Osprey nest at Barr Lake Nature Preserve, Brighton, Colorado (6/4/2017)
This platform has been constructed for the pair to nest and reproduce in the safety of a world famous wildlife habitat at Barr Lake, Colorado. This year (2017), two chicks are in the nest.
Osprey nests are built of sticks and lined with bark, sod, grasses, vines, algae, or flotsam and jetsam. The male usually fetches most of the nesting material—sometimes breaking dead sticks off nearby trees as he flies past—and the female arranges it. Nests on artificial platforms, especially in a pair’s first season, are relatively small—less than 2.5 feet in diameter and 3–6 inches deep. After generations of adding to the nest year after year, Ospreys can end up with nests 10–13 feet deep and 3–6 feet in diameter—easily big enough for a human to sit in.
Ospreys are superb fishers and eat little else. Fish make up 99 percent of their diet. These birds are nearly always near ponds, rivers, lakes, and coastal waterways around the entire world, except for Antarctica.
The osprey is one of the most widespread birds of prey and can be found on every continent except Antarctica. Because of its raptor look and eagle-like appearance, they are also called sea eagles, river hawks, fish hawks, sea hawks.
Cool Facts from ALL ABOUT BIRDS
- An Osprey may log more than 160,000 migration miles during its 15-to-20-year lifetime. Scientists track Ospreys by strapping lightweight satellite transmitters to the birds’ backs. The devices pinpoint an Osprey’s location to within a few hundred yards and last for 2-3 years. During 13 days in 2008, one Osprey flew 2,700 miles—from Martha’s Vineyard, Massachusetts, to French Guiana, South America.
- Ospreys are unusual among hawks in possessing a reversible outer toe that allows them to grasp with two toes in front and two behind. Barbed pads on the soles of the birds’ feet help them grip slippery fish. When flying with prey, an Osprey lines up its catch head first for less wind resistance.
- Ospreys are excellent anglers. Over several studies, Ospreys caught fish on at least 1 in every 4 dives, with success rates sometimes as high as 70 percent. The average time they spent hunting before making a catch was about 12 minutes—something to think about next time you throw your line in the water.
- The Osprey readily builds its nest on manmade structures, such as telephone poles, channel markers, duck blinds, and nest platforms designed especially for it. Such platforms have become an important tool in reestablishing Ospreys in areas where they had disappeared. In some areas nests are placed almost exclusively on artificial structures.
- Osprey eggs do not hatch all at once. Rather, the first chick emerges up to five days before the last one. The older hatchling dominates its younger siblings, and can monopolize the food brought by the parents. If food is abundant, chicks share meals in relative harmony; in times of scarcity, younger ones may starve to death.
- The name “Osprey” made its first appearance around 1460, via the Medieval Latin phrase for “bird of prey” (avis prede). Some wordsmiths trace the name even further back, to the Latin for “bone-breaker”—ossifragus.
- The oldest known Osprey was at least 25 years, 2 months old, and lived in Virginia. It was banded in 1973, and found in 1998.
CATAGORIES OF BIRD STATUS FOR CONSERVATION
• Extinct (EX) – No known individuals remaining
• Extinct in the wild (EW) – Known only to survive in captivity, or as a naturalized population outside its historic range
• Critically endangered (CR) – Extremely high risk of extinction in the wild
• Endangered (EN) – High risk of extinction in the wild
• Vulnerable (VU) – High risk of endangerment in the wild
• Near threatened (NT) – Likely to become endangered in the near future
• Least concern (LC) – Lowest risk; does not qualify for a higher risk category. Widespread and abundant taxa are included in this category.
• Data deficient (DD) – Not enough data to make an assessment of its risk of extinction
• Not evaluated (NE) – Has not yet been evaluated against the criteria.
SHAKESPEARE ON THE OSPREY
Shakespeare in Act 4 Scene 5 of Coriolanus:
“I think he’ll be to Rome
As is the osprey to the fish, who takes it
By sovereignty of nature.”