Morepork, native or endemic Barn owl and possible other owls here??

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.
fras444
Posts: 154
Joined: Thu Jan 10, 2013 5:06 pm

Morepork, native or endemic Barn owl and possible other owls here??

Postby fras444 » Fri May 08, 2020 12:51 pm

With lots of talk regarding Barn Owl sightings in the media and discussions on whether they should say or go...

I am curious to know the history of the Morepork here in New Zealand, the possibility of other owls or other nocturnal birds being present here in NZ as we speak and how we should treat the Barn Owl.

I am very curious to know if you regard the Morepork as Native or Endemic.... NZbirdsonline suggests that they are part of 4 subspecies of this type of owl... I'm curious to know how long have they been here for...? Longer than the Fairy tern?? and how far are they into their evolution here in NZ as a distinct species to the other three subspecies of Morkpork/Boobook and for the Morpork to be recognised as a distinct endemic species...
With nocturnal birds as such... Are there any reports to suggest that there is the odd crossing or influx of birds brought here from Australia over the last... how ever long that the Morepork have been in New Zealand for and how much genetics those birds would have passed on, that, in some sort of effect, would have kept some sort of common genetic that would essentially keep the species as a whole... some how intact....

Also on the subject of Nocturnal vagrants... What species dose Australia have that could have the and well and truly would have crossed the ditch and survived and even thrived here in NZ?? (even if it is in the same way as that long lived black kite) Any possibility that there might have been a pair that some might have bred for a year or two??? Species that look very similar to the Morepork in very poor light to the average joe blog


Regarding being a recent arrival being a coloniser, Native, a endemic subspecies ...This sort of becomes a grey area here in NZ, especially regarding how far do we go in protecting and saving species that are endemic/native... The endemic and distinct Kakapo vs the Native/endemic subspecies to New Zealand. The Fairy Tern... They arnt exactly rare in the world but.... This particular bird is kinda unique, maybe endemic on the smallest technical word of things but essentially... It is on the edge of extinction as... "A breeding species of bird in NZ" But your could argue that the White Tern was in the same situation on Raoul Island and getting ravaged by Rats, reduced to only a handful of pairs but... it didn't quite get the same amount of exposure on social media as such.
Then you add in the plight of the "endemic" Red-billed gull... Over the last decade the RB gull has been stealing some of the Fairy terns thunder on social/media as a threatened species that could go extinct in NZ and its "found" nowhere else in the world.... But it is also found as a subspecies in Australia....

There have been many comments, here and on stuff... Suggesting that the Barn owl should be eliminated and speaking of the threat that they could pose on our native wildlife...
One comment summed it all up but fell short in many ways...
"How that Barn owls could pose a significant threat on reintroduction programs and mentioned the failed attempt with the shore plovers and how the Morepork decimated that population...."
So is the Morepork essentially a "bird from Australia" that should be controlled in the name of endangered reintroduction programs... Along with the harrier Pukeko and Black-backed gull along with others... Most people would shudder at that thought (not so much with the BBed gull) Has the Morepork, Pukeko and Harrier have been here for to long to be considered as a coloniser??
The NZ falcon predates on the Takahe and along with the Morepork, could pose a risk on the rare Beatles on the brink of extinction that are found in Otago and the Long-tailed cuckoo laying its eggs in the rare Yellowhead..

What are your guys thoughts
Jim_j
Posts: 603
Joined: Sun Mar 03, 2013 1:04 pm

Re: Morepork, native or endemic Barn owl and possible other owls here??

Postby Jim_j » Fri May 08, 2020 4:18 pm

There are a few things that need to be added here....

I'm not sure anyone has suggested that Barn Owls (or Moreporks or Harriers or any other Birds of Prey) should be exterminated in NZ.
I raised two points:-
- Have Barn Owls reached NZ under there own steam or are they human assisted (either captive releases, ship assisted or both)
- When a new arrival does arrive (whether by human intervention or naturally) do we need to factor in the impact on other species and economically

If we assume Barn Owls were blown here (sorry I just don't believe they deliberately flew here) - they likely only survive here because we have modified the environment to now suit them - on this basis I suggest that gives us a "right" to consider their impact.

An apex predator such as a Barn Owl would likely have minimal effect on existing endemics - however in NZ's case there are animals at such low numbers that one more predator might be the straw that takes out a whole species.

