July
19, 2003 Commentary:
The timeline notes: 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.
Commentary:
This was obviously
an attack or at least aggressive behavior by another bird. But what
kind of bird could attack a full grown Osprey? In his excellent
book “Ospreys, A Natural and Unnatural History” Alan Poole writes
that he found seven Osprey carcasses, all of which were incubating
females, were found with puncture wounds from talons in their bodies.
All of the seven dead Ospreys had been partially eaten. Dr. Poole
attributed the attacks to Great Horned Owls which nested nearby.
Great Horned Owls are very large, and are adapted to taking large
prey. An Osprey sitting on a nest at night would be a tempting target.
However, the fact that the attack at our nest was recorded in the
middle of the day would seem to indicate that it was a diurnal bird,
not a nocturnal hunter like a Great Horned Owl. It is possible that
an eagle would attack young Ospreys. It is also likely that an adult
Osprey would be able to fend an eagle off. Another possibility would
be an attack by a young inexperienced buteo such as a Red-tailed
Hawk. Red-tailed Hawks are large and are fairly common on Long Island.
A hungry inexperienced young Red-tailed Hawk might have overflown
the nest a few times in the hopes of an easy meal. If that was the
case for our nest, the young Red-tailed Hawk has now learned a new
lesson –mother Ospreys will defend their young vigorously!
July 16, 6:00 AM, first chick leaves the nest, July 16, 13:19 (1:19
PM), second chick leaves the nest. The fledging of both young on
July 16 was very exciting news. No longer bound to the earth the
Ospreys we have been watching for months have now flown from the
nest. Fledging refers to a bird’s first flight. Our birds are no
longer nestlings; they have fledged and are now post-fledglings.
This is a critical time period for them. No longer will they have
to wait for their parents to come back to the nest with food. Now
they will need to learn to hunt on their own, and to catch enough
food to grow and to be able to undertake their long southward migration.
Fledged young vary widely in how fast they become independent. Typically
they are dependent on their parents for 10-20 days from fledging.
It has been reported that some Ospreys catch fish within three days
of leaving the nest. It has also been demonstrated that Ospreys,
which have been raised by humans quickly, learn how to catch fish
on their own, even though they have no parents to teach them. The
young Ospreys will likely stay around as long as their parents are
in the area. In that time they may visit other Osprey nests and
beg for food. It is not uncommon for adult Ospreys to feed unrelated
young – apparently they are unable to distinguish between their
own young and a stranger. When the adults leave on their southward
migration in late August or early September the young may stay near
the nest for a few more days, but will more likely leave at the
same time as their parents.
Frequently
Asked Questions about Ospreys
Q. "Would
the DPOF consider putting a transmitter on one of our ospreys?
What a great way for all of us to keep track and keep in touch
with 'our Ospreys.'"
A. This
is a good question that I do not think has been considered by the
DPOF. Our goal at the DPOF was to create a webcam and to watch “our”
Ospreys through their nesting season. It would really be exciting
to track one of “our” Ospreys via satellite. That being said, Ospreys
are protected and permits, including a valid research proposal,
would be needed in order to place a satellite transmitter on one
of our birds. We will keep this question in mind and see if any
of our members are engaged in research that would be enhanced by
the type of data that satellite tracking an Osprey from this area
would generate. In all likelihood, if this were to happen, it would
be in a future nesting season, not the 2003 season. It is a great
suggestion and an interesting project to contemplate.
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.
Week ending
July 26, the chicks are spending time away from the nest but
return for feedings. The adults will bring a fish and leave it
for the young birds, who then compete for it. Usually one or the
other will get the meal and finish it without the other getting
any, but they both seem to get their share over the course of
the day. All four birds spend the night out of the nest.
Visit our Ospreycam any time and this webpage again for
an updated commentary for the week.