birding-aus

Cannon Netting

To: frank o'connor perth <>, "" <>
Subject: Cannon Netting
From: martin cachard <>
Date: Thu, 23 Oct 2014 20:07:56 +1100
well said Frank!! 
& beautifully written too I might add...
 
cheers,
martin cachard,
cairns
 
 
> Date: Tue, 21 Oct 2014 20:42:53 +0800
> To: 
> From: 
> Subject: [Birding-Aus] Cannon Netting
> 
> 
> It still annoys me when I read criticisms of cannon netting.
> 
> I have been a member of 15 or more AWSG North West Wader Expeditions 
> over the past 20 years as a (paying) volunteer, and I certainly plan 
> to join future expeditions when I am available.  I am not a 
> bander.  I am not the one who summarises the data and publishes 
> papers.  But every expedition I see the dedication of the people who 
> are involved full time on the study and conservation of 
> shorebirds.  I join each expedition as an assistant, often making the 
> leg flags, as a spotter in the hide and often the leader of a process 
> team. I learn more about shorebirds on every expedition that I 
> join.  The shorebird families are always high on my want to see list 
> when I travel overseas.
> 
> I have seen many important and useful outcomes from the expeditions. 
> A few are :
> 
> 1. Satellite Tracking of Bar-tailed Godwits.  I admit that I was 
> shocked when I understood how this was done.  The waders are caught 
> in cannon nets (this was not a significant threat and I was part of 
> the team that made the catch), but then the birds were taken back to 
> the Broome Bird Observatory where they were surgically implanted with 
> the transmitters, with the aerial protruding from the tail.  Surely 
> this can't be good?  Well all Bar-tailed Godwits survived and were 
> released, transmitted their data for a year or more (until the 
> battery gave up) giving important insights into the behaviour and 
> movement of these birds (local movements, movements within WA, 
> stopovers for some, feeding stopovers, breeding areas, post breeding 
> areas), and they were all back in Broome the next year.  This was 
> after this was first done in Alaska, and then in New Zealand so the 
> people involved had experience with how to look after the 
> birds.  This amount of new information learnt could not have been 
> achieved in any other way.
> 
> 2. Satellite Tracking of Little Curlews.  Similar to the above, but 
> the satellite transmitters were attached by harness.  Very little 
> information was previously learnt about this species by band and flag 
> sightings (mainly local movements) because they are not monitored on 
> the rest of their migration cycle.  So it was not well known where 
> they stopped over, where they bred, etc.  This information was 
> disseminated very soon after the satellite data was processed every 
> few days, and it was a major part of BirdLife Australia's event on 
> increasing the awareness of shorebirds in April this year.
> 
> 3. Geolocators.  This is fascinating.  A small one gram device is 
> attached to a large leg flag.  It records the location of the bird at 
> defined periods for as long as the battery lasts.  The difference 
> from the transmitters is that you must recatch the bird to retrieve 
> the geolocator to analyse the data. So this has been used on birds 
> that have a high site fidelity such as Ruddy Turnstone, Greater Sand 
> Plover and to a lesser extent Red Knot and Great Knot.  The results 
> are amazing and show the migration paths and breeding areas.  Some 
> birds have had a second geolocator attached after the first has been 
> retrieved, and this allows two years of data to be compared for the 
> same individual.  Do they use the same migration path?  Do they use 
> the same stopover site to refuel? etc, etc.
> 
> 4. Colour Bands.  I admit that I had doubts about the usefulness of 
> this technique.  As part of the Global Flyway Network project, 
> Bar-tailed Godwits, Great Knots and Red Knots were banded with four 
> colour bands (two each leg), one yellow leg flag (YLF) and the metal 
> band.  We had been using plain YLFs, and then yellow engraved leg 
> flags (ELFs) and I thought that this was enough to read the flags to 
> get the information they wanted.  Then as part of the expedition we 
> spent a day searching for and recording the ELFs and colour bands in 
> Roebuck Bay.  The colour bands are much much easier to read.  You can 
> see them from any angle.  You can see then through the legs of other 
> birds.  You can see them from further away.  ELFs must be birds in 
> the open and the flag needs to be side on and you need to be 
> relatively close to the bird.  Three or more people through the GFN 
> then spend six to eight weeks each year on the feeding sites at the 
> Yellow Sea monitoring the birds passing through.  This gives enormous 
> information about how and where these birds feed.  It shows that you 
> can't just protect one important area.  Birds move between them, and 
> so you need to protect them all.  It gives information on 
> mortality.  It gives information on population sizes.  It shows local 
> movement within Australia, giving information about how some sites 
> interconnect.
> 
> This combination of six items on a bird is the most that I am aware 
> of.  As far as I am aware the most that are used on the smaller 
> waders (including Curlew Sandpipers) are two legs flags and a metal 
> band.  So when I hear hearsay reports of them having seven items, I 
> want to see the evidence.  Date, place, colours and preferably a 
> photo.  But each time this claim is made, no evidence is produced. So 
> sorry. I don't believe it.
> 
> Without this specific data on the movement of individual birds, 
> governments won't listen.  This data from leg flags and colour bands 
