The osprey is a brief visitor in Oklahoma–we’re on its migratory route from its summer breeding grounds in the north to its winter grounds in Central and South America. I can usually tell when fall migration has really picked up, is when I can spot an osprey flying over Boomer Lake.
This is a very distinctive hawk in flight–once you know what to look for. When they fly, their wings are at an angle that they look like a flying M when viewed from below.
In terms of size–they’re somewhere between a red-tail hawk and the bald eagle.
These birds have brown feathers along their back and wings, where the chest and under feathers are white. They also have a broad brown eye-stripe with a prominent white head.
The western osprey is a cosmopolitan bird, that depending on the time of year, and how close you are to a body of water (lake, river, ocean tributaries, and so forth), you might be able to spot an osprey.
They prefer shallow fishing areas (as they can only dive about three feet into the water after fish), so if spotted around deeper waters it is due to a school of fish being near the surface.
Since the western osprey is usually a migratory bird (there are only a few places within the US that they are a year round resident), they rack up the miles over their lifetime. Their breeding range extends from Alaska and Canada (making up the northern edge) to pockets within the Rocky Mountains and various places along the east coast. This means that during migration, an osprey could be flying over a thousand miles or more to go from their breeding grounds to their wintering grounds (which is usually Central & South America, though they can be spotted along the Gulf coast).
Since they do feed solely on fish, their nesting sites need to fit the following criteria: be within twelve miles of an adequate supply of fish, the nest has to be in a tree tall enough to deter climbing predators (such as raccoons), and the summer has to be long enough to ensure the chicks have time to fledge.
Oklahoma is directly in the middle of the migratory route, though with the way breeding ranges at time expand, we could possibly start seeing breeding pairs within Oklahoma (at least towards the edge of the summer range in Arkansas).
The best place to try to spot them are around bodies of water–as their sole food source is fish. I’ve managed to catch a glimpse of a migratory osprey at Boomer Lake a couple of years ago–I never saw it dive in for the fish, but I did catch it soaring and looking for food.
The osprey feeds primarily on fish (either fresh or sea), to where the fish comprises about 99% of the diet. The other 1% is usually made up of the rare hunting of other birds, snakes, voles, squirrels, muskrats and salamanders.
Depending on the year, osprey females will lay one to four eggs. If she lays more than one egg, the first one will hatch at least five days before the last one (so there is delayed hatching), giving the older chicks a better chance of survival. Like many raptor chicks, the older chicks may be more dominate and semi-aggressive towards its younger siblings. In times of possible food shortages, the younger chicks may starve as the older chicks push them out of the way to be the first to grab the food from the parents.
The osprey is another raptor that made a comeback after the banning of DTT. While their comeback overall has been a success, they are still listed as endangered or threatened in certain states due to the over use of agricultural pesticides that wash or leach into the lakes and rivers (resulting in poisoned fish that they catch and eat), loss of nesting sites (due to tree removal and shore development), plus the latest threat–fishing line and other twine that adults try to weave into the nests. This may result in the younger birds getting their legs caught in the twine and either causing injury or possible death (if they are unable to free themselves).
So we should also be thinking of different ways of discarding twine, wires, and so forth instead of possibly just throwing them outside. What we think may not be a danger to wildlife, could actually turn out to be life-threatening to certain species.