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Raptors Lured to New Habitat

By Mia Davidson and  Jan Sattler
By Mia Davidson and Jan Sattler

June 1972 is considered the date of the first important victory in the modern environmental movement. That is when DDT was banned by the EPA because it was shown that using the pesticide led to eggshell thinning in raptors and other birds, including pelicans. Because the thin shells broke during incubation and limiting reproductive success, bird populations plummeted. The osprey (Pandion haliaetus) was one of the birds hard-hit during this period. Since the early 1900’s, osprey populations had been declining due to hunting and egg collection. Exacerbated by DDT that came into common use after World War II, populations dropped so far that they were placed in the Department of Interior’s Redbook, which contained the first official list of species potentially facing extinction.

The osprey, Pandit haliaetus.
The osprey, Pandit haliaetus.

The osprey is a large, slender raptor with a length of almost two feet and wingspan of five feet. Colored dark brown with white undersides, they have a white head and throat with a black band, resembling a mask, running from its beak, across its yellow-orange eyes onto its back. While in flight, the wings have a distinctive downward bend and typically, four long feathers visible at the end of each wingtip. Their beaks are black with a sharp hook and their legs and feet are light gray ending with sharp black talons. They are piscivores and dive for fish swimming under the surface of the water. To maintain the water resistance of the feathers, they secrete a heavy oil that gives the birds a characteristic odor. They live over 25 years.

The single species of animal that is found throughout the world except for Antarctica, osprey’s live in a wide range of habitats near their food source along coastlines, marshes, lagoons, rivers and lakes. Except for a few resident populations that are found in the lower latitudes in the Americas (such as Southern California), ospreys migrate several thousand miles to their wintering grounds in South America in the fall. In the spring, they return to their summer breeding grounds in North America. Resident pairs breed in winter and spring before migratory pairs, which breed in spring and summer.

Ospreys become sexually mature at three years of age. Generally mating for many years and sometimes for life, osprey pairs neither migrate nor winter together but reunite annually at their breeding sites and stay together nearly five months to breed and raise their young. Nests are located high in the branches of live or dead trees, cliffs and rocky outcrops as well as buildings, electric towers, poles and other man-made structures. The nests are large reaching six feet in diameter and up to 13 feet deep. Ospreys return to the same nest or build a new nest close to previous nests. The female lays two to four eggs, which hatch after five weeks. The male hunts for fish, which he gives to the female and they both feed the chicks. The chicks fledge in approximately eight weeks, but remain in or near the nest for an additional eight weeks before departing.

Ospreys are vulnerable to human activities, which include illegal shooting in certain parts of their range, car collisions, electrocution by high power lines, environmental contaminants and increasingly wind farms. The great horned owl has been known to be a predator of adult and baby osprey. In addition, nests can be vulnerable to predation by raccoons, opossums, snakes, owls, ravens, crows and other birds of prey.

 

Fossil evidence indicates that osprey species have been in Southern California since the Middle Miocene epoch, 11 to 15 million years ago. But for nearly 100 years, ospreys did not breed in California south of Santa Barbara.

In 1993, an elevated platform was erected in the Upper Newport Back Bay with the hopes of attracting a breeding pair. In 2006, after many years of courtship, a breeding pair successfully mated and produced two chicks. Since then, the same birds have reproduced several times and there are several other breeding pairs in the area. In fact, an osprey offspring born in 2008 on the Upper Newport Back Bay platform has now successfully reproduced on a platform in the San Joaquin Wildlife Sanctuary in Irvine. One can usually see ospreys and the breeding platforms when visiting the Upper Newport Bay Nature Preserve. On weekends, naturalists lead two-hour kayak tours offered by the Newport Bay Conservancy. These are family friendly, inexpensive, informative and fun. Ospreys have been increasingly seen in Laguna Beach. In north Laguna, an osprey perches almost daily on a flag pole overlooking Shaw’s Cove interacting with another osprey that perches fairly often on a telephone pole just south of the main entrance of Crescent Bay. Could it be an indication of a new breeding pair?

 

Residents and ocean swimmers Mia Davidson and artist Jan Sattler are actively involved in protecting Laguna Beach’s coastal resources.

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