July
16, 2003 Commentary:
In late August or September our Osprey's will follow their instinct
to migrate southwards. Much has been learned recently about Osprey
migration through the use of Global Positioning System GPS) tracking
systems which allow researchers to see the migration routes of
individual Ospreys, and to see where they winter. The following
link has a variety of tracks from Ospreys that have migrated south
from Minnesota:
http://www.birdsofprey.org/migration.htm
and this link shows the southward migration tracks of Scottish
Ospreys:
http://www.ospreys.org.uk/AWOP/Satellite.htm
If you want to see Ospreys on their migration there are a number
of good places to go on Long Island. The best place is Fire Island
from mid-September until the end of October when a north or northwest
wind is blowing. North and northwest winds blow migrating birds
south; the birds don't like flying over water unless
they can see land in the direction of their destination. So, when
they reach Fire Island and they can only see the ocean to the
south, they fly west along the length of Fire Island until they
can see the New Jersey coastline. At Fire Island locations such
as Smith's Point, Old Inlet and Bellport Beach you can see several
dozen Ospreys migrate past on a good day. Other birds of prey
also use this route and it is not uncommon to see Northern Harrier,
Peregrine Falcon, Merlin, American Kestrels, Cooper's Hawk and
Sharp-shinned Hawk during the same north or northwest winds.
The Third
Chick:
Another key
factor in nestling competition and survival is the timing of egg
laying and egg hatching. In the case of our Ospreys, the third
nestling hatched a full three days later than the first two chicks.
Chicks grow very quickly, and the third hatchling was already
at a distinct disadvantage when it hatched because its siblings
had been eating voraciously and growing for three days. If it
had hatched one day later than the first and second chicks, it
would have been closer in size to its siblings and better able
to defend itself and compete for food.
Frequently
Asked Questions about Ospreys
Q. "What
is the purple thing in the nest that seems to be stuck to one
of the ospreys?"
A.
I believe that it is a piece of plastic.
As to nesting material, it's mostly sticks (never seen them collect
bark), the center or "bowl" is lined mostly with material
from the tide wrack, i.e. sea grasses, flotsam and all matter
of floating garbage; they seem to be particularly fond of black
plastic bags. I had a nest on Gardiners that I dubbed the Blue
Room due to the occupants propensity to incorporate a wide assortment
of blue and green plastic rope, bags, beach toys, etc., etc. into
the nest.
-- Wiildlife
biologist Mike Scheibel
Timeline
July 14,
the chicks are practicing flapping and hopping for much longer
periods. Early in the morning, the chicks took turns exercising
their wings. The larger chick actually flew up out of the camera
view for a
few seconds. Even the other chick was impressed as it watched!
July 14,
15:43 (3:43 PM), Adult brings a small fish and as soon as
it landed in the nest the smaller chick lunged and grabbed it.
The adult then took off leaving the larger chick screeching and
circling around the nest. The smaller chick kept its head down
and ate the whole meal in about 8 minutes.
The larger chick kept circling and flapping its wings in protest,
and even lunged at the smaller chick, but it didn't get the prize.
Even after the fish was gone, it continued to scold and threaten.
Finally, after 3 or
4 minutes, the larger chick decided to exercise its wings on the
edge of the nest and quiet down.
July 15,
12:36 PM, both the chicks are lying motionless next to the
grass.
The hen is sitting on the perch and calling. The hen then circles
the nest, lands and becomes very agitated, screeching and holding
her wings out. Suddenly a shadow flies in from the north and the
hen crouches down and then flips over exposing her talons upward.
As the attacker flies by she flips back on her feet and watches
the other bird as it flies away. The attacker makes several more
passes and the hen leaps up at it. On the final pass, the hen
leaps up and flies off. During the entire incident and for the
next 30 minutes or so, the chicks don't move or make any sounds.
At 14:00 (2:00 PM) the 2 chicks and the hen are all moving about
the nest as usual.
July 16,
6:00 AM, first chick leaves the nest. An adult was on the
perch and the chicks were calling to it. The adult left and the
smaller (# 2) chick started doing exercise lift offs. After several
lift offs it went up
and to its right (west) and disappeared.
July 16,
13:19 (1:19 PM), second chick leaves the nest. Both
chicks were in the nest, the larger (#1) was exercising and pacing
about the nest, the other (#2) was lying down behind the grass.
#1 took off for the perch but misses, (you can hear it hit the
perch). The other chick sits up and watches as #1 circles above
and around the nest. #1 finally succeeds in landing on the perch
and #2 appears to call out in approval, then does a little victory
dance. The two call back and forth as #1 sits on the perch.
July 17,
the first full day after both fledglings have taken to the air.
They have taken turns flying off, # 2 more than # 1, but return
to the nest to be fed and rest. The adults bring small fish that
are taken by one
or the other fledgling, but neither will share.
July 18,
the hen and the young continue to return to the nest to feed.
The competition for the fish the male delivers is fierce and sometimes
violent as the young birds and the hen all go for it. The young
then try to
steal the fish away from each other.
Visit our Ospreycam any time and this webpage again for
an updated commentary for the week.
