On Osprey Time

Eyes of a domestic cat (Pinterest) and Osprey (Osprey Tales), lion (istock) and  goat (Pinterest), human (B.Martell), and gecko (Fineart America). THE PREY Big-horned sheep and white-tailed deer, courtesy of flicker. Grazing prey animals have horizontally elongated pupils and laterally placed eyes. Horizontally slit pupils have an expanded field of view because more light is let in from the front, back, and sides. The orientation also helps limit the amount of dazzling light from the sun so the animal can see the ground better. The animal can rotate so that its pupils are aligned with the ground whether its head is upright or looking down. Grazing animals’ eyes can rotate by 50 degrees or more in each eye, a range 10 times greater than human eyes . Horizontally elongated pupils create sharp images of horizontal contours ahead and behind, creating a horizontally panoramic view essential for detecting predators from various directions. Once a predator is detected, the animal needs t...

Orpheus skims the water for a drink and to wash, courtesy of Cynthia Sedlacek. At five weeks old, the Salt Point Three have finished their exponential growth spurts and are putting on muscles and their final feathers. Despite their new ability to thermoregulate, the nestlings still lounge in the shade provided by Ursula as their “mombrella.” The nestlings’ tender skin is sensitive to UV rays exposure, and Ursula does her best to keep them cool in the hot summer sun. Ursula will take quick dips in the creek or lake to further cool off the young. Ospreys get their drinking water from the fish they eat although, once they can fly, they may sip water from the lake or creek. The young birds have fully developed crops now, which are the first chambers of their two-section stomach, where food is digested. When satiated, the crop will bulge. From their second-week-old onward, feathers start replacing down. First to grow are the rusty-yellow pinfeathers on the head and neck followed by dark bod...

Four-and-a-half-week-old chicks with rusty-golden feathers around their neck, courtesy of Andy Morffew. Ursula’s and Orpheus’s nestlings are in their fourth week of life and are looking more and more like their parents as their feathers grow in. At 2 weeks of age, their first feathers start replacing the down with golden-rusty feathers around the head and neck. Darker body feathers follow. By 20–25 days, the nestlings’ primaries, secondaries, and rectrices (outer feathers of the wing and tail) have grown in—and they itch. Finally, the flight feathers grow in on the wings and tail. These are the longest feathers and take time to grow. Once these are formed, the fledgling is ready to fly! During the period of rapid growth between 15–30 days, chicks were gaining up to 0.1 pounds a day (about 2–3% of their final weight). After 30 days, they are 70–80% of their adult size, and their period of rapid growth has slowed. The males' growth is almost complete, but from day 30–35 females will ...

  On Osprey Time On Osprey Time just moved to blogger.com. Pardon the delay in posting.  Please bookmark! A mother feeding her 3.5-week-old offspring, courtesy of Cynthia Sedlacek.   Three and a half weeks into the nestling period, the three chicks have grown halfway to their adult size with Moana, the eldest, weighing just shy of a pound. Full-grown adult males usually weigh 2 pounds and females can be up to 4.4 pounds. Sleeping through most of the day and all night, the pile of offspring springs to life whenever their father, Orpheus, brings a fish to the nest. When awake, the nestlings waddle around the nest with their enormous feet, defecating over the nest edge, and peering over the rim at the people below. They are starting to use their wings for balance and rock forward on them to get a good stretch. When it’s mealtime, the eager chicks make their way across the nest to get fed by their mother Ursula.   Once their crops (storage organs; see second photo below...