IBM Protocols:
Nest climbing and marking of
nestlings in the wild
1) Introduction:
When the first wild-born Bearded vulture hatched in 1997 in the Alps after 100
years of absence, leading experts in the ecology of the species met in Goldau
(Switzerland) to deliberate on some necessary rules together and decide the best
action plan regarding the management of the breeding in the wild to avert any
risk for the species. Among other solutions regarding the public awareness, the
most important decision was to avoid any kind of disturbance of the natural
development of nestlings born in the wild. Thus, everybody agreed not to take
blood samples for DNA analysis and DNA data bank, not to put rings or any
other marking pattern at the juvenile birds and not to approach the nest sites
before fledging.
In the meantime, after a period of 15 years, the new established Alpine
subpopulation has developed exceptionally: 14 offspring (at least!) fledged
successfully in 2011. Some of these nestlings come from pairs of second
generation already.
The monitoring activities (bleaching of feathers, coloured rings, network of
observers, radio tracking and DNA analysis) of vultures in the breeding stock
and the birds released since 1996 increased our possibilities to follow the birds
in the wild remarkably. Therefore within the Alpine in situ project we have the
unique possibility to study the development of a whole new established
subpopulation of Bearded vulture, its eventual connection to autochthonous
European subpopulations and to recognize possible threats as soon as possible.
Until now it was only possible to conduct DNA analyses from a very small part
of the offspring fledged in the wild by collecting feathers in the nests (after
fledging) or found by chance, but in the overall knowledge this was not such a
big problem as most of the birds came from the captive-breeding network.
However, since 2007 the number of birds born in the wild has exceeded the
number of released birds per year, and the estimation in 2011 is that ~38% of the
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total population is wild-born. There is therefore a lack of information regarding
this large part of the population. Furthermore Barbara Gautschi-Hefti and
Franziska Lörcher demonstrated in their genetic studies the potential loss of
variability of the Bearded vultures in the recent Alpine subpopulation, which
makes it even more important to follow up how the situation is in the wild.
2) New strategy
During the meeting of the IBM Steering Committee and the International
Bearded vulture Information meeting in Mallnitz (Austria, November 2011), and
the meeting of the VCF (Vulture Conservation Foundation) in Madrid (Spain,
December 2011), it was decided to modify the general trend and include the
birds born in the wild in some of the marking/sampling techniques when
possible. There are a few reasons why it became necessary now to do so; the
overall intention is to find a balance between the necessity to disturb as less as
ever possible at the nest site and the goal to collect data and increase our
knowledge with respect to this important fraction of the Alpine population.
Keeping in mind this prediction, the following questions should be answered in
the protocol:
a) Which marking patterns/samples are absolutely necessary?
b) At what age should the process be done?
c) Procedure of the nest-climbing
d) Should the climbing be avoided in some case?
e) Behaviour of the adults
a) Which marking patterns/samples are absolutely necessary?
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Fixation of colour rings: Yes. It shall be made according to the marking
pattern provided by the IBM Administration, different from the one used for
the released birds. The ringing of birds in the wild is subjected to the Euring
scheme, so this marking pattern shall be produced under the international
guidelines. The material of the ring has been traditionally aluminium. A
combination of a metal ring (officially from the EURING scheme) on one
leg and a PVC ring (Darvic) on the other leg should give most advantages as
possible. On one hand the metal ring doesn´t get lost (most probably) and
gives the chance for a clear identification of the bird if it is found dead or
recaptured. On the other hand the Darvic ring gives the possibility to identify
the bird in nature when the ring can be observed under optimal
circumstances or on a picture. The colour should be visible for a long time
(up to now experiences on Bearded Vultures are missing). Additional a clear
identification of the bird should be possible through the letters and/or
numbers given on the ring (like they are used for Griffon Vultures for years
already).
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Fixation of a radio transmitter: In principal no, but in special cases it
might be discussed (for example to compare the behaviour between
naturally- fledged offspring and released ones).
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DNA sampling: Yes, extremely important. For the chick this can be done
either by taking blood samples (only in case the collector is experienced
since there might be some complications) or plucking some feathers (trying
to take them whole with the root if possible). Besides, it is also very
important to collect any other feather from the nest that might belong to the
adult birds. In case there are rests, it might be of use to collect egg-shells.
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Wing tags: No, they are not used within the Alpine project because of
several reasons: disturbance of the bird, especially in flight, confusion when
wing tags get lost, etc.
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Bleaching of feathers: No. Although this might be very positive, it takes too
long to be done properly
The average time invested should not exceed 15 minutes (“safe time”). The
ringing of both legs and collection of samples for DNA analysis takes 5-10
minutes.
b) At what age should the process be done?
