August
4 , 2003 Commentary:
This weeks summary has three parts; 1. A summary
of activity at the nest by David Shore, 2. Answers to questions
that have not yet been responded to by our experts, and 3.
A return to Dennis and his love of ospreys now that the young
have fledged.
1. David Shore’s Summary:
The chicks
continue to spend a lot of time away from the nest but still return
for feedings. The young birds are much better at flying and landing,
even on the perch. Their adult colors are filling in and they
have lost most of their chick feathers.
2. Unanswered
questions:
Question:
If and when the two bigger chicks start to leave the nest and,
the third chick is still alive, could he recoup? Will the female
pay more attention to him/her?
Answer:
It probably depends on how weak or strong #3 is when the siblings
leave. The fledglings often return to the nest to be fed (they
seem to remember where they got easy meals). The fledglings still
need to be fed even if they perch away from the nest, as it takes
4-8 weeks after fledging before they are successful at fishing.
But we have seen all 3 chicks survive, so it is possible that
the third chick gets more food when there is less competition
at the nest.
Question: Does the male actually withhold food so that the
weaker chick would be "picked on" even more, as a part
of survival of the fittest?
Answer:
I think the male is programmed to bring fish when he hears
the calling of his mate and later, the calling of the chicks.
We were told by the biologists here, that the adult birds withhold
food when it's time for the juveniles to fledge...part of conditioning
(lighter weight) for their first flight.
So in the hacking project, we cut back slightly on food when we
estimated it was time for our chicks to fledge. None of our chicks
(we averaged about 13 chicks each summer) during the 3 summers
we were involved with the project was ever left behind. One was
very late in leaving, but she finally took the risk in August
about 2-3 weeks after the others. An interesting note: on some
of the first flights, some of the chicks weren't sure how to fly
back to the hacking tower. We observed other adults in the area
(not related to these chicks) feeding them on their perches in
an old tree about 50 yards from the tower.
Question: "Can osprey live 13-18 years of age? "
Answer:
A website posting last week gave evidence that an osprey had lived
25 years, the longest on record nearly a decade longer than the
previous 16 year old bird.
3. A Tribute to Dennis
Readers of this website know that the motivation to put the camera
on an osprey nest and run the images to the web came as a tribute
to Dennis Puleston and his love for the osprey.
Born in England, at Leigh-on-Sea, on the north shore of the River
Thames, Dennis grew up in the words of a famous author, ‘messing
about in boats.’ It is unlikely in all that time on the water
that Dennis ever saw an osprey. When he came to the United States
he discovered them in numbers and they became one of his most
often painted birds. He, to his continual delight, studied the
ospreys on Gardiners Island, maybe the densest colony of colonial
nesting raptors in the world.
The fecundity of Gardiners Island ospreys would not last as the
use of DDT and its effect on top predators spread following World
War II. Dennis played a pivotal role in the banning of DDT in
1972 through his Chairmanship of Environmental Defense (then EDF)
from 1967-1972. Fortunately, he lived long enough to witness the
recovery of ospreys on Long Island and elsewhere.
It is fitting then to comment on the recovery of ospreys in Dennis’
homeland for there is a success story there as well. Ospreys had
been common in Scotland and probably England. They were even mentioned
in Shakespeare and numerous poets in the sixteenth and seventeenth
centuries. Subsequent persecution by those who viewed ospreys
as ‘varmits’ and by egg collectors, a peculiarly British
pastime, reduced their numbers. By the 1830s they were gone as
a nesting bird from England; in more remote Scotland, they lasted
until 1916.
Not surprisingly, it was in Scotland where they first returned
in 1954 to Loch Garten. When I visited this nest in 1962, there
were sentinels watching the nest around the clock. The base of
the dead tree supporting the nest was surrounded with barbed wire
to discourage egg poachers. Despite these efforts a person that
year was caught at the base of the tree with box containing the
eggs from the nest. Overcoming these setbacks, the ospreys in
Scotland flourished and now there are more than 130 nests scattered
around the country.
English ospreys required more time; ironically they nested for
the first time in more than a century and a half in the year that
Dennis died, 2001. Assisted by an artificial nest site built on
the shore of Bassenthwaite Lake in the Lake District, nesting
ospreys returned to England. For three years this nest has been
successful and has contributed to the tourism of the area. (Details
of these efforts can be seen on www.ospreywatch.co.uk.)
The "Return of the Osprey," the title of a PBS special
by Michael Male and the title of a book by David Gessner, has
been one of the conservation success stories on both sides of
the Atlantic. It is a story that is a theme of the life of Dennis
Puleston. It is a story that energizes his family and friends.
It is the reason we have had such a wonderful time this year observing
and not disturbing the natural life of a family of ospreys. And
it is why we have participated in this wonderful legacy left by
our friend and mentor, Dennis Puleston.
Visit our Ospreycam any time and this webpage again for
an updated commentary for the week.