> puts more pressure on the governments in the flyway to uphold their 
> obligations under the various migratory bird agreements.
> 
> 5. Cannon Netting.  The teams and the procedures are very experienced 
> and detailed now.  Yes, unfortunately there are still a few birds 
> injured at the time of firing.  And this hurts the members of the 
> team.  These  casualties are reported on the catch summary 
> sheets.  The birds are frozen, and sent to the WA Museum.  They can't 
> hide the casualties.  There are too many volunteers.  I understand 
> that the 'acceptable' casualty rate is 1%.  Maybe early on this 
> happened.  But casualties are uncommon and we usually achieve 0.2 to 
> 0.3% over the course of a three week expedition (about 4,000 
> birds).  With the new small mesh nets, the birds are very quickly 
> removed from the nets and put in keeping cages covered by shade 
> cloth.  Under the hot conditions at Broome, we need to process and 
> release the birds within about three hours of the catch.  This is 
> always achieved.  Why are the birds caught?  Our first goal each year 
> is to catch enough of 10 key species to be able to estimate the 
> breeding success (by determining the percentage of juveniles in the 
> population).  This data is important in monitoring rises and 
> especially falls in the populations.  There is a fairly high 
> recapture rate.  These birds give information about the age 
> distribution of the population and allow better estimations of the 
> total population.  They give information about the movement of the 
> birds.  For some species, it shows that they are quite highly site specific.
> 
> 6. Blood Samples.  I still have some reservations about this.  Some 
> birds do struggle when they are released, and do need to be kept 
> longer to recover.  The blood samples are taken by AQIS for 
> monitoring avian diseases in Australia.  Yes, cloacal swipes are also 
> taken.  During the hysteria of the period when bird flu was an issue, 
> these samples showed that this was not an issue for Australia.  There 
> are a few casualties of birds that have been bled.  Even though this 
> is not directly due to the normal cannon netting process, they are 
> included as casualties in the catch report.  The government would 
> want some sort of a measure anyway on avian diseases, so it is better 
> that the testing is done this way, than through other more drastic 
> methods one could think of. Only a small percentage of the catch is 
> sampled, and samples are taken on only a few of the catches in 
> Broome. Blood sampling in the past has also been used for DNA 
> analysis, sex determination and other purposes.
> 
> 7. Isotopic analysis of Feathers.  This is fascinating.  If you know 
> when during the migration cycle that a bird grows a particular 
> feather (say a secondary covert), then by sampling that feather you 
> can determine to a large extent where the bird was at that 
> time.  This adds to the information from other sources of how birds 
> move and where they stopover.
> 
> 8. Declines in Populations.  It is claimed that the declines are due 
> to cannon netting.  But this is demonstrably untrue.  The age 
> analysis of the birds caught show this.  The Shorebirds 2020 surveys 
> at sites where there is no cannon netting show this, and the number 
> of flagged birds in these areas are very low.  The birds caught show 
> a high site fidelity.  But the people making the claims do not read 
> the papers, or the survey analysis.  I guess the less you know, then 
> the more things that you can imagine might happen, even if they have 
> already been proven to be untrue.
> 
> 9. Raptors.  It is true that some birds in the past have been caught 
> by raptors as they are released.  But the procedures have been 
> changed and there were none on last year's expedition.  There are 
> lookouts posted for raptors.  Birds are released in groups rather 
> than individually if there is any risk of raptors being around.  It 
> is everyone's responsibility to lookout for raptors. I don't believe 
> that this is an issue any more.
> 
> 
> Where do I learn about these things?  By being a participant in the 
> expeditions.  By being a member of the AWSG.  It is sent by 
> email.  It is published in Stilt and Tattler (published by the 
> AWSG).  It is published in international journals.  It is on the AWSG 
> web site.  It is disseminated at shorebird conferences.  Some of it 
> is communicated on the GFN web site.  This information and much more 
> is available through cannon netting, and it does further the 
> conservation of these species.
> 
> There are vacancies for next year's expedition.  You do not need to 
> be a member of the AWSG.  It is not a holiday!  There are early 
> starts, heat, humidity, lots of other tasks.  But there is some time 
> for general birding.  We look for a team of 23 to 25 people so we can 
> safely catch 250 to 300 birds in a catch.  If we catch less then we 
> fully process each bird (band, flag, age, moult, weight, wing length, 
> etc). If we catch more then we reduce the amount of processing so 
> that the birds are released well before the three hour limit (at 
> least band, flag, age).   There are tasks for people of all levels of 
> experience and fitness.
> 
> The people involved in cannon netting care more about these birds 
> than anyone, and do everything they can to promote the conservation 
> of these species. They put their time into it.  It is grossly unfair 
> for them to be criticised.
> 
> 
> _________________________________________________________________
> Frank O'Connor                          Birding WA 
> http://birdingwa.iinet.net.au
> Phone : (08) 9386 5694               Email :   
> 
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