BANDING, FOR THE BIRDS OR JUST FOR THE
SCIENTISTS?
Dear Marilyn
Your recent mails are in reality about 'the good of science', although
in
the case of banding birds science has been helped by a large group of
enthousiasts, for whom the thrill was mostly in the banding activities
themselves (No doubt sublimated hunting) and partly in the close-up
contacts and handling of the birds; I have a friend in the US who every
time she has a chance to take part in banding activities, is completely
enraptured by the feeling of keeping these live birds in her hands prior to
releasing them. Let me also add that I am not a bander myself, and have
never been one, but as a museums curator, I mediate a lot of returns of
bird bands to the banding central in Stavanger, and inform the finders of
what their assistance in returning the band helps achieve.
Increasingly, banding in most countries, and I have no doubt also in
Australia, is more and more regulated in that would-be banders need a
permission (and here in Norway also must pass a test, before obtaining such
permission), and the banding itself has developed from the almost random
banding of all the birds one could get hold of, into a much more
'scientific' activity, where banding is used in order to obtain answers to
specific well-defined questions. The earlier random banding has been very
useful in many respects, as it helped answer questions such as: Where do
our birds go in winter? How long do they live?, or What are the most common
causes of death? (And by the way, such studies compared with other methods
have also taught us that banded birds live just as long as unbanded
ones, on the average, so that contrary to accusations that surface
regularly also on Birding-Aus, banding is not a statistically important
cause of death for birds. That is not to say, that no birds get killed
during banding, or suffer after-effects from improperly placed bands; such
things do occur.)
You ask if banding benefits the birds banded. Of course it does not, in
any direct way. For the great majority of banded birds neither the banding
process or the presence of the band in the years ahead makes any difference
at all, but any effects that there might be, are bound to be negative. So
is it still worth it for the birds, or is this only something that
satisfies the academic interest of some scientists? This has to be decided
for every case, weighing the negative effects of your interference with the
birds against the positive effects of the results obtained by this
interference.
Before talking about cannon netting, I'll give you a much starker
example.
North of here, in the estuary of the river Tana in Finnmark, in late summer
many thousands of Common Mergansers (Goosanders) Mergus merganser
congregate for moulting. Banding returns, and some other evidence, show
that a large part of NW Europe's mergansers come to this area for moulting
on the extensive sand banks off the river mouth. Now the Tana river is also
one of the prime salmon rivers in Norway, and as everywhere in this country
, the salmon population is decreasing. The finger was i.a. pointed at the
mergansers (unfortunately called Laksand (=salmon duck) in Norwegian), and
there was great pressure to allow shooting the ducks 'in order to save the
salmon'.
I put a student on the problem, but we did not succeed in finding a
method
of catching the flightless, but still extremely flighty mergansers loafing
on these off-shore sand-banks. So I reluctantly decided and applied for
permission to shoot 150 mergansers, and this duly was done (A mortality
much greater than ever occurring in banding operations). The stomach
analyses showed convincingly that, although the ducks did forage on salmon
smolts to a certain extent, three quarters of the catch were sand-eels
Ammodytes sp, a non-commercial fish, and on publishing this result the
pressure was off, and the mergansers are still protected in the area.
Here the morals are clear, in my opinion.The mergansers that were shot,
and no doubt a number that were wounded and not recovered, suffered dearly,
but the result of the exercise were of such benefit to the Tana mergansers,
that there is no doubt in my mind that in this case we did the right thing
in shooting a sample that was big enough to get statistically reliable
results that could convince all parties.
Birding-aus has had a long debate on another scientific programme where
birds were shot, i.e. the bowerbird case, and in that case the issues
involved were far more nebulous and the majority of the subscribers
concluded, I think still maybe a trifle glibly (But then , I am a scientist
of the typical 'on one hand..., but on the other hand....' type of endless
discussions and few decisions), that the shooting of the bowerbirds
was most unnecessary and very wrong. Every such case has to be judged on
its own merits, and most countries have developed some sort of
permit-approach, that allows such judgement to take place prior to
decisions on any such issue.
Cannon netting has primarily been developed for catching shorebirds (and
geese) that are difficult to catch by mistnets or other types of traps. I
have been administratively involved in only one such operation, many years
ago, when we wanted to catch a sufficient number of the Red Knots Calidris
canutus, that have a very important staging area in the Balsfjord close to
Tromsø; every May some 10 000 knots stay in this area for a few weeks and
fatten up (mainly eating the bivalve Macoma) in order to migrate on to the
breeding areas; at that time we did not even know whether we had Siberian
or Nearctic birds in rhe Balsfjord. We got a small grant, funnily enough
from NATO, and worked together with British, later also Dutch and German
colleagues; we succeeded, after much trial and error, to catch several
hundred Red Knots, and these were then subjected to various indignities:
banded, leg flags, full biometrics, weighing, blood samples, and in some
cases I think even stomach emetics to confirm our field data on what they
ate. I do not now remember what the mortality was during these catches, but
it was very low, and we only have a few birds in our collections that stem
from this work.
Clearly none of this benefited the flocks of knots that were caught, not
those that were harrassed in vain and that eluded the nets. But this work,
together with all the studies done elsewhere in the same years and later
on, gave a lot of very important results for science as well as for
conservation, the development of a network of protected areas along the
flyways of the Red Knot between the Arctic and in our case Africa; 'our'
knots were Nearctic birds flying on non-stop from the Wadden Sea in Germany
and Holland to N.Norway, and 3 weeks later from N.Norway to E. Greenland or
even Arctic Canada, they can not make this long and arduous journey without
the refueling and fattening staging-stop in the Balsfjord (and in
Porsangen, Finnmark). In addition, there were a lot of results of at first
sight purely scientific interest, having to do with the energetics of the
birds, and with the amount of genetic contacts between the different groups
of knots; also these results can later easily become important in the
efforts of keeping protected sufficient fueling stations for the birds
during their great yearly migrations.
In short, once more I am convinced that this cannon-netting was fully
warranted also from the point of view of nature conservation, even if the
science did interfere with the birds and possibly meant suffering and even
death for a limited number of the birds concerned. And once more each case
has to be judged on its own merits, although in the case of banding
research the sufferings and losses are so much less than during research
involving collection of birds, that the balance much more often will go in
the direction of that the results warrant the very small losses. Although
banding and cannon-betting of course never benefits the birds that are
directly hanging in the nets, the benefit for the populations or species
to which these birds belong are often clear and substantial, and banding in
its various forms has brought our understanding of our surroundings large
steps forward, in birds as it has in the case of fish, mammals, marine
invertebrates and insects.
Wim Vader,
Tromsø Museum
9037 Tromsø,
Norway
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