There are already conservation programmes that control (not eliminate) native species where they impact other rarer species - weka, pukeko, black-backed gull (and I think harrier) come to mind.
I personally don't have a problem with this but I understand other people have concerns.
To me we have stuffed the place up so much that sometimes things have to be done for the "greater good" (as they say).

I raised Fairy Tern as a species that may be impacted by Barn Owls - but of course this might not be the case at all - I based it on reports of these birds preying on other shorebirds where Barn Owls have established - but as I said - when there are only 37 birds left is it worth taking the chance?
Hopefully decisions aren't based on a popularity vote - Fairy Tern or Barn Owl - sexiest bird wins...

Cheers
Jim
Davidthomas
Posts: 1103
Joined: Tue Oct 18, 2011 10:05 am

Re: Morepork, native or endemic Barn owl and possible other owls here??

Postby Davidthomas » Fri May 08, 2020 7:27 pm

I’m on the fence regarding barn owls, they’re pretty amazing animals and have essentially spread around the entire world to every continent bar Antarctica. However they’ve been proven to be serious predators in Hawaii where they were admittedly introduced. But I have reservations because they have a similar biogeography to ours, similarly rare and threatened endemics and equally altered and degraded habitats. I just think that while the population is small we should do due diligence and assess their potential threat to native wildlife before it becomes a difficult and costly endeavour to remove them.
Ian McLean
Posts: 87
Joined: Sat May 11, 2013 2:29 pm

Re: Morepork, native or endemic Barn owl and possible other owls here??

Postby Ian McLean » Fri May 08, 2020 9:39 pm

Kia ora everyone

This is an interesting discussion & I find it very odd in what appears birding xenophobia in this country. It seems that we are very happy to make sightings of vagrant birds in this country, but then some people want to start killing them when they start to naturally establish.

Some points regarding the Barn Owls are as follows:-

(1) The original captive population originated from just two birds, with a captive vagrant later added to that. The captive population died out from inbreeding in 2007 & as discussed previously the management of that captive population was poor. That someone could take them home from a zoo, breed them in their backyard aviary & release a few in the 1990's was poor stuff. However, if the current wild population was descended from those same inbred captive individuals, then surely they would have died out long ago as well. In contrast, the wild birds breeding since 2008 are very fertile, the population is growing & they appear very healthy -this indicates they are a completely new gene pool of birds.

(2) It has been reported that birds were released at Silverdale in Auckland in the 1990's & there are three records from the Auckland region at that time. A Barn Owl was seen at South Head in the Kaipara in 1990 (most likely a vagrant), whilst another was seen at RNZAF Whenuapai base in 1992 (possibly a stowaway bird) & one seen a few weeks later on Hauturu/Little Barrier Island & these two (the Whenuapai & Hauturu birds) are often considered to be the same bird. During the rest of the 1990's & early 2000's, no Barn Owls were seen or heard of in the Auckland region at all, indicating that no population resulted for the inbred captive released birds. Our Birds New Zealand, Auckland Regional Representative at that time was Michael Taylor. Michael kept very thorough detailed notes of all confirmed & possible bird sightings in our region. I have Michael's note books in my care & have thoroughly checked them for any mention of possible Barn Owls & can advise that there are no additional reports of them at all. If present, I am sure would have been noted in the 16 years between 1992 & 2008, Barn Owls being mainly white birds that are relatively easy to see & have a haunting scream like call that can scare the hell out of you !

(3) Barn Owls are the most widely distributed land bird in the world & you will naturally find them in places like the Galapagos Islands & on Western Samoa. They have made their own way to New Zealand, blown across the Tasman, just like many other native birds. Can we stop this theory that they must have hitched a ride on a ship, after all the the first three records in Barrytown 1947, Haast 1955, Rununga 1960 were on the west coast of the South Island well away from any port (excepting Greymouth as a domestic shipping port). Considering that a Willie Wagtail can be found in the Chatham Islands, please do not underestimate the endurance & capabilities of birds !

(4) Barn Owls are going to be great at controlling rats, mice & crickets. They will take a few birds, but I don't think we should unduly worry about the potential affects of Barn Owls on our existing birdlife. Jim, you seem to hold concern for NZ Fairy Tern, but when you think about it, us humans have done a pretty good job in eliminating many of the avian predators that NZ Fairy Terns had to cope with. After all the Laughing Owl, New Zealand Crow, Eyles's Harrier, Haast Eagle, the Adzebill are all extinct, whilst the NZ Falcon is largely absent from Northland/Auckland & the Weka is only in Bay of Islands on the mainland north of Auckland. The fact is that NZ Fairy Terns used to cope with many more avian predators than they do now, their near extinction is because us humans have introduced our mammalian predators & are developing every bit of coastline we can.

