How can we save the rooks.

General birdwatching discussion, help with bird identification, and all other things relating to wild birds and birding in NZ that don't fit in one of the other forums.
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Neil Fitzgerald
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Re: How can we save the rooks.

Postby Neil Fitzgerald » Sun Jun 03, 2018 12:03 pm

That's not an objective comparison.
I have personally never seen a ship rat prey on a bird nest, but the science tells us that is a major (if not the biggest) threat to many of our native birds. On the other hand, I have seen a magpie kill a blackbird, and a myna kill starling chicks, but the science tells us neither are significant predators of native birds, compared to the other threats they face. I have no reason to doubt any of this, until and if there is stronger evidence to the contrary.
I don't know where rooks fall in comparison to mynas and magpies, but there is a perception they are harmful to agriculture. The big difference is that managers seems to think they have a chance of eradication.
As previously mentioned, probably the only thing you can do is not publicize too much detail of sightings (especially nests).
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Re: How can we save the rooks.

Postby flossiepip » Sun Jun 03, 2018 1:42 pm

My knowledge and experience with this bird here in various parts of Northland tells me that they are a major pest to native and introduced birds, reptiles and insects too. There great numbers seem to overwhelm the local garden birds and their competition for nesting sites is very noticeable.
A quick look on web sites would seem to back this up with the Australians seeming to be almost pathological to the bird, I am sure that I read somewhere that they consider it to be the second biggest threat to native birds after land clearance! Indeed they refer to it as the-Flying Cane Toad and if you look further not only is it now seen as a major pest in many country's but is being blamed for bringing many native birds to the brink of extinction, I believe if memory serves me well that I read that Hawaii and Mauritius, two country's with a long history of man induced extinctions name this bird as one of their major concerns.
In the year 2000 the International Union for the Conservation of Nature the IUCN named the Common Myna in the 100 of the worlds most invasive species.
I believe that this information is still there to be googled.
Clinton9
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Re: How can we save the rooks.

Postby Clinton9 » Sun Jun 03, 2018 3:03 pm

Common mynas are not welcome in NZ, they are threat to our native birds, they are very aggressive birds and in mid 1990s in farmland, north of Hamilton I had watched a adult male Australian magpie chasing the juvenile myna. The juvenile myna screamed as it flew fast as the magpie were closing toward fast flying myna, other mynas were on ground, watching the the flying magpie chasing a myna, then they took off and went after magpie.
Then mynas mobbing the magpie, then magpie flew away, with angry mynas flying after the magpie, in a large flock.
Other mynas flew to trees and watching the large flock of mynas flying after a magpie.
During late 2000s near my place I saw a myna attacked a fledgling European starling on footpath, but an adult starling flew to beat up a myna, then myna flew away. At Brightsmile Community Garden during late 2000s I watched a pair of European blackbirds defending their nest from a myna, with a female blackbird attacked the myna, then myna flew away.
I had watched them fighting on roof and ground.
I am worried, as numbers of mynas increased, they are spreading southward as climate warm up, these mynas will kick these North Island kakas (dull brown forest parrot) and red-crowned kakarikis out of their nest holes in trees, and mynas may attack fantails by flying after them to catch them same way as mynas catching flying insects.
During 2000s when I started to work in farm and when nest boxes were installed along top of fences, European starlings used the new nest boxes for several years, then Common mynas came and kicked the starlings out of nest boxes and took over the nest boxes, then they bred.
Over last 18 years numbers of starlings in farm whose I working, decreased and disappeared, while mynas increased and now the farm have large flock of mynas, during wintertime and springtime.
During 2000s I have seen rooks few times when I were in Miranda, these birds were flying singly.
john b
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Re: How can we save the rooks.

Postby john b » Sun Jun 03, 2018 3:10 pm

As our knowledge increases we will have the ability to deal with a lot of introduced pests including avian ones. Personally I would be very happy to see the last of rooks magpies and mynas. One thing I have noticed is that the more intact the native ecosystem is the less exotic species you tend to see.
Jim_j
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Re: How can we save the rooks.

