John, Peter,
I'm using "we" as shorthand for the Canberra community.
I can't help you with current trap density figures for Gungahlin. A year
ago there were 70 registered traps in Gungahlin and Michell, 20 of which
had already been there for 4 - 6 years. Such long exposure to trapping
leads inevitably to high levels of trap- and human-avoidance, as
indicated by John's careful observations of changes in the behaviour of
his local myna population.
John, all the best with your trapping. Remember that the foraging trap
is an imperfect sampling tool; the size and composition of its collected
samples depends on the proportion of trap-naive individuals in the
population. No matter how much we might wish to turn back the clock to a
time when Peter and other forage-trapping pioneers were able to remove
large numbers from populations in which all age-classes were trap-naive,
we can no longer expect our samples to contain a significant proportion
of experienced breeding adults. No matter how much trapping we throw at
trap-avoiding breeding birds, we won't remove them or their bulky nests
from the hollows on Percival Hill or in the Dunlop Grasslands Nature
Reserve - unless we put equal or greater effort into other interventions.
If you find, as I expect you will, that your trapping does not improve
the circumstances on Percival Hill, please don't think there is nothing
more you can do. There are a few things we could all do:
- encourage others to consider what contribution they can make;
- be prepared to admit that this problem is not yet under control, and
that we need to be at least as adaptable as the mynas;
- encourage community members to take an interest in the condition of
hollow trees in their neighbourhood and to contribute to important
initiatives like COG/CIMAG's new survey of myna nest-sites;
- encourage land owners/ custodians to take responsibility for myna
nests on their properties;
- encourage Canberra's research institutions and citizen-science
communities to step up their efforts to better understand this species.
For example, we know almost nothing about the annual dispersal from
Canberra's breeding population into the surrounding countryside. Our
relief at their departure at the end of the breeding season, and our
agitation at their return at the beginning of the next season, are both
reflected in the shape of the graph in the top-right corner of
http://canberrabirds.org.au/wp-content/BirdSummaryData/Common%20Myna.pdf. But
we have no idea how many travel each way or where and how far they go. A
simple mark-recapture programme would give us this and other important
information. Trapper/ observers on the suburban fringe, like John, could
be major contributors.
Peter, we will only answer your question about the effectiveness of nest
removal by trying it - preferably on a broad scale. We will certainly
achieve nothing by leaving the nests in the affected hollows. There is
excellent evidence that mynas learn to avoid a dangerous situation when
they can observe its cause, while they don't learn if they can't observe
the cause. Putting it another way, if we disturb their nests in daylight
while they watch, they are more likely to desert the nest-site than if
we disturb the nest at night when they can't watch. This knowledge could
underpin a programme in which we discourage nesting in hollow trees by
conspicuously removing nests and eggs in daylight, while we encourage
nesting in nearby nestboxes from which we remove only eggs discreetly at
night. In this way, we would shift the breeding population from hollow
trees that are difficult manage, except by specialists, into nestboxes
that are readily managed by people even more frail than John and me.
In my neighbourhood, a few of us have started a campaign to drive
untrappable nesting mynas out of local hollow trees. We are being
supported by two enthusiastic CIMAG members, one of whom is an expert
climber. We removed three nests and a clutch of eggs in the past
breeding season, and we are prepared to continue doing so until the
mynas get the message. The cost so far has been a couple of hours of our
time; our reward to date is foiling at least two myna breeding attempts.
For my part, I will be more than delighted to host a controlled breeding
pair of mynas in one of my nestboxes if it increases the chances of
Red-rumped Parrots and Kookaburras returning to my neighbours' hollow
trees. A few more small neighbourhood projects like this, and perhaps a
couple of large ones coordinated by government agencies and research
institutions, could add up to something valuable.
Whether we can recruit other climbers to help might depend on the
messages we send to the community. If we indicate by assertion or by
implication that there is no need to deviate from our current course, we
encourage indifference within the community and in governments. If our
message is narrow and indicates that trapping is the only contribution
worth making, we will lose the interest of those for whom trapping is
impractical or distasteful. I know there are keen young Canberra people
with climbing expertise and an interest in wildlife conservation who
would relish being involved in myna control if they were aware that
their expertise could make a contribution. Unless we tell them
otherwise, they are likely to believe, like many other Canberrans, that
the problem is already under control.