(5) People often say "they are only here because we modified the environment to suit them". Maybe that's true, but you are never going to change the countryside back to what it was 800 years ago are you. We changed this land & did it selfishly only for ourselves seems to be the thinking of many & how dare other animals even try to naturally establish themselves !

My message to the xenophobic birders out there is to put your shotgun away in the cupboard. New native birds (most recently Australian Wood Duck & Glossy Ibis) are arriving all the time. These new arrivals enrich what we already have & they use habitats that our endemics do not.

I am happy to have Barn Owls here in Aotearoa.

Cheers
Ian McLean
Last edited by Ian McLean on Sat May 09, 2020 10:22 am, edited 1 time in total.
Colin Miskelly
Posts: 741
Joined: Sat Jul 11, 2009 6:31 pm

Re: Morepork, native or endemic Barn owl and possible other owls here??

Postby Colin Miskelly » Sat May 09, 2020 7:10 am

Hi Ian

Have you given any thought to what will happen when barn owls reach the Chatham Islands? (as they inevitably will, once they are widespread through mainland rural landscapes).

They could potentially extirpate shore plover and taiko in short order, and possibly CI snipe and CI oystercatcher also, as well as local extirpation of Chatham petrels recently established through chick translocations on Chatham Island and Pitt Island.

This would likely mean global extinction of shore plover and Chatham Island taiko, unless at least one 'mainland' shore plover population has ongoing barn owl control in place. There is no back-up population for the taiko.

If you think barn owls are not capable of killing seabirds the size of taiko (and the smaller Chatham petrel), I suggest that you read this:

https://www.marineornithology.org/PDF/47_1/47_1_33-38.pdf

Nga mihi
Colin
Ian McLean
Posts: 87
Joined: Sat May 11, 2013 2:29 pm

Re: Morepork, native or endemic Barn owl and possible other owls here??

Postby Ian McLean » Sat May 09, 2020 9:07 am

Hello Colin

Thanks for the details of that paper, I was aware of the issue of Barn Owls predating of seabirds.

I had thought about the Chatham Islands & considered that the Subantarctic Skua there would predate any Barn Owls that even ventured near the seabird colonies there. I can imagine that any Barn Owl that made it's way to Rangatira Island would be quickly dispatched by the Subantarctic Skuas whom it seems are very territorial & do some of their hunting at night. Skuas have also taken birds the size of a Black Backed Gull as prey, so a 430 to 620 gram Barn Owl, is not really going to stand a chance.

In regard to the Taiko, the bush habitat of Tuku Reserve would seem to not suit Barn Owls at all. I think that historically many of the birds that you had mentioned survived in the presence of NZ Falcons (in the air) & the Hawkins Rail (when nesting on the ground at least on Chatham Island) in addition to the Skuas, so they are relatively robust.

It's possible that Barn Owls could survive on the open country of Chatham Island & Pitt Island & do much the same thing that Swamp Harriers, Pukeko & Weka are already doing, but in locations where there are Skua I do not see them surviving.

Colin, let me know of your comments on the above. I have only viewed Skua from a distance & you will be much more familiar with them.

Nga mihi
Ian
Jim_j
Posts: 603
Joined: Sun Mar 03, 2013 1:04 pm

Re: Morepork, native or endemic Barn owl and possible other owls here??

Postby Jim_j » Sat May 09, 2020 11:57 am

Hi Ian

Some good points - but again I would question some of your assumptions.

It is certainly possible - even probable that Barn Owl arrived here "naturally" - it is also possible that they were human assisted.
In terms of captive in-bred birds dying out - well....maybe but even from low numbers (eg Black Robin) birds may have persisted and could certainly have been a boost to any vagrants or human assisted birds.

"Barn Owls are going to be great at controlling rats/mice etc" - how often have we heard that about introduced species!!
Stoats/Ferrets to control rabbits come to mind.
It has been widely documented that food availability is the main driver of these numbers.
There are massive rodent plagues in Australia despite the presence of Barn Owls.

Yes in the past no doubt Fairy Terns coped with predatory owls - but as you say this was before we introduced a new suite of predators and degraded their habitat to a point where there are only 37 left..
Now a predatory owl may mean extinction.

