an Osprey story

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Our trips to the river during the second week of March took on a new focus.  Based on my archive of photos, I determined that the female Osprey of the pair we watched the past two seasons would return to her nest on or about the 13th of the month.  The two nesting Osprey pairs to the north on the river had already made their appearance over the two previous weeks as anticipated. 

Right on cue, by the 14th, she was visible in last year's nest checking out any necessary repairs and need for reinforcement.  The male was also soon visible, both in the nest with her and soaring high over the tree tops, the two in tandem. 

The process of preparing the nest is a joint venture by both the male and female.  During this time "token" twigs are also brought to the nest as an offering and appear to be part of the bonding and mating process.  Most of the activity at this time is centered around the nest in preparation of the eggs that will soon be laid.

Typically, 3 eggs are laid with an incubation period of 32-43 days.  Both the male and female are dedicated to the incubation of the eggs with the female sitting most frequently and the male bringing her meals to the nest.  Quite often, the only thing visible in the nest at this stage is the top of the sitting parent's head.

 

During the infrequent times that the female leaves the nest, the male is close at hand to relieve her duties.  Her time away is usually short and upon her return there is a quick exhange of position while she settles back down in the nest.  As in most big birds, the female is larger than the male.  In the photo below, the female is the one flying back into the nest.  You can see how her tail feathers are a bit matted from her time on the eggs.

During the incubation period we try to limit our observations to brief drive-bys.  The Osprey pair, although dedicated, are easily disturbed and voice their agitation with a chorus of high pitched warning calls.  The first indication that the young have hatched is when the parent's position changes from inside the nest to a presence on the rim.  Their vigil remains the same as they protect the young from predators above.  Seldom is the nest ever left unattended.   

It is still a number of days before the chick(s) will become visible.  But what a glorious day it is when our suspicions of activity are finally confirmed.   The first sighting is usually just a curious head peeking above the rim of the nest.

The growth of young Osprey is fast and soon, not one, but  two chicks are visible with our sometimes daily check on the pair's progress.

As the young Osprey continue to grow, the nest soon becomes crowded.  The parents busy themselves with the chore of feeding two hungry mouths as the chicks are fast approaching the size of mature Osprey.  The young maintain their own vigil of the sky in anticipation of the next meal. 

Fish is the almost exclusive diet of the Osprey.  They are great fishers sometimes referred to as 'Fish Hawks'.   From a height of 100 feet or more they search for fish swimming near the surface.  When spotted, they dive headfirst towards the water throwing their taloned feet forward at the last moment before hitting the surface to grasp the fish.  The Osprey have unique feet with a reversible front toe as well as barbs, called spicules, which help them hold onto slippery fish. 

Once out of the water the Osprey stops to shake the water from its feathers and position the fish head forward to aid in wind resistance in flight.  It is then carried to a perch or directly into the nest for the young. 

From an early age the Osprey young are familar with the warning call of the parent.  In this video, the young chime in with the parent sounding their displeasure at my presence.  The higher pitched call is that of the chick. 

The young Osprey spend between 50-55 days maturing in the nest after hatch.  Prior to their fledge, they practice short bursts of catching air in their wings by hopping up into the air on the rim of the nest and flying the short distance across it.  When I know the time is near, I always hold my breath before we come in view of the nest wondering if this will be the day.  How exhilerating the freedom of flight must be to these juveniles who have spent so much time by now watching their parents wing in and out of the nest.  I came across the first fledge from this nest a short time after the maiden flight.  As it returned to the nest accompanied by the female parent, I could literally sense the excitement as it soared overhead.

It will be another 10 to 20 days before the new fledglings will be capable of  fishing on their own.  During this time the parents continue to bring fish to the nest for meals and maintain a watch of their activity from a visible distance.   

I'm not sure who was prouder of this fledgling as it sat finishing this catch--the parents or us.  It is common for the head of the fish to be eaten first.   Once the fledglings establish the fact that they can fish on their own it is time for the parents to migrate south.  The female is usually the first to leave.  The male departs later while the juveniles remain long enough to gather the necessary strength for the long flight south.  It will be three years  before a mate is chosen and the pair returns to the birth place of the male to begin their own nesting ritual. 

The Osprey, along with other large birds of prey suffered a significant decline  during the 1960s and 1970s.  Through the restriction of the use of DDT, we are witnessing magnificent comebacks in their populations. 

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