Another bivalve victim (moderated)

To: David Stowe <>
Subject: Another bivalve victim (moderated)
From: Ian May <>
Date: Thu, 28 Feb 2013 09:17:16 +1100
Thanks David

Yes, there are many disturbance factors that cause alarm to waders and I agree, raptors, dogs, people, 4wds etc. are all problems. But waders appear to cope with most of that because presumably they see the threat coming. However the shock and stress levels inflicted on birds from Cannon-netting and subsequent handling are clearly in a much more severe class of their own. The proliferation of cannon-netting around the entire flyway is more than likely to affect most waders either by their actual capture or their proximity to the attack. In most wader flocks there are bound to be some if not many birds that will have experienced the horror of cannon-netting/handling etc.. If you have ever observed the extreme skittish behavior that develops almost overnight with wild ducks after the opening of the duck season, you will understand the behavior I am referring to.

It is the surprise shock of the attack that is most likely to be the cause of the developing feeding/roosting aversion behavior in migratory waders. I could go on about how generally approachable waders were before cannon-netting compared to current patterns but that would be considered anecdotal. It should suffice to say that 7 x 50 binoculars were sufficient equipment for wader observation before cannon-netting but now one is lucky if you can get close enough with a scope. Anecdotal accounts/evidence should not be dismissed so easily. It's validity is about the same as accepting data evidence from a source that is operating because of a financial incentive to undertake the research. In this regard the Shorebird 2020 exercise appears to be offering a potential gravy train of funds for pro banding researchers when the real need for financial support is for acquisition of wader habitat. Without wanting to drag other contributors into this, I agree with the recent post by Chris Baxter from Kangaroo Island about the need to protect habitat. See who put the case far more eloquently than I ever could

Regarding mechanisms for a study to determine impacts from banding/flagging/cannon-netting migratory waders, I have previously written study outlines of minimum considerations required and held discussion with officials from the Cannon- netting fraternity about this.. As suggested in a previous post, we could soon put together a group to negotiate project objectives that would satisfy the obvious need.

Unfortunately, I have another life outside of all this so for the time being, I think that's about it from me. Thanks everybody for your tolerence.


Ian May
PO Box 110
St Helens, Tasmania 7216

I have been reading all this discussion with alot of interest and it certainly 
has caused alot of emotion to come out.
I have also been trying not to comment as I don't want to add to anyones stress 

However i do find it interesting Ian that you want more scientific data, but 
don't want to accept the data already there - instead you would rather trust 
your own personal anecdotes/experience?
I think you also attribute too much emotion perhaps to the "pro canon netters". 
They have scientific data because they are quite scientific about it rather than 
emotional or anecdotal. I think that those in favour of flagging etc would give it up at 
the drop of a hat if they found that what they were doing was causing more harm than good 
so I'm not sure that attributing an emotional bias towards them is very accurate.

Personally i can see both sides of the debate and I do think it is a debate worth having, although i'm really not sure how an independent review into mortality rates would be any different to the results obtained by the wader studies groups? Is any sort of study truly going to be "robust enough" to satisfy the emotions of those so opposed to leg flagging? Quite honestly i doubt it.
What would be the mechanics of such a study? Would it be to band some and see 
if they make it back next year? Isn't that what is being done already?
I am genuinely interested in an answer to this and not just trying to prolong 
the debate.

In terms of the birds becoming more skittish; wouldn't it be much easier and 
more likely to link this to pressure on lack of habitat and more encroachment 
on their feeding grounds by people in general? Surely there is alot more of 
that than Canon netting? My own anecdotal evidence would show the ratio of 
birds disturbed by people/dogs/raptors at thousands to one compared with 
netting/flagging. In the last 10 years I've only witnessed canon netting once 
and banding of tern chicks a couple of times but in half a day photographing 
waders at Shoalhaven Heads (NSW) i saw the flock put up by raptors or people at 
least 10 times.

David Stowe

On 27/02/2013, at 7:43 PM, Ian May <> wrote:

<>Thanks Stephen

I also said

"To avoid any possibility that such results could be skewed or biased manifests from 
statistical manipulation and to help put this leg flagging debate to rest, at least one if not 
more, independent scientific studies need to be undertaken; " specifically based on 
project objectives designed to test/identify the survival rate, mortality and negative impacts 
from leg flagging/banding/radio tracking/cannon netting on small migratory waders (i.e.. birds 
no larger than Sanderling). "   This is what we are asking for and if the results were 
corroborated and verified by a robust field study (not just reviewing existing statistics) 
designed to identify banding impacts, that would be a great outcome and we could put the 
matter to rest

<>My comment "not robust enough" was is in the context of what adequate data is 
required to satisfy the concerns of those who are gravely concerned about the impacts of leg 
flagging migratory waders.
The statistics are I presume from their existing data base supplied mainly by 
the same pro bird banding group subject to the criticisms.  The reply was  in 
response to previous discussions and a request to instigate a study into the 
impacts of banding.    The results supplied can hardly be accepted as an 
example of unbiased independent review.

Obviously as an individual i do not have access to the same levels of information as the pro cannon netters/leg flaggers and I agree, their data sets are impressive and would provide a great comparison for verification from an independent review into banding impacts. But what I do have however is nearly fifty years of field experience watching waders and I have seen adverse impacts personally not only in the physical damage caused to some of the birds by leg flagging but also from an emerging feeding aversion behavior demonstrated in many waders in recent years. This flighty, easily disturbed characteristic appears to be developing, probably in response to the startling fright and stresses caused by cannon netting and the further stress that follows during the subsequent handling. Some would argue that more timid behavior could be an advantage to help these birds in other places, but what i see are more birds more easily disturbed than ever before. When waders are more easily disturbed from their feeding and roosting areas when attempting to build their energy reserves and rest prior to migration, it could have a hideous effect on success of their migration even without the added burden of bands.




Stephen Ambrose wrote:

Ian said:

" I have studied Clive's response copied below and I thank him for this and fully 
accept many parts of the reply that are clearly correct, however the stated conclusions 
about survival rates of small migratory waders after banding are based on statistical 
data not robust enough to be used adequately for such conclusions, nor collected for the 
purpose in a project environment designed to test banding impacts."

Ian, could you please explain to us why you think the statistical data
presented by Clive are not robust.  The sample sizes for each treatment
(metal bands, metal bands + some flags, metal bands + lots of flags) are
very large (5,489 to 11,258), yet calculated annual survival rates
associated with each treatment are very similar. Most
zoologists/ornithologists/field ecologists/biostatisticians would be envious
of such large data sets.

How did you reach the conclusion that the data are skewed, biased or
statistically manipulated? From reading Clive's response, I don't see any
evidence of this.  Perhaps I am missing something, so would be delighted to
hear your explanation. Kind regards, Stephen Stephen Ambrose Ryde NSW

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