Re your comment in regard to Xenophobia - well from my point a least I have no issue with self introduced birds or vagrant birds (or the human introductions we already have for that matter) - unless they pose a threat or compromise the recovery of existing species threatened due to human impact.
I note you expressed concern in the past at the impact of our NZ Grey Mallard may have on our Brown Teal populations. I would have thought this was far less serious a threat than Barn Owls may turn out to be.

Cheers
Jim
Ian McLean
Posts: 87
Joined: Sat May 11, 2013 2:29 pm

Re: Morepork, native or endemic Barn owl and possible other owls here??

Postby Ian McLean » Sat May 09, 2020 1:04 pm

Hi Jim

I was expecting your reply, for it seems that you only ever make comments on this forum. I don't see much if anything that you actually contribute in the way of sightings. But then that's kind of typical of keyboard warriors with nom de plumes isn't it.

You want to persist in believing that Barn Owls where introduced by people, that's your opinion. Generally the tactic is "the more you say it, the more people will believe it" & that's appears to have worked really well for you. When I said that "Barn Owls are going to be great at controlling rats/mice", I said that from the point that they are a naturally occurring native, not as an introduced species. Of course you know that the rat plagues in Australia are caused by heavy rainfall in the dry outback, which is not something that occurs here. In regard to Barn Owls being a threat to NZ Fairy Tern, the fact is that Barn Owls have been breeding in Northland for the last 12 years, they are widespread & I am unaware of any NZ Fairy Terms being predated in the middle of the night, apart for those killed by cats.

Jim, your obvious dislike for Barn Owls is very clear & I know that I am not going to change it. It's going to be interesting if Nankeen Kestrels & Black Kites begin breeding in New Zealand isn't it, but we will know that you will be wanting them dead.

Good to see that your checking out my observations regarding the affects of Mallard Ducks on Brown Teal & you will probably be aware of my campaign for the Grey Duck. If you dig slightly deeper, you will learn about the others things that I do & I am very happy for you to check. You can send me a personal message with some criticism & let me know from your vast experience on how you would do things better.

Cheers
Ian McLean
fras444
Posts: 154
Joined: Thu Jan 10, 2013 5:06 pm

Re: Morepork, native or endemic Barn owl and possible other owls here??

Postby fras444 » Sat May 09, 2020 2:47 pm

I think this topic is a very interesting topic which should include everyone's thoughts and opinions here on this forum and hopefully come up with a general thought and plan for what we feel should happen.... I guess a united approach for especially dealing with the greater community in education regarding this constant moving picture of colonisers from Australia... Which many people just dont quite understand.. Something that has been happening since NZ broke away from Australia/Godwanda.
When ever there is an article on stuff or any sort of social/media that has a discussion/opinions section, often... excluding the trolls... There are many comments... Bloody ozzy birds... Kill them all, we dont want these bloody ozzys killing our wildlife etc etc etc
There needs to be some sort of education, just to remind everyone... That outside of political, personal and sporting differences... NZ and Australia... whether we like it or not... Are very much connected on the natural front and since the beginning of time... We share many species or links to species... It's a simple plain fact... NZ is on the prevailing side of Australia and we had, have and will continue to be the last resort for wind-swept birds and if wasn't for that... We wouldn't of had half the birds we associate with... Even the Pukeko... A bird that is so ingrained with our society... many people are surprised to see one in Australia...

Jim_J
Regarding elimination
There has been discussions here over since this I have been following this forum and definitely the comments section on social media and amongst DOC, ecologist, university graduates doing papers and average joe blog eco workers such as myself that I have worked with... Everyone has an opinion regarding our "natives..." that sort of don't have that same prestige of the Fantail or the Morepork... birds that have been here for quite some time but still have a strong link to Australia...
Native birds that are on the cross-hairs in the name of conservation and reintroduction attempts Pukeko, Harrier, Blacked-backed gull and others and just in general.
A DOC worker discovered a Harrier learning new techniques of predating on Keruru and thinking of eliminating it before it "became a problem" in the same discussion.... It would be an fantastic idea on introducing falcons...... Some people even some of the experts just don't think that... Isnt that how we got the Eyles Harrier??? Potentially a Aust Harrier blown over here and had to learn new techniques and develop stronger muscles to predate on the mega fauna??!!! Graduate students doing a study on Tui in Tawharanui, getting concerned with Pukekos and wanted to get contractors in to control numbers because they are more flighty from people walking over the farmland and with the open hilly expanses that merge into the tops of the Kanuka canopy... that have learnt how to find tui nests in the tops of trees... An endemic bird with healthy populations and controlling a bird that is learning to adapt and learning new techniques be it human interference or not.
Wasn't this not how our birds became endemic to New Zealand and ar'nt we in a way.. Stopping that by eliminating birds that are learning these techniques and thus heading down that path of becoming an subspecies then on to becoming a completely new species..

