Assuming the phalaropes were actually caught and flagged, in my opinion it
was a poorly made decision on the banders' part to leg-flag this species as
one of the feeding methods they employ is to spin around in a circle while
floating on the water's surface. In this situation a flag would obviously
cause extra drag on one of the bird's legs which may impair its ability to
forage efficiently (unless it can learn to correct for the extra drag).
Foraging efficiently can obviously have an impact on survival during
migration as enough reserves need to be accumulated to complete the journey,
it may be that only a small reduction in foraging efficiency is enough to
significantly reduce the bird's ability to accumilate sufficient bodily
reserves to see it through migration etc (but again we don't know this for
sure! in fact we know very little for sure but my personal view is to ere on
the side of caution) - if marking these birds, to be observed presumably in
their breeding grounds to know where they come from (as they are seen rarely
here) was necessary then colour-bands may have been a better alternative.
In fact colour-bands may be a better alternative for all waders as it is the
flag 'attached' to the band that seems most likely to be causing the
discomfort observed in some small waders - I have seen this discomfort
personally (with Red-Necked Stints including birds limping, favouring their
unflagged (metal-banded) leg, not using their flagged leg at all and hopping
instead) and also examined birds carrying flags in the hand to verify that
the band does not move as freely along the leg as a normal band as it is
weighted at one end.
As for leg flagging waders in general: I hate to dwell but would like to add
that based on the repeated observations of a number of people of small
waders experiencing discomfort or some sort of problem with leg flags (even
if some are false - I have seen it myself) I would like to see a review of
the practice to properly investigate this issue (particularly leg-flagging
versus normal colour-banding if the issue is the flag, which is something
that needs to be resolved, I am not arguing here that there is no merit in
marking the birds - if people are going to respond to this message PLEASE
stay within the context of what I am actually saying - no reading between
the lines!).
It is in the best interests of the birds but equally important the best
interests of the scientists to review leg-flagging, as the methods that are
employed to research the behaviour of animals should have the least impact
on the behaviour of the research subjects as any impact a method has on the
subject can be a confounding factor in the research and may lead to a less
than ideal picture of what the birds are actually doing. For example if
marking methods do indeed reduce survival then any study examining survival
as a demographic parameter will have results skewed by the research method.
To take another example, to look at weight loss during incubation the number
of times the bird is removed from the nest and weighed may increase the
weight lost by those birds compared to undisturbed birds as the activity and
stress levels of the handled birds are greater, hence the research would
give figures that are above average for the species. This applies to
basically everything that somebody studies (including observational work
where a human observer is watching birds), so scientists should (and many
do) validate their research methods to make sure they are not confounding
their results - I think there is sufficient anecdotal evidence to warrant
this for leg flagging, because if there are injury/mortality issues they
apply equally to the welfare of the birds as they do to the integrity of the
research.
For those who seem to want to defend banding without at least objectively
thinking about things first, well before you blast me as a Bennet & co - I
am a bander, but I like to at least try to view things objectively and as a
bander am concerned about the welfare of the birds that are being banded,
especially the ones I band.
Cheers, Dean Portelli
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