{"id":297,"date":"2017-10-13T16:30:59","date_gmt":"2017-10-13T16:30:59","guid":{"rendered":"http:\/\/wordpress.viu.ca\/biol325\/?p=297"},"modified":"2017-10-13T20:02:54","modified_gmt":"2017-10-13T20:02:54","slug":"auspicious-sign-of-the-osprey","status":"publish","type":"post","link":"https:\/\/wordpress.viu.ca\/biol325\/2017\/10\/13\/auspicious-sign-of-the-osprey\/","title":{"rendered":"Auspicious Sign of the Osprey"},"content":{"rendered":"

Take a minute to imagine: <\/strong><\/p>\n

So you\u2019re finally on vacation and have just arrived in the Pacific Rim National Park, on the West Coast of Vancouver Island. You get out onto the beach and smell the fresh salty air and hear the waves crashing around you. You spot a flock of sandpipers down at the north end of the beach, and you begin walk in that direction, in hopes of a closer look. It\u2019s a long relaxing stroll, and the flock of sandpipers eventually move on before you reach them. As you walk down the beach you get lost in thought, combing the sand for cool shells to inspect.<\/p>\n

You\u2019re taken by surprise when you see a large, dark, shadow flit across the sand. Looking up you realize you\u2019re about to catch a magnificent show as a hawk circles high over the water. It\u2019s probably an osprey you think, due to the all-white body and covert feathers, and the dark wings, but growing up in the interior you\u2019ve only ever seen them near freshwater. Once you hear its short, shrill whistle you know for sure what you are witnessing. Suddenly, it dives straight down towards the water, at an impressive speed, and just as it gets to the water\u2019s surface, its feet plunge in, and out, in an instant. It flies away to its nest clutching a fair-sized fish, and leaves you with a feeling of promise for the good things to come during your stay in the park.<\/p>\n

Hopefully you\u2019ve all had the pleasure to witness such an event; whether you have or not, I recommend you read on about the fascinating life of the osprey, and then head to the nearest beach!<\/p>\n

Key Characteristics of an Osprey<\/u><\/strong><\/h3>\n

Size:<\/strong> Ospreys (latin name: Pandoin haliaetus<\/em>) are large hawks, with a body around 0.6 metres long, (Sullivan, 2017), a wing span of 1.5 -1.8 metres and a typical weight ranging from 1.5 \u2013 2 kg. This can vary though; as with most raptors, female ospreys are generally weigh 15 -20% more than males. Body size can also vary with location: ospreys in northern latitudes can be as much as 12 \u2013 15 % larger than those living closer to the equator (Bierregaard et.al., 2016).<\/p>\n

Diagnostic Features:\u00a0<\/strong>(Bierregaard et.al., 2016)<\/p>\n

Seen from below:<\/strong><\/p>\n

White body and primary coverts (the shoulders)<\/p>\n

Dark wings, brown speckled with white<\/p>\n

Distinctive thick black line through the eye<\/p>\n

Yellow eyes<\/p>\n

Wings bent at the shoulders<\/p>\n

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Underside of an adult osprey.<\/p><\/div>\n

From above:<\/strong><\/p>\n

All dark brown<\/p>\n

Dark on tail<\/p>\n

White on top of the head<\/p>\n

Small head compared to size of the body<\/p>\n

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Aerial view of an adult osprey in flight.<\/p><\/div>\n

 <\/p>\n

Juveniles:<\/strong><\/p>\n

Browner feathers with pale edging<\/p>\n

Underside of primary coverts have a reddish-buffy colour until their second molt occurs at age 2<\/p>\n

Orange eye<\/p>\n

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Female juvenile osprey. Note the characteristically orange eyes.<\/p><\/div>\n

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The underside of a juvenile osprey.<\/p><\/div>\n

Chicks:<\/strong><\/p>\n

Very fluffy!<\/p>\n

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An osprey chick looks longingly at it’s mother, waiting for fish no doubt.<\/p><\/div>\n

Beware of Look-alikes:<\/strong><\/p>\n

If you haven\u2019t identified an osprey by its shrill whistle (listen here<\/a>), it is possible to confuse it with look-alikes also living near the water, such as the Greater Black-Backed Gull or a Bald Eagle (Bierregaard et.al., 2016).<\/p>\n

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Aerial view of a Greater Black-Backed Gull soaring. Distinguished from an Osprey with it’s all white underside, white tail and white head.<\/p><\/div>\n

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Easy to distinguish from the Osprey, this adult Bald Eagle has an all white head a tail and has an entirely dark body and wings underneath.<\/p><\/div>\n

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Juvenile Bald Eagle. Note an osprey would have a white belly and head, with a thick dark stripe through the eye, and a deeper bend at the shoulders of the wings.<\/p><\/div>\n

As you can see, both the body and the wings are either fully dark or fully white in these birds, in contrast with the osprey\u2019s dark wings and white body. In the juvenile bald eagle, there is is too much brown on the body and it does not share the characteristic deep shoulder bend of an osprey.<\/p>\n

Diet: <\/strong>These raptors have a highly specialized diet and eat almost exclusively fish. In fact, research shows their diet to be 99% fish in most areas. They will often feed mainly on only a few types of fish, which vary regionally; in British Columbia, important ones include bullheads, carp, large-scale suckers, cutthroat trout, smelt, and surfperch (Bierregaard et.al., 2016).<\/p>\n

Ospreys have several special adaptations allowing them to have a high success rate fishing. These include zygodactyl feet with a reversible outer toe that allows them to grab fish with 2 toes in front and 2 toes behind (2015, All About), they also have barbed foot pads which help them hang on to slippery fish, and an incredibly keen sense of vision, having been known to dive for a fish from a height of 40 metres! (Sullivan, 2017)<\/p>\n