As part of
a study of the Crescent Island Pelican rookery, (1), eighteen juvenile Pelicans
from the Eastern rookery have been fitted with a metal band on the right leg
and a red plastic band with white numbers on the left leg. The bands are
required to track individual young birds to see where they disperse to and how
long they live.
In addition,
blood and DNA samples were taken from the juveniles when in hand for banding to
assess the health of the birds and their genetic relationship with the broader
Pelican population across the Gippsland Lakes and beyond.
Please click on photos
to enlarge.
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| Banded Pelicans 207 and 211 – also note the metal bands on the right leg. |
The
juveniles with bands are being tracked as they disperse from the rookery (they
are no longer using the rookery) to see how they disperse and to monitor their
survival as they learn to fend for themselves and become less reliant on their
parents feeding them over time.
Thus, over
the past few weeks we have been looking for the juveniles with bands and using
photos to identify and record the band numbers of individual birds. So far on
each weekly monitoring trip we have been able to find 9 of the banded young birds
which have not ranged much further than 1 to 2 kilometres from the rookery. The
young birds are all capable fliers and some may have dispersed much further
across the Gippsland Lakes by now. The juveniles are still being fed occasionally
by their parents.
To photograph
banded juveniles, they must be found standing out of the water so the bands are
visible. The birds regularly rest on sandy beaches and spits however on
approach the wary birds will often launch into the water. Some birds will be sitting,
often asleep, so we must wait for them to stand up to reveal if they have bands
and give us an opportunity to capture a photo record. A long telephoto lens is
needed so band details can be captured at a distance – too close and the birds
enter the water or fly off.
While
photographing banded juveniles recently a few of the juveniles were sleeping
among a group of young and some adult birds.
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| Group of juvenile Pelicans with some banded young. |
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| Sleeping juvenile – does it have a band? |
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| The sleeping juvenile awoke and immediately leapt to its feet and embarked on a prolonged rampage through the group. |
The young
bird charged at the others with wings held open and wide and the bill open. At
first I wondered what this behaviour meant. It was reminiscent of how the
juveniles behave after a prolonged feed with their bill deep in their parent’s
throat. Oxygen deprivation is thought to explain the seemingly drunken
behaviour which I have covered in an earlier post here: http://avithera.blogspot.com/2018/01/australian-pelican-juveniles-strange.html
It soon
became apparent the young bird was hungry and looking for a feed. There were
some adult birds present however it is unlikely that any of these were its
parents – they certainly were not offering a feed. The young bird did charge at
one adult bird in particular, a small female which may have been its parent,
however it also charged at juvenile birds. By charging and harassing the other juvenile
birds it might have hoped to get them to regurgitate some food, though this is
only speculation as I have not seen this happen before.
The following
photos show the young bird as it charged at the other Pelicans, both adults and
juveniles.
The rampage
went on for about one and half minutes until eventually the young bird ran out
of steam. This behaviour may achieve a food reward at times however it is
probably mostly a counterproductive waste of energy.
The following
photo shows an advanced juvenile being fed by a parent a week after the rampage
sequence was photographed so the young are still dependent on their parents at
this stage.
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| Advanced juvenile being fed by parent. |
The
juveniles are on the cusp of independence however their survival depends on
them being able to find their own food – many young birds do not make it
through this critical development phase especially in poor seasons when food
resources are scarce. Hopefully all the banded Pelicans will survive to become long-lived
adults however the odds are against them all making it.
Notes
(1)
This is a BirdLife Australia project managed by Deb
Sullivan and funded under the Gippsland Lakes Consultative Committee. Licensing
is through the Australian Animal Ethics and Departmental licensing.