For security reasons any activity inside the nest with an offspring of
unknown age should be avoided. The best age for handling the chicks is when
they are between 2.5- and 3-months-old. During this life span there is no
serious risk that the young vulture might jump from the nest because of the
disturbance and that parents could abandon the nest since both leave their
offspring alone for hours, having though a good chance to avoid any negative
stress of the adults.
A special situation that might arise is the attachment of radio-transmitters, if it
is decided to use this method under special circumstances as mentioned above.
In this case the transmitter cannot be fixed at this age (between 2.5- and 3months-old), so the best option would be to try to catch the fledglings in the
surrounding of the nest site (if ever possible when the parents are absent) after
fledging when they are still not able to fly properly. Consequently it is necessary
either to know the time of hatching of the offspring or, in case it is possible to
have a clear look at the bird in the nest from a bigger distance, to estimate its age
accurately. This requires thus an intensive monitoring of the nest to be as
accurate as possible.
c) Procedure of the nest-climbing
Before undertaking any action, the IBM Administration should be informed.
The manipulation should be done by or under the guidance of an experienced
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rock climber (to avoid any unnecessary risks and realize the climbing as fast as
possible using professional equipment), together with a specialist accustomed
and experienced with the behaviour of Bearded vultures. It is also advisable
to count with a veterinary in the team that doesn’t have to climb to the nest
but should remain at close hand to act in case of emergency (e.g. there’s a
problem with the chick and this has to be removed from the nest). If possible the
team should not be larger (2 climbers and a veterinary close by). Any
accumulation of inquisitive people near the nest during this action should be
avoided. In some countries (for example Austria and France), besides the
required permits to climb the nest, it is necessary to ask for special permission
(Ministry of Science) when collecting blood samples, so please bear it in mind
beforehand to ask the appropriated authorizations.
Although it is specifically not advisable for the difficulties and risks for the
chick it implies, in case it is decided that the marking procedure is done by the
rock climber alone, he/she has to be trained carefully beforehand. It is especially
important to explain in detail how and where to put the rings on the chick, how
to take feathers and from which area and how to store them afterwards. It is not
recommended to take blood samples in this situation. Likewise, this person
should be prepared in advance for the possible reactions of the nestling, so it is
necessary to explain how to lay it at its backside, how to fix its body or legs and
how to react in the case of aggressions in order to save time in the nest.
The ideal would be to create an expert team to do this job for a longer time
and perhaps at several nest sites. Once you have the experience on how to
approach a certain nest site and knowing the possible reactions of Bearded
vulture nestlings, this work can be done more professionally and in a much
shorter time.
d) Should the climbing be avoided in some case?
It’s common sense that the climb should be avoided under unsuitable weather
conditions to avoid unnecessary risks both for humans and animals. Before
starting the climbing, the team should assess the situation and decide whether
the whole process of approaching the nest is too complicated to do it within a
safe time (see point 2.a), since otherwise it is better not to start.
It is very important to avoid the marking of offspring of a new pair breeding
for the first time. It is better not to disturb them in any way during the first
breeding attempt. Therefore, the marking of chicks in the nest is limited to pairs
that have reproduced successfully at least once in their history.
The process should not be started in case the age of the bird is unknown (see
point 2.b)
e) Behaviour of the adults
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So far, our experience regarding the behaviour of the adult returning to the nest
site during our activity at the nest is quite limited. To our knowledge no
aggressive behaviour has been observed in the Pyrenean population up to date
during the hundreds of nest visits by our Spanish colleagues. But in many cases
(such as captive-bred-and-released birds) the birds are more accustomed to
humans and every since in a while it has been observed within the breeding
network that some parents are defending their nestling violently. Nevertheless
the climbers should be prepared if an adult decides to attack. This is by no
means as dangerous as the violence shown by angry Golden eagles, but the
surprise can cause an accident both for the climbers and the chick. It might be
recommended to keep walkie-talkie connection with the third member of the
team (the veterinary) that acts thus as lookout and could inform in case of
parental approach.
The behaviour of an aggressive bird defending its nest is as follows: it tries to
grasp the intruder with both legs and to fix him, and then attacks with the
beak accompanied by powerful wing beats. This is not very painful or dangerous
but impressive, and it is really difficult to get free if the bird succeeds in
grasping an arm or leg. The talons are extremely strong and it is difficult to
release the grip if you are alone avoiding hurting the bird.
3) Acknowledgements:
This protocol was created by Dr. Hans Frey and edited and adjusted by the IBM
Administration in cooperation with some collaborators of the IBM and the VCF.
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