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Birds + cannons = good science

January 16, 2013

Hanging around the Miranda Shorebird Centre harassing sparrows comes with occasional advantages, and one of those is that you get to hear about all of the cool stuff that is happening at the Centre and, if you’re lucky, tag along.

For the last week, Miranda has played host to a field course: a week of intense training in bird conservation and science for a collection of 15 or so students. Some from regional councils, some tourists, some mildly-obsessive twitchers. Some who tick several of those boxes. By hanging around and talking to people, N had managed to find out that there was some cannon-netting as part of this course, and that a sufficiently sneaky individual could tag along to help. So, N and I loitered around the place we knew cannon-netting people were going to be, hoping to coincidentally bump into them. At seven in the morning. Not suspicious-looking at all.

Cannon-netting, for those not in the know, is one of the coolest field ecology techniques. It involves using several hidden cannons to throw nets over a sitting flock of birds, catching the whole flock in one manaical swoop. Good fun. The setup looks something like this:

Cannon netting schematic

Now, mentally add 25g of black powder to each

Cannons, and cannon projectiles.

The cannon-nets were already set up when we arrived, and a large mixed flock of wrybill, sharp-tailed sandpiper and curlew sandpiper were sitting nonchalantly in front of them. Instructions were given: “when you hear the charges go off, run like the blazes towards the nets, and throw hessian sacking over the birds to stop them from panicking, then start working to get them into boxes for processing”. Amid back-and-forth chatter on radios, we started out towards the unsuspecting flock.

One ‘boom’ later, everybody broke into a run, threw hessian over struggling netted birds, and then started extracting them into boxes. A slight misfire meant that one of the nets was tangled on itself, so the catch was not as high as expected, but there were still what looked like 80 birds caught. Mainly wrybill, plus three sharp-tailed sandpiper and one curlew sandpiper. Success!

"boom" + 10 seconds

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Now, the reason we got to play around with cannons is that Miranda is the site of a quite intense band-recapture monitoring effort, which generates data on where shorebirds of different species go, when they go, and what places they stop on the way, as well as life-history parameters like maximum longevity. So next up was the task of taking sorting all of the birds by species, ringing them, and recording their weight, wing length, and moult stage (which can be used to estimate age). The group split up into sub-groups, each under the guidance of an Elder Statesperson of Netting, and started processing birds. It was an occasion for a great deal of photography.

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Shane Baylis with wrybill

I have no recollection of pulling this face

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Sandpiper in a tube. Because screw individually bagging birds, if you've got a lot of them to weigh.

Sandpiper in a tube. Because screw individually bagging birds, if you’ve got a lot of them to weigh.

Nancy Van Nieuwenhove with wrybill

Moult checking. It might not look like much, but a skilled person could tell me how old this bird is, based on this picture.

The banding process was, somewhat embarrassingly, a new experience for me. I have handled plenty of birds before, either captured by mist-net or by hand from burrows, and have taken blood samples and microchipped them or marked them with paints to ensure against multiple recaptures during a short-duration study, but I’ve never had occasion to attach an actual classic metal band to a bird before.

Shane Baylis with wrybill

You are *my* wrybill, CP3018.

It’s quite an easy process, but the stage where one squeezes the ring closed, using pliers powerful enough to crush the bird’s leg into tiny shards if it jerks its foot at the wrong time, can cause some fractiousness.

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You know, like *this*...

You know, like *this*…IMG_3457wm

However, (fortunately) no-one crushed any legs, and all the birds were released to go, preen, act indignant, and quite possibly get recaptured next year.

Run, little bird! The monster didn't eat you this time, but that's not to say it won't in the future!

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From → Scientist

2 Comments
  1. Stella permalink

    I imagine it is actually rather difficult to look suspicious in a prime bird-watching area.

    • …yeah. It’s hard to be suspicious, also, when people wave and say hi when they see you. Oh well!

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