In order to be able to follow individuals
birds and their life history, they must be uniquely marked. This is a key component for the population
studies, and especially following the dispersal and survival of young birds.
Marking involves both SAFRING identification
rings and plastic CB rings, which with their bright contrast and large codes
allow much easier recognition and reporting of individual eagles in the field. The nestlings must be ringed within a
specific time frame; to be fully or near-fully grown to fit the ring well, but
not so mentally mature to think they could jump to escape this approaching
monster. Fortunately we were able to age
these birds well and time the climbs appropriately, ringing eight between
December and early January. Ringing juveniles and nestlings are particularly
valuable because we know their age and origin, and could provide some very
interesting longevity and dispersal data in the decades to come.
The behavior of the birds is very
interesting. I had expected more
aggression from the adults, such is the need for a riot helmet and foam filled
backpack. Fortunately all birds appeared
reluctant to attack. Two nests that I
have accessed have involved birds that were prepared to frighten me by a flyby
within about five meters.
The nestlings generally show a threat display as they first see me broach the edge of the nest, facing head on
with mouth agape and wings outstretched.
However as I climb further they may realize just how massively outsized I
am, and their next response is to go completely catatonic. This is very fortunate in that I can place a bag next to the bird and
simply lift it across, zip up, and lower it down. The young eagle is kept in the dark and hooded
while still in the bag. They generally
remain calm and docile while hooded, even during all the handling and
measurements.
Our procedure has been well practiced now, and although the time it takes to get a rope in a good position for access can vary greatly, the process of removing the chick from nest and back takes all of about 20-30 minutes - depending mostly on the height of the climb back to the nest.
*awaiting more photos of nestlings and nests*
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