Friday, April 29, 2016

Birds with Fish: Osprey

Since I recently finished a series on Birds with Bugs, I thought a series on Birds with Fish was in order. This topic, however, has become a little more challenging since moving to the Arizona desert in 2002. 

Nonetheless, we start today with the Osprey. 

Osprey distribution is worldwide except for Antarctica. In the western hemisphere they winter in South America and Summer in the Northwest United States and most of Canada. They breed during the summer months throughout their summer range. Obviously, they can be found between these two zones during migration. 

Their diet is almost entirely fish. In fact, it is the only bird of prey that feeds exclusively on fish.

Therefore, ospreys are found near water, either fresh or salt, where large numbers of fish are present. They are commonly found around major coastal estuaries and salt marshes, but also regular around large lakes, reservoirs, rivers. Hence a smaller population in Arizona. Migrating Ospreys are sometimes seen far from water, even over the desert.

They fly slowly over water, pausing to hover when fish are spotted below; if  a fish is close enough to surface, the Osprey plunges feet-first, grasping prey in its talons.

They carry their catch parallel to their own body and head first to keep it aerodynamic (as seen in the first photo).

Their outer toe is reversible so it can grasp with three toes forward and one toe backward or with two toes forward and two toes backward (giving them a more stable grip in flight).

Ospreys typically lay 2 to 4 eggs. Their eggs don't all hatch at once however. It is usually five days between the first and last hatchling. Females stay with the chicks most of the time. The male is responsible for finding food and bringing it to the nest. Ospreys often use the same nest for years. Nests are usually near water where food is present.

Osprey with Trout above Ernst Lake, British Columbia

Osprey Eating Fish at Agua Caliente, Arizona

Osprey with Trout at Lake Chopaka, Washington

Osprey with Fish at Seedskadee National Wildlife Refuge, Wyoming

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