Daryl
On 4/08/2014 10:41 AM, Peter Ormay wrote:
John and Daryl
Removing nests wouldn't stop them building another one I don't think but
this needs testing or is there evidence that it does? Removing chicks
certainly doesn't stop them laying another clutch. A couple of years ago I
removed a clutch of advanced chicks from a nest box in the Pinnacle NR
behind the houses in Hawker while checking the nest boxes after Kate
Grarock's PhD study was finished. They had laid another clutch a month
later.
The mynas have been removed from the eastern and most the western part of
Aranda through trapping alone I think. I did the nest box checking in Aranda
for Kate's PhD study and no-one to my knowledge removed any myna nests from
the nest boxes in the area.
There was a group of about 6 mynas in the Aranda Snow Gums area and a
similar group south of the Bindubi St x William Hovell Dr intersection as
well as one in the Aranda Bushland south of Mirning Crescent before the
trapping started. These groups disappeared once the trapping got going. I
think they went back into the adjacent suburbs once the myna numbers there
thinned.
It is heartening to know there are lots of traps in Fraser but trap density
does not necessarily mean trapping activity. People stop trapping for
various reasons. We need someone to check how many people there are still
trapping.
What is the trap density in Franklin, Harrison, Palmerston, Crace, Ngunnawal
and Nicholls and adjacent to Mulligans Flat in Forde?
Peter
-----Original Message-----
From: John Harris
Sent: Monday, 4 August 2014 9:18 AM
To: Daryl King; Peter Ormay;
Subject: Re: [canberrabirds] 30 superbs at the mosque
Of course you are right Daryl but the truth is that I am doubtful enough
that ‘we’ (whoever that really is) could actually recruit people to remove
nests but I hope I am wrong. I am too old or I might have tried already on
Percival Hill. We need to do what little we can in the most strategic way.
What I feel is that we should at least try to trap mynas which forage on the
edge of suburbs like mine which border more natural environments. I have
observed them naturalised on Percival Hill and they fly there when
disturbed.
On 3/08/2014 7:13 pm, "Daryl King"<> wrote:
Peter,
The last time I checked (a couple of years back), Fraser already had
the 17th highest density of traps in Canberra (out of 91 suburbs with
registered traps). At 5.6 trap-sites per km2, Fraser's trap density
was then already well above the average density of 3.7 traps per km2.
For comparison, trap density in Fraser was then about the same as in
Aranda, and was higher than in Chapman (5.4), Melba (4.8), and Kambah
(4.7).
The problem that we want to address here is the mynas' monopolising of
nest cavities. There would seem to be little point in increasing the
use of a method that targets only the mynas' foraging behaviour -
especially in circumstances where an increasing number of mynas are
able to avoid or defeat our foraging traps - while doing nothing about
its nesting behaviour.
Mynas do not continue to nest in places where their nests are regularly
disturbed. We know that because we can stop them nesting in our roofs
and nestboxes by removing their nests. If we put our minds to it, and
recruit some people with the necessary skills and training, I'm sure we
could develop a system for strategic removal of myna nests in priority
areas. Mynas are excellent judges of risk, and would quickly get the
message. In any event, their bulky nests would have to be removed
before Superb Parrots (or any other parrots) would use the affected
cavities.
Daryl
On 3/08/2014 6:25 PM, Peter Ormay wrote:
Do any COG members live in the areas where Superbs have been recorded
who would be willing to operate a myna trap to reduce the competition
they pose to the Superbs?
Peter
-----Original Message-----
From: Daryl King
Sent: Saturday, 2 August 2014 7:08 PM
To:
Subject: Re: [canberrabirds] 30 superbs at the mosque
Some good news: Despite successive waves of irresponsible clearing,
northern Belconnen (including the area covered by Fraser) still
contains quite a few hollow-bearing remnant eucs - mostly in a band
above the 600 metre contour (see attached (incomplete) map). Superb
Parrots have inspected hollows throughout the area in each of the
past three breeding seasons.
