Volume 2 Issue 10
July 7, 2022
Pam Narney pnarney@gmail.com
When Osprey chicks are about 55 days old their final transition occurs. Flight!
They have gone from egg to adult in seven weeks.
Osprey watchers live on a roller coaster ride of emotions, exhilarating and frightening. Will they see a miracle or a disaster? One wrong gust of wind too soon, and a chick could land in the water. Part of the miracle is that this doesn’t happen often.
For these 55+ days the Osprey chick’s world was the confining and restrictive existence of life on an approximately two-to-six-foot diameter box. Given the opportunities for disaster, how do they manage to strengthen their wing muscles and fly?
Preparing for Flight
Local Colonial Beach Osprey should be showing the signs of leaving the earth and taking to the air: wing flapping, hopping with wing flapping, and hovering. The chicks are exercising and strengthening their wings. Flight feathers develop last and need exercising.
Wings Erect
As wing strength increases, the chicks no longer drag their wings but hold them close to their bodies as their parents do. I thought the runts dragged their wings because of the bullying, but this posture is natural part of their development.
The wing span of a nestling is now the same length as Mom's, about six feet.
Feet Are Flat
Feet and talons have developed for fishing and perching.
Control
The chicks must be amazed to notice long, difficult to control limbs at their sides. Imagine waking up one day to find that your arms morphed into randomly moving appendages with a six foot wing span, occasionally lifting you off your feet. Amazing or terrifying? What do the Osprey think?
The first time I saw a chick fly I expected the earth to move, but the Osprey looked like she had been flying for years.
A Crowded Nest
When one chick flaps the others follow along quickly until the nest is a dangerous place to be. This extreme and violent movement smashes the nest. Sticks drop off and footing is insecure. Someone could get whacked and fall out of the nest prematurely. Even though the nest is basically flat now, it hasn’t gotten any larger.
Chicks Are Left
Mom is off the nest more than on it, only returning to chase predators or to feed.
A Close Call
Carl slipped; his outside talon fell off the side of the nest. I held my breath. Fortunately, the other talon was anchored. He pulled himself back into the nest. The first flight is often accidental (Poole).
Pun intended. The first flight could be an accident. The first launch is precarious and often depends on blind luck. Everyone in nest faces the same direction. Into the wind. For lift. Facing with the wind pushing behind you could mean a quick fall into the bay and a quick death. Air flowing toward the chicks goes under their wings and helps them get up into the air.
“Think of air as a fluid. Yes, do. Then imagine this fluid streaming over aerodynamic wings, exerting pressure both upward and down. When the pressure above the wings is less than that below, the wings are ‘sucked’ upward; when the pressure is increased, the wings are lifted” (Gessner).
Fish Delivery Declines
“There is a curious drop in the number of fish delivered to nests just before the young fledge (age 40-55 days) and a rise about 15 days after that” (Poole 1989). Maybe the decrease in food stimulates a need to fly and feed themselves.
Gracie has been flying by the nest all day with one small fish taunting the kids. Come and get it!
Adaptations
Every part of a bird is light. The bones in their skeletons are hollow.
Their bodies are streamlined and strong. “The legs can be retracted into the plumage, or stretched out horizontally. The head, neck, and body are shaped to part air and ensure a smooth airflow” (Dorst).
Cassidy has been hopping along, flapping, hop flapping, and jumping.
Carl has extended and flapped his wings, but is lying low in the nest. How long will it take both of them to fly?
Watching expectantly is both stressful and joyful. Witnessing that moment of first flight, to humans, is witnessing a miracle. What is the Osprey experiencing? Freedom?
Can we even imagine what flying free, using only our bodies, would feel like?
First Solo Flight
Any second now!
Soon the skies above Colonial Beach will be crowded with Ospreys.
See last year’s blog for more pictures on flight.
Sources
Dorst, Jean. The Life of Birds. Vol. I. New York: Columbia University Press, 1974.
Gessner, David. Return of The Osprey. ISBN 978-0-345-45016-6.
Poole, Alan F. (1989). Ospreys: A Natural and Unnatural History. ISBN 0 521.