Wednesday, June 17, 2009


In the last two posts I've been talking about some great resources for educating oneself in aspects of wildlife and the outdoors, but I think its time to dive right in and start discussing the critters, plants and pests that make the natural world so interesting. For the next few day's I'll be discussing a few bird species of interest to the region and then see where it goes from there. Hopefully by the weekend I can get into some carnivore studies and genetic improvement projects.

Here in Northwestern Montana we are lucky enough to have a nice variety of predator birds to admire. One of my personal favorites to study about is the osprey (Pandian haliaetus) because it is one of the most specialized hawks around. Not only is this bird of prey spectacular to look at but its amazing to study as well. Their feeding/hunting behaviors alone are well worth any amount of time spent researching them.

General characteristics:
Osprey are a diurnal fish-eating bird of prey and are part of the family Accipitridae. This large hawk can reach up to 2 ft in length, weigh around 4 lbs and can have a 6 ft wingspan. Though the wingspan can be huge for a bird of its general size the wings themselves can have a crooked appearance from being held slightly arched in flight. Osprey are brown on the upperparts and predominantly white on the head and underparts, with black eye patches and wings. A short tail and long, narrow wings with four long, finger-like feathers, and a shorter fifth, give it a very distinctive appearance. One interesting tid bit is that the osprey is the only raptor species that has a reversible outer toe which allows for better gripping of slippery fish with two toes in front and two toes in back. There are four generally recognized subspecies although the differences are small. The sexes appear fairly similar, but the adult male can be distinguished from the female by its slimmer body and narrower wings. The breast band of the male is also weaker than that of the female, or is non-existent, and the underwing coverts of the male are more uniformly pale.

Osprey can tolerate a wide variety of habitats as long as there is a nesting site near an open body of water with enough fish to provide an adequate food supply and is found on all continents except for Antartica. The Osprey breeds by freshwater lakes, and sometimes on coastal brackish waters. Here in Montana osprey nests are typically found in dead trees or on other prominent supports near water such as large rivers and reservoirs.

Fish make up 99 percent of the Osprey's diet. The osprey's hunting habits are very unique. Most often the bird perches on conspicuous poles or trees near the water which allows a wide field of view to find their prey under the surface of the water. Once a potential fish is spotted the osprey takes off and flies directly over the water. Swooping down from above the osprey selects its fish at about 50 ft above the water, after which the bird hovers momentarily then plunges feet first into the water.[After catching the fish considerable effort is needed to get airborne again. As it rises back into flight the fish is turned head-forward to reduce drag. The Osprey is particularly well adapted to this diet, with reversible outer toes, sharp spicules on the underside of the toes, closable nostrils to keep out water during dives, and backwards-facing scales on the talons which act as barbs to help hold its catch.

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