in 1990 to stop magpie increasing more? Seems to me that now the limiting factor on magpie is not how fast they can breed but food and nest site availability. When a population is in this state then killing a few or even a lot simply means they breed more to fill the gaps. The level of control required to seriously reduce the population is huge. Full time gamekeepers used to spend a great deal of time on predator control, popping a few off has little or no effect on the population. Just found this on BTO site However, Gooch et al. (1991) found no relationship between magpie density and songbird breeding success. Thomson et al. (1998) reported that patterns of songbird decline were similar both in areas where predators occur and in those from which they were absent, suggesting that increased rates of predation are unlikely to be responsible for the observed trends. http://www.bto.org/research/advice/birdsconconcern/bccsection511.htm |
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| Cathryn |
Thank you for that site, very interesting and made for an interesting discussion here at home.
(By the way, it's not us who traps these birds.) |
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| Treacodactyl |
When I had a quick look at a RSPB / BTO study it said it was based on data collected on sites where magpies exist and sites where they don't. I am a bit sceptical of that as for magpies to not exist somewhere in the lowlands of the UK I'd expect something else to be wrong in the area so I'm not sure how if you could draw conclusions from the data. IIRC it also said no study has been done in an urban environment.
I looked at the GCT studies and they seem more realistic. At a quick glance some suggest magpie control works, others don't which seems more balanced to me. But I know some people would just dismiss them. Round here, which is suburban, I think controlling what people do would have far more impact on magpie numbers than controling them. I get the impression more survive the winters due to the amount of food they can scavenge from rubbish. I can see how controling magpies would help in specific area where there's small, local, populations of rare birds. Don't some wildlife sanctuaries control them? I still think there isn't enough information to know one way or other and there's questions which the reports don't seem to answer. For example, it's accepted that magpies do take eggs and chicks but why does this not affect the numbers of adult birds. Edit to add: and I've just read that the increase in cars might be the main reason for the increase in magpies due to the increase in roadkill available during the winter. Another thing to blame motorists for. |
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| Cathryn |
There are so many variables. It struck me that I could do one of those garden watch type things and just count for an hour at different times of the day and month, the number of corvids that I see and get kind of useful numbers from that. | ||||
| Treacodactyl |
If you're thinking about controling them I'd start off by asking what are you protecting. So is there anything rare that they predate, which isn't just birds I've seen them take slowworms for example, or is there anything you particularly want to look after such as nesting game birds. Then I'd ask if there's anything more useful I could do such as provide shelter and protection for the prey. Then think if action on your own would do any good or if you can get others to join in etc. | ||||
| Cathryn |
I'm not - my neighbour does a little but what's happening now is that we are releasing the jay's which we were surprised to have caught in any case. (The trap is set for squirrels.)
I was really considering my uneven emotional response however. I am torn between admiring the opportunism of a carrion crow that has learnt to peck at any lamb if the ewe is struggling at all to give birth to it and disgust at seeing the result of this. I would like this bird dead in case it passes on it's new trick to any of the others. I also felt that there are a lot of magpies but not so many jays so made sure to release the jays (haven't actually caught any magpies in any case). All subjective reponses. |
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| robin wood |
Good question. The answer is it might and it might not depending on what is the limiting factor on the given population. Populations expand until they reach some limiting factor, that can be lack of nest sites, most commonly lack of food, or particularly in animals that mature late and breed slowly like gorillas or larger whales when mortality exceeds birth rate. I remember an interesting PhD on foxes which discovered that they limit their breeding when the population has low mortality. They often live in groups with several females and only the alpha female will breed, litter size also decreased with low mortality. In areas of higher mortality (eg urban environments with more road kills) all the females were breeding and litter sizes were larger. So artificially increasing mortality in the first circumstance had no effect on population size because mortality was not the limiting factor it simply encourages them to breed faster. The forestry commission (as was) did a huge amount of research on the effects of gray squirrel control and found that however successful they were 3 months after control ceased the population returned to previous levels (from memory). In practice this meant that it was not economically viable to maintain control and low population year round, instead they target control during the months that they damage trees resulting in a short term drop in population and resulting damage. I think it is important to note that the study I posted the link to is BTO not RSPB. "The British Trust for Ornithology has existed since 1933 as an independent, scientific research trust, investigating the populations, movements and ecology of wild birds in the British Isles." This remit is I suspect likely to produce more objective and reliable research than "The RSPB speaks out for birds and wildlife, tackling the problems that threaten our environment." or The Game Conservancy Trust charitable objects: "to promote for the public benefit the conservation and study of game species, their habitats and the other species associated with those habitats." |