Then there is the subject which is also one that really needs to be discussed.... Protecting a bird that is native, a very vague subspecies and a distinct subspecies... and where do we go regards with that...

White Heron.. an essentially native bird that falls probably into the not so recent native category... How much money does DOC put into protecting an essentially native "widespread and common species" globally... What are the immediate rewards apart from a cultural respect as that's what it is.. The white Heron is essentially a culturally important unique bird to the Maori.

Grey Duck... Why not put resources into this rapidly declining "sub" species...?? The Australasian shoveler once thought to be a subspecies is now no longer maybe due to its dispersed range... Lots of genetics being shared I could imagine as many these birds suggestively cross the Tasman... Is the Grey duck that separated from the Australian and Pacific population?? Would there be much genetic cross overs from Australia suggesting that this species is somewhat mobile from tagged shot birds.. How distinct is this population and where is the urge to protect this subspecies from impending extinction..

White Tern Kermadecs... Up until the recent eradication on Raoul... this species was very close to extinction as a breeding species in NZ.. The eradication was more inline with restoring this fragile environment back to what is was.. Not solely to preserve this species as a breeding species in NZ.. If Barn owls were to become established in basically an unmodified environment, I couldn't imaging DOC eradicating "a native species" to prevent another "native species" becoming extinct... Unless it was a distinct endemic species that was rare due to mans involvement

Pied stilts... I had heard of discussions over controlling populations around Black stilts main/only breeding location.. I've heard other experts suggesting how old is our Back stilt in an evolutionary scheme of things apart from the Pied stilts and whether they could have all hybridised had man not arrived in NZ in the first place with the prolific nature of the communal Pied stilts

Now to the Fairy Tern and whether we should cull Barn Owls...
The Fairy Tern globally listed as vulnerable....
On the scale of Subspecies.... where dose this bird fit on the scale?? Is it an ancient Morepork/Fantail subspecies... A more of an in-between Red-billed/Pied shag thing or is it more of a recent separation... could be in the same scale as a Grey Duck/Kingfisher or right at the end with the Aust Shoveler...
Are the birds distinctly separated from the Australian birds... Are there any genetic cross overs from Australia? are they technically and endangered species or just a rare "native species in NZ" that would become a extinct species breeding in NZ much like the Horay Grebe...
I personally would love the Fairy Tern to continue to be a "native" breeding species. I understand that it is a genetically different subspecies to the birds found in Australia.. but how distinct that remains to be researched...
But for it to be a deciding factor regarding the Barn Owl... Fairy terns and Barn Owls co-exist in Australia anyway... I'm not too sure...
User avatar
philbattley
Posts: 564
Joined: Wed May 20, 2009 2:21 pm

Re: Morepork, native or endemic Barn owl and possible other owls here??

Postby philbattley » Sat May 09, 2020 3:11 pm

If Barn Owls do establish more widely on the mainland and if they do make it to the Chathams I am sure that the powers that be would be well within rights to control them, assuming they can find them. So we birders had better figure out how to find them on the mainland once the lockdowns ease so there will be a skilled cohort of expert owl spotters ready to help assist in 30+ years time...

Colin Miskelly wrote:Hi Ian

Have you given any thought to what will happen when barn owls reach the Chatham Islands? (as they inevitably will, once they are widespread through mainland rural landscapes).

They could potentially extirpate shore plover and taiko in short order, and possibly CI snipe and CI oystercatcher also, as well as local extirpation of Chatham petrels recently established through chick translocations on Chatham Island and Pitt Island.

This would likely mean global extinction of shore plover and Chatham Island taiko, unless at least one 'mainland' shore plover population has ongoing barn owl control in place. There is no back-up population for the taiko.

If you think barn owls are not capable of killing seabirds the size of taiko (and the smaller Chatham petrel), I suggest that you read this:

https://www.marineornithology.org/PDF/47_1/47_1_33-38.pdf

Nga mihi
Colin

Return to “General Birding Discussion”