Blog #331 Flying fishermen

Ospreys, consummate flying fishermen, are well adapted to succeed as apex predators of Cayuga Lake. One look at Orpheus hunting and you see he was designed for the job. 

Osprey fishing, courtesy of Kristofer Rowe. 

Orpheus’s long muscular legs enable them to stretch below the water’s surface to grab  the fish he spotted from a hundred feet above the water. His powerful leg muscles help  hold the struggling fish as he suspends it mid-air in a head-first aerodynamic position on  his return to the nest. 

Plunging into the water, courtesy of Jeff Wendorff. 

The dive itself requires absolute accuracy, first in spotting a fish and then plunging to its  exact location. Just before contact with the water’s surface, he extends his legs  

The Osprey’s feet are perfectly adapted for fishing, courtesy of Peter J. Markham.

stabbing the fish. Amazingly keen eyesight and wing maneuverability are needed to  guarantee ensures a kill. Orpheus’s sharp, curved talons pierce the sides of the fish,  while spiney bumped skin on the underside of their feet and lower legs called ‘spicules’  prevent the fish from slipping away. 

Once the fish has been pierced, the grip is secured further with the use of reversible or  “zygodactyl” outer toes, which swing around to join the rear toe on each foot. These  paired toes give greater control in grasping and maintaining hold on the prey, an  adaptation also found in owls and woodpeckers. 

Ospreys can only dive to a depth of three feet due to his bouncy. Ospreys coat their  feathers with waterproofing uropygial oil, which keeps the feathers from getting soaking  wet by creating minute pockets of air around the feathers. This trapped air acts like  pontoons, making the bird buoyant.  

How does the Osprey take off from the water with a 5 lb. fish in tow? Having feathers  that don’t get soaked is important. It’s powerful nearly six foot wingspan helps it regain  altitude, but lifting off with wet wings and a heavy fish demands a lot of effort. This will  be explored in more deeply in the next blog, #333.  

Half-open nictating membrane closes to act like goggles. Nares membranes close to form nose plugs.

Osprey feathers aren’t only special for their water repellent quality. The pale underside  of an adult Osprey’s plumage blends into the bright sky, making the bird hard to see by  prey. It’s also thought that the black ‘bandit’ eye mask might help reduce reflections on  the water. 

Ospreys commonly soar up to 150 feet above the water before hurdling Earthward at up  to 80 mph. At these altitudes, excellent vision is a must for being able to see a potential  catch. A high density of receptors in the eye enables powerful, clear vision. Their eyes  are adapted for a proficiency in hunting fish in another way, as they have a third  transparent eyelid—a nictating membrane—which acts as googles, protecting the eyes  upon impact with the water. They also have slanted nostrils with membranes that plug  their noses during a dive. 

These unique adaptions increase the Ospreys’ ability to hunt, which averages one catch  out of every 4 attempts. External factors such as high winds, poor visibility in heavy rain, or the size of the fish can pose challenges. Although their wings are mostly tucked in  when diving for a fish, wind can still catch them and push the bird slightly off course and  out of range of their meal. In addition, fish respond to predators by swimming deeper. If an Osprey catches a particularly large species like a pike (which can grow up to five feet  long), they may be unable to lift it from the water. 

Orpheus with a white sucker in route to the Salt Point nest.

During April and May, Orpheus averaged bringing only two medium-sized fish a day to  Ophelia due to the changeable weather. However, now that its June and the chicks  have hatched, these numbers just won’t cut it. With an additional three mouths to feed,  the number of fish delivered each day has more than doubled. Weather permitting,  Orpheus on a good day will bring 4–5 fish to the nest for Ophelia and the hatchlings. As  the chicks increase in size and appetite, Orpheus will have to work harder to sustain his  young family.  

While hunting adaptations give the Osprey maximum efficiency, they still have to  overcome the high energy demand of fishing. After Orpheus snags a fish, he usually  takes it to a perch to take first dibs on the most nutrient-rich part of the fish—the head. Orpheus gets all the protein and calories he needs from eating this small fraction of the  fish, leaving the bulk of the moisture filled body for Ophelia and his offspring. 

Eyes to the sky! 

Candace  

Candace E. Cornell  

Friends of Salt Point  

Cayuga Osprey Network 

Lansing, NY  

cec222@gmail.com 

EYES ON OSPREYS 

WATCH! 

Salt Point Osprey Nest Cam 2021 

READ! 

On Osprey Time—A Blog on the Ospreys of Salt Point

VISIT! 

Cayuga Lake Osprey Trail 

HELP PROTECT OSPREYS 

• AVOID GETTING TOO CLOSE TO NESTING SITES DURING THE BREEDING SEASON. IF AN ANIMAL  VOCALIZES WHEN YOU'RE NEAR, YOU ARE TOO CLOSE! BACK OFF IMMEDIATELY. 

• CARRY BINOCULARS TO VIEW WILDLIFE FROM AFAR. 

• RESTORE, CLEAN, AND PRESERVE LAKESHORE AND WETLAND HABITAT. • RECYCLE USED FISHING LINE, WHICH CAN BE HAZARDOUS TO OSPREY.  

• JOIN THE CAYUGA OSPREY NETWORK AND VOLUNTEER TO HELP MONITOR OSPREY NESTS. WRITE TO: CEC222@GMAIL.COM.

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