Blog #452 The Fledgling Fishermen
Like a child going to school for the first time, the young fledgling leaving the nest is exposed to a whole new world beyond their parent’s control. Ten-years of observations at the Salt Point nest (sample size = 29) reveal that maiden voyages, or first flights, are usually spontaneous events that occur when conditions are just right: a gust of wind lifts a fledgling frantically flapping and trying to get airborne. Fledglings on their first short flights show only modest control as they beat their wings continuously to stay afloat. Gaining altitude is as problematic as steering.
The fledglings usually stay proximate to the nest on first flights rarely flying higher than the trees as they circle the nest platform 2-3 times before their first landing. Several fledgling at Salt Point over the years have detoured to attempt landings on the snags before coming back to the nest but without success.
One thing is true of all fledglings, they make awkward first landings. Landing skills seem to be independent of other flight skills and are perfected at each individual’s pace. Every landing is fraught with issues: either the young birds approach the nest too steeply and too rapidly or they need altitude to reach the nest and barely make it to the nest. Landings are safest on the nest where there is room for miscalculations. Landing on branches takes additional skill and is easiest performed on the snags or branches in the open. Each year, there seems to be a class clown: a fledgling who keeps landing on branches that can’t support her and falling off, branch and all. When the fledglings get accustomed to flying they begin to fly from one perch to another, but the activity still centers around the nest. Landing in a tree with leaves takes added precision, but Lilly, easily negotiates it on her second day of flight.
After 3-7 days of flying around the nest the fledglings add gliding flight, interspersed with wing beats, to their routine. The young explore the area farther from the
nest: flights now include flying north over the lake at the North Cove and to the south along the near shore of Salmon Creek. Soon they will expand their flights east to the meadow and start flying in a wide loop around Salt Point.
These early gliding flights, interspersed with wing beating, can be clumsy, especially if the wind is strong; the fledglings learn the nuances of flight.
One pattern is clear: the skills of the fledglings keep improving with age. As a fledgling becomes more practiced, its flights become more elaborate, longer in duration, and more frequent as they expand the area they explore.
The last ten days of relentless rolling thunderstorms has hampered the progression of the fledglings flight, but they will make it up as soon as the weather
clears. Orpheus and Ursula sheltered in the cottonwoods during the storms as did LiIly. After Milly and Silly fledged on July 14th, the former in the morning and the later in the afternoon, they joined their family resting in the trees. Sheltered from the rain, the Ospreys have little to do except to preen and sleep.
The Osprey nest may look empty now, but it is still the site of regular family meals and lots of commotion. The fledglings still use it to nap, although the trees are preferable. In between bouts of play and fishing practice the fledglings can be found on nearby snags and open branches.
It is impressive that Orpheus was able to feed his family despite the sediment laden floodwaters of the last few days. Flooding resulted in high water everywhere, Salmon Creek overflowing its boundaries, and the lake level rising. In the aftermath, the calm, glass-like lake is good for plucking fish near the surface.
The post-fledging dependence period varies: the average is 30 days. At Salt Point it is often a few days longer. This year the fledglings have a head start, having fledged early in the season, and have all the time the need to practice. Every year, Orpheus has fed his offspring until the day they migrate, usually in mid-September. Even when a juvenile Osprey is capable of fishing for itself, it will still take its father’s free meals at the nest. Orpheus and the other fathers continue to fish for their young at about the same rate as before fledging throughout much of the post-fledging dependence period regardless of its duration.
Young fledglings play with objects, chase siblings and other birds, and learn to fish. Flying after siblings and playing tag is a popular sport among young Ospreys worldwide, as well as hounding other birds such as crows, gulls, great blue herons, kestrels, Merlins, and peregrine falcons for the fun of it. Attacking an eagle in jest could be a deadly mistake. Fledglings often play with and manipulating clumps of moss, algae strands, sticks, and twigs beginning on their fourth day post-fledging, and taking them to the nest. They seem keen on rearranging the nest interior and do so for many days, but they don’t really contribute to the nest maintenance. The Salt Point fledglings have been fussing with their nest during breaks in the rain, repositioning sticks and moving nest contents around, but when it is really pounding rain, they hide in the trees and doze.
Whether in New England, Montana, or at Salt Point in Lansing, fledglings have similar reactions to intruders flying by the nest. At first, the young spread their wings, protectively mantling the nest and giving alarm calls. As they get older, they joined the parents in pursuing strangers and sometimes give chase themselves. Some intruders are only yelled at but not chased: Are they familiar neighbors? Fledglings are also known to beg food from nest intruders and beg food at neighboring nests. The full roll of intruders in the Osprey society is still being elucidated.
Orpheus’ role as the adult male keeps changing throughout the breeding period. During the nestling and fledging phases, Orpheus gives fish to Ursula to feed to the young, but during the post-fledging phase, both Orpheus and Ursula hunt and leave whole or partially consumed fish in the nest for the young to divide.
Starting on fledge day, the fledglings now settle food disputes by stealing the fish off to a perch to eat. Those still nest bound can only complain. Once the others fledge, the young may move a fish from perch to perch as it is chased by a sibling. Unfortunately, these chases often end in the fish being dropped and not recovered. Nestmates fighting over fish is commonplace and increases in intensity over time until the birds start fishing
for themselves. Often the eldest, most developed and aggressive fledgling steals the fish. Perhaps this motivates the younger siblings to become independent.
Eyes to the sky! Candace
Candace E. Cornell
Friends of Salt Point Lansing, NY
Cayuga Lake Osprey Network
cec222@gmail.com
Comments
Post a Comment