Postby Jim_j » Sun Jun 03, 2018 3:28 pm

Thanks for that link Clinton.
Does anyone know why Rooks were introduced?
If they eat seedlings etc surely they were doing the same thing in the UK & Europe?
You have to wonder if those early old blighty immigrants were blessed with much intelligence...!
As Neil et al have mentioned the small numbers that remain aren't likely to be much of a problem.

I would disagree Neil re Magpies/Myna & Rosella? - the science might show they don't have much impact on some natives - but it can't show the impacts on those species that aren't currently there.... so planned reintroduction say of birds like kakariki, falcon, kaka could well be impacted by high numbers of these birds

cheers
jim
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Re: How can we save the rooks.

Postby Clinton9 » Sun Jun 03, 2018 3:30 pm

To deal with rooks, Canada geese, mynas, is we would plant more trees (reforesting) and leave the grasses unmowed and long, or we would build huge plants / orchard / vegetable houses to keep birds out.

Or use our native falcons to keep mynas moving more often & control their numbers.

During 1776 NZ were largely forested, the Paradiae shelducks were confined to grasslands and lakes in southern South Island only.
Today the shelducks are widespread in NZ, thanks to humans cleared the forests and NZ had several native forests.
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Neil Fitzgerald
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Re: How can we save the rooks.

Postby Neil Fitzgerald » Sun Jun 03, 2018 4:09 pm

Jim_j wrote:I would disagree Neil re Magpies/Myna & Rosella? - the science might show they don't have much impact on some natives - but it can't show the impacts on those species that aren't currently there.... so planned reintroduction say of birds like kakariki, falcon, kaka could well be impacted by high numbers of these birds

cheers
jim

In fact, kakariki have successfully established in the presence of myna and rosella (e.g. Tawharanui), and at other places where mammalian predators have been eradicated (e.g. Little Barrier and Tiritiri Matangi) myna are now rare, apparently out competed by the endemic birds. Mynas, rosellas and magpies could easily recolonise these places, but now that the mammals are gone, something is keeping them out.
It seems the best way to deal with mynas (and many other introduced birds) is to get rid of introduced mammalian predators.
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Re: How can we save the rooks.

Postby Neil Fitzgerald » Sun Jun 03, 2018 4:41 pm

flossiepip wrote:My knowledge and experience with this bird here in various parts of Northland tells me that they are a major pest to native and introduced birds, reptiles and insects too. There great numbers seem to overwhelm the local garden birds and their competition for nesting sites is very noticeable.
A quick look on web sites would seem to back this up with the Australians seeming to be almost pathological to the bird, I am sure that I read somewhere that they consider it to be the second biggest threat to native birds after land clearance! Indeed they refer to it as the-Flying Cane Toad and if you look further not only is it now seen as a major pest in many country's but is being blamed for bringing many native birds to the brink of extinction, I believe if memory serves me well that I read that Hawaii and Mauritius, two country's with a long history of man induced extinctions name this bird as one of their major concerns.
In the year 2000 the International Union for the Conservation of Nature the IUCN named the Common Myna in the 100 of the worlds most invasive species.
I believe that this information is still there to be googled.

Overseas examples have only limited relevance to NZ. Sure, if we didn't have them it would be good reason to try to keep them out, but we do, and it is quite remarkable that, given all the overseas examples, they are not a real pest here too. Australia has a lot more similarly sized endemic hole-nesters.
I worry more about their affect on our invertebrates and reptiles. But then hedgehogs are likely far worse.
Jim_j
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Re: How can we save the rooks.

Postby Jim_j » Sun Jun 03, 2018 4:43 pm

Yes agree in a native forest environment then natives you would hope could hold their own - but in a modified environment - I doubt it?
So if we want kaka kakariki whitehead, tomtit rifleman etc in our towns & cities - which I suggest is a very real possibility - then impacts of myna & magpie in particular might need a bit more research

cheers
jim
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Re: How can we save the rooks.

Postby Neil Fitzgerald » Sun Jun 03, 2018 7:48 pm

Shakespeare, Tawharanui and Tiri are highly modified environments.
But I think we are getting to the same place; once we have taken care of the greatest limiting factors in some novel environments (mammalian predators, habitat quality), maybe then mynas will rise as the surface. However, it would be terrible if by the time 2050 rolls around we have completely lost some more of our endemics because we chasing around after mynas, or rooks, and diverting scarce resources from the real, known problems.

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