You may, or quite understandably may not, know that a lot of
research on bird migrations and populations has involved putting a small,
individually numbered metal ring on the bird’s leg. This has been done for
years, by experienced, serious and (no doubt) highly intelligent researchers,
but also by a significant number of amateur birders for whom it’s simply a
hobby. Whilst this system has thrown up some mind-blowing data over the years,
it inherently relies on a ringed bird somewhere down the line either being
re-captured or being found dead (or shot in some species..) simply
because the rings are small, pretty inconspicuous and almost impossible to read
on a bird hopping about in the wild.
A bit of a game-changer is the use of individually coloured
or coded rings. This allows known individuals to be re-sighted from afar,
whilst free and alive; opening up a realm of research opportunities.
Coded Greenland white-fronted goose neck collars ready to be deployed
But you have to catch your chickens before you can count them. Sorry. With almost every type of bird comes a method of catching them. And whilst mist nets and clap traps sound exciting, there is only really one way to cook your goose, so to speak – to cannon-net it. It sounds spectacular, and it is. Anything using a lot of black powder, projectiles and 1000 volts is pretty much guaranteed to be. It sounds easy, and it’s not. Which is a major reason why this blog post comes some time after the previous one – we’ve been trying to catch the Greenland white-fronts. And we struggled.
WARNING: The video clip makes
it look easy, but then they (Prof Stuart Bearhop – my Masters supervisor at the
University of Exeter – and the Irish Brent Goose Project) were catching brent
geese. And there are lots of them. And they’re a little bit thick. More on them
in a future post..
The beauty of catching geese is that we can individually
mark them with leg rings and neck collars. By subsequently re-sighting and
identifying these marked birds, they then can tell us all sorts of information
about that individual, from life expectancy and survival rates, to migration
routes, to small everyday details, like
which fields they like to feed in when – even which social network it belongs
to!
Coloured and coded leg rings on light-bellied brent geese in Iceland - the subject of a current study on social networks within flocks
Every white-front that gets caught receives a fair bit of
jewellery, as well as being thoroughly weighed, measured, swabbed and sexed.
First is a small metal ring which is issued by the British Trust for
Ornithology (BTO) – every bird that gets ringed anywhere in the UK will have
one of these – but then comes the bling. Each white-front then gets a white plastic
leg ring and orange neck collar, engraved with an individual 3 digit alpha-numeric
code. From now on, that goose can be recognized wherever it goes, and if the
sightings are reported and collected we can slowly build a picture of what it
gets up to.
Collared and ready for release - the story begins!
The re-sighting process can vary from being infuriatingly
difficult to a walk in the park (literally in the case of Dublin brent geese). It
is immensely rewarding though and strangely addictive. There are many levels of
enjoyment, from the moment of triumph when you finally crack the last letter on
the collar that had seemed half invisible and with a bewilderingly
shape-shifting ability, to the joy of seeing old friends again (corny, but
true). For me, though, it’s the stories that come from it that are amazing. Where
and when was the bird caught? Where else has it been seen before? And of course each
time that bird is re-sighted, the story grows. Has it paired up? Did it have
young this year? All this data is invaluable to researchers, but it is also
unbelievably satisfying and fascinating personally. It connects you to that
animal in a very special way.
Not just geese! A colour ringed chough on Islay
So enough of all that emotional stuff. I would urge you
though, if you see a ringed bird, or any marked animal, take the time to try
and read its tag and just as importantly report it. The information is really
valued. For birds, a good starting point is the BTO website (http://www.bto.org/). For any of you
on, or due to visit, Islay there are any number of marked birds here. All the goose
species found here have marked birds, as are many of the choughs. waders are also often worth a good look. If anyone sees
any collared white-fronts.. I want to hear from you! Ed.Burrell@wwt.org.uk. I’ll try and
fill you in with some details of the bird where possible. Just as a teaser.. there are white-fronts on Islay at the moment caught on the island, elsewhere in Scotland, in Ireland and even Greenland; keep an eye out.
So there is my defence for my addiction to ring reading. Try
it, you might get hooked..
Caught as an adult (i.e. >2 years old) in Ireland in 2001, P3A hadn't been seen since 2007 until we met a couple of weeks ago on Islay. At least 14 years old and still going strong. A shoddy bit of photography on my part, but a good story.. It's what it's all about!
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