Blog #349 Ospreys in their Ecosystem

Olan flying over Salt Point Natural Area, courtesy of Karel and Cindy Sedlacek. 

Olan readily explores Salt Point and over the lake as he improves his flying skills. Initial  flights had signs of a tenuous pilot, but gained confidence is winning out. Rosie is being  

Rosie and Olan with Ophelia, courtesy of Karel and Cindy Sedlacek.

Rosie making an awkward landing at the nest. 

more tentative in her explorations, staying closer to the nest. It is such a thrill to see the  fledglings giving themselves over to the wind, trusting it to support them with a safe  invisible force.  

Rosie making another awkward landing at the nest, courtesy of Karel and Cindy Sedlacek.

Olan atop a branch above Salmon Creek, courtesy of Karel and Cindy Sedlacek. 

Later in the day Rosie joined Olan in his rounds flying the length of the peninsula and  back, playing follow the leader, Olan flew high up and Rosie tried to keep up with him.  Olan has mastered pumping his wings and gliding or soaring in between. Rosie has not  learned this coordinated flight yet. She has a very laborious flight, flapping continuously  and fighting for altitude. She flaps at least four times for Olan’s single flap. He flew in  wide graceful circles with Rosie literally on his tail. Back and forth in the sky, they flew  wherever the wind took them. One gust pushed them both backwards, a very odd sight,  and others pushed them sideways.  

At one point a third fledgling appeared from another nest and joined the game without  issue. That fledgling was able to catch up and tag Olan, so the two started their own  competition. Rosie tried to keep up, but soon returned to the nest. The two fledglings— Olan and his the visitor,—flew in tandem around the peninsula, over the railroad bridge 

Osprey fledglings playing together, courtesy of Flicker. 

to the east and back over the lake, sailing on the breeze. It was clear the young birds  were not in total control of their flight as the wind directed their path. After at least ten  minutes of play, the birds parted and Olan returned to his nest. Shortly afterwards,  Rosie let the wind take her up and flew out over the creek and back. 

An hour later, Olan, flying high in the sky at least a hundred feet up, was cruising  around the point screaming repeatedly, drawing attention to himself. In short order a  second and third Osprey fledgling flew from the direction of Myers Hill to join him. The  three flew back and forth over the point, changing altitudes from a hundred feet and  higher to nest height. The three flew off toward the entrance to Myers Park before  parting. Olan flew in wide circles back to his nest, while the others played where they  were before heading to their nest(s). A bit after Olan landed, Lilibit wingersized in the  breeze until it took her up and she got her first real air. Now we have three fledglings  airborne—it’s a grand sight! 

For the next month, fledglings from the Salt Point nest and the five nests nearby will be  flying about, making Ospreys a common sight over the lake. With so many Osprey  about, it’s it a good time to recognize some of their environmental contributions. Ospreys are beneficial to both the aquatic and terrestrial environments they live and  hunt in. As efficient apex fish-eating predators, Ospreys play an essential role of  maintaining healthy fish populations without over-fishing. This is not the case with some 

other migratory species, such as double-crested cormorants, which fish out areas and  move on. 

Ospreys also promote the productivity of the land where they live by fertilizing it with  their nutritious waste. By excreting their fishy, oily, nitrogenous excrement around their  nests and perching sites, these birds transfer nutrients and energy obtained from the  lake ecosystem to improve the health of the terrestrial system. In contrast, Cormorant  guano is highly acidic, killing ground vegetation and irreversibly damaging nest trees.  Cormorants also destroy vegetation directly by stripping leaves and small branches  from trees for nesting material and having branches break under the weight of the  nests. Loss of trees can lead to increased erosion, particularly on sand spits and barrier  beaches. 

Ospreys have beneficial interspecific interactions with many species. Their big bulky  nests provide safe nesting spaces underneath for small, cavity nesting birds such as  house sparrows and tree swallows. Beavers are helpful to the Ospreys by damming up  rivers to create shallow ponds with easily accessible fishing. Trees in these new ponds may die, becoming perfect substrates for the Osprey’s nests. Brown bears and great  blue herons also share the same shallow fishing habitat as the Osprey. All three are  dependent on fish for a reliable source of nutrition; however, they don’t directly compete  for food, because they prefer different kinds and sizes of fish. Both the bears and heron  also supplement their fish diets with plants and other animals. 

Ospreys are known to be sensitive to pollutants, serving as great indicator species or  “sentinel species” for analyzing the health of the body of water and the fish they  consume. (See Blog #350.) Ospreys, by virtue of being apex predators in their food web  and their ability to live in near humans, are an ideal sentinel species like canaries can  detect carbon monoxide contamination in coal mines. Ospreys help researchers  evaluate increasing the degree of environmental contamination in rivers and lakes.  

When toxic chemicals pollute rivers, streams, and lakes, they inherently pollute the fish living there. The long-lasting toxic chemicals that were banned decades ago remain in  marine and freshwater food chains today at varying levels. By example, the pesticide  DDT and insulating chemicals known as PCBs and PBDEs is found in the Chesapeake  Bay. 

PBDE and PCB, courtesy of ResearchGate.

Schematic showing PBDE blocking genetic, liver, hypothalamus, and  

neurological pathways in higher vertebrates, courtesy of Flicker. 

Ospreys are also sensitive to flame retardant PBDEs and pharmaceuticals intended for  human use. Even the chemicals used in fracking for natural gas can foul groundwater  and aquifers and affect the Ospreys. Since Ospreys are so sensitive to chemical  pollutants, their food sources must be free of contamination. Otherwise, the Ospreys  catch and eat the affected fish, consuming their harmful chemical content, and passing injurious chemicals to their offspring.  

There is a cautionary sign: the blood of osprey nestlings from industrial areas in the  northeast carried low levels of a biological marker for genetic damage. Levels of the  marker were highest in one of the Chesapeake Bay's most polluted areas, near  Baltimore's Back River wastewater treatment plant. The Osprey nests near that plant  did poorly at raising chicks to adulthood. The genetic damage is not enough to affect  reproduction, but it may be having subtle, undetected effects, and warrants more  research. 

Eyes to the sky!  

Candace 

Candace E. Cornell  

Friends of Salt Point  

Lansing, NY  

cec222@gmail.com 

What to do if you find an injured animal? 

Call Cornell’s Swanson Center 

at  

607-253-3060. 

The Janet L. Swanson Wildlife Health Center, an annex of the Cornell University  Hospital for Animals, is a veterinary hospital dedicated solely to the treatment of ill or  injured native wild animals. They provide expert medical and surgical care for over  1,000 patients annually, from locally and across the state of New York, with the goal of  releasing them back to the wild. The Wildlife Health Center operates within Cornell  University, a registered nonprofit, and relies largely on public donations.  

EYES ONOSPREYS 

WATCH! 

Salt Point Osprey Nest Cam 2021 

READ! 

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

VISIT! 

Cayuga Lake Osprey Trail