Some bad news: 1/3 to 2/3 of hollow trees in northern Belconnen are
occupied by Common Mynas each year. In those circumstances, it is
highly unlikely that Superb Parrots will re-establish a breeding
population there.
Daryl
On 2/08/2014 1:20 PM, Mark Clayton wrote:
In the late 1960's, early 1970's Superb Parrots were a common
species in the area that is now covered by the suburb of Fraser. I
used to know people who owned a property there and Superb Parrots
commonly bred in some huge old Yellow Box trees. There was also what
was probably Canberra's last colony of Grey-crowned Babblers present
on site. The parrots then appeared to die out for quite a while and
it is only in the last decade that they appear to have made a
comeback to the northern part of the ACT. How long they will stay
remains to be seen as they do tend to follow food resources around.
The breaking of the drought has probably had quite a bit to do with the
birds return.
On the other hand the ACT Government has done nothing to help them
by clearing large areas of suitable habitat for housing. From
memory, someone once said that of the 95 mature Yellow Box and Red
Gums in the now
suburb of Crace, 80 were removed for housing. Several years ago I
travelled along the road that borders Mulligan's Flat NR and was
horrified to see that every tree up to the reserves' boundary had
been flattened. As I pointed out to Chris Davey at the time he was
doing surveys to record breeding sites for the parrots, it is a
totally useless exercise to find nests if all their food trees are
being knocked over. This is what is happening with Regent Parrots
along the Murray River. They breed in the River Red Gums and feed in
the mallee which is still being cleared for agriculture. They are
having to move
further and further to find feeding sites.
I will be interested to see what happens with the Superb Parrots as
Canberra continues to move into critical habitat in the newer
Gungahlin suburbs. The ACT Government plans for so-called "offsets"
is a farce and so is their so-called "solar orientation "policy
which is one of the reasons the trees
in Crace were removed. All the old Eucalypts near the Gungahlin Town
centre will be dead within the next 50 years and nothing appears to
have been done to start potentially replacing them. As soon a
building goes up near them they will be removed as potential hazards.
The older I get the more cynical I become about governments and
their "environmental" policies. I don't think any of them really have a
clue!
Mark
-----Original Message-----
From: John Harris
Sent: Saturday, 2 August 2014 12:18 PM
To:
Subject: Re: [canberrabirds] 30 superbs at the mosque
It¹s gratifying to see the Superbs becoming more visible in Gungahlin.
They have been nesting here in Mulligans Flat for years but were
rare in Gungahlin suburbia until the last couple of years and now
quite large flocks this year. They visit Percival Hill now in
numbers and I put it down to the maturing of the trees planted by
landcare folk in the late 1990s which are
now virtually a mature woodland environment.
On 2/08/2014 11:57 am, "Peter Ormay"<> wrote:
Hello Chris
Yesterday 1-8-14 I watched about a maximum of 30 Superbs near the 3
large Yellow Box trees E mell. at the South end of Kate Crace St
from 9.20am to 10.30am feeding on the ground mainly in native
dominated vegetation in strong cold west wind. I could not see what
they were feeding on due to the height of the grass.
It included a female-looking bird with yellow flecks on its back.
The numbers fluctuated as flocks of 8 to 15 SPs flew off South and
NE but seemed to return. They seemed skittish while on the ground,
possibly due to the strong wind, flying up into the adjacent Yellow
Boxes at any disturbance such as a Wood Duck nesting in the Eastern
Yellow Box flying over them but they soon came down again.
They were feeding mainly between the northern fence (with plain
wires) and the inner (with 2 barbed and 3 smooth wires) fence. They
also fed south of the inner fence but all within 20m of the Yellow
Boxes
Peter Ormay
-----Original Message-----
From: Bill & Raelene
Sent: Sunday, 20 July 2014 12:22 PM
To:
Subject: [canberrabirds] 30 superbs at the mosque
Gungahlin Town Centre survey with Angela Plant today. 30 Superbs
0910-0930 in large eucs beside mosque site , sth end Kate Crace St.
Feeding on the ground, noisy, hanging about, roosting site? Low
morning sun gives them a startling, flouro green glow. Total 21
species.
Bill Graham
*******************************************************************
**
**
***
**
***************************
|
