There is a lot of chattering going on around the ‘bird’ world and the one common word that binds people in the United Kingdom with those in San Francisco and Australia is: Osprey. Every continent has Osprey – some more than others. Many of my friends adore them above any of the other feathered friends because they ‘eat fish’. They are sometimes called ‘sea eagles’ but do not confuse them with White-Bellied Sea Eagles. Totally different.
You will find Ospreys on every continent in the world except for Antarctica. And there is no missing them. They have very distinctive plumage that helps them with the glare off of the water when they are hunting. See that black line going from the beak over the eyes and to the back of the head? That will stop the glare from the water so that their great vision, three times that of a human, can help them spot the fish swimming below the surface. If you watch American football you might recall that the players put a black line under their eyes to stop glare – something learned from the Osprey! The soles of their feet are different than other raptors. They are very rough with tiny little barbs. If they were a person you might recommend they go to get a pedicure – that is how rough those soles are. That rough surface helps them to hang on to wet slippery fish that do not want to be an Osprey’s dinner. They have four toes like all other raptors but the Ospreys can do something that others can’t – they can swivel one of those front toes to the back to help hold on to those wiggly fish. Brilliant.
Ospreys are smaller than a Bald Eagle but bigger than the large hawks. They weight 1500-2000 grams (3-4 pounds). They are about 54-58 cm long (21.3-22.8 inches) with a wingspan of 150-180 cm (59 to 79 inches). Their head, throat, and body along with their legs are mostly white. They have black and white banded tail feathers and distinctive black and white wings that bend at the joint. Their beak is black and shaped like a very sharp hook. Their eyes are a beautiful, beautiful yellow.
Female Osprey are about 20-30% larger than the males. The females have a ‘necklace’ of feathers that is darker and more distinctive than the male.
Osprey’s have a distinctive dive and I do not have an image of it. Once they have spotted their prey, they bring their feet forward so they are even with their beak and then catch their prey feet first. They then latch on to the fish with those sharp talons. It is quite spectacular.
How large are the fish that the Osprey catch? The Osprey normally catches fish that are 15-30 cm in length (6-12 inches) and that weight less than 454 grams or a pound. The largest observed catch was 1250 grams or 2.5 pounds. Some researchers believe that they can easily carry up to half their weight.
Do Ospreys eat anything other than fish? The answer is actually yes. While the majority of their diet is fish, Osprey have been observed, on rare occasions, to eat other birds, voles, squirrels, muskrats, eels, and salamanders. Droughts really impact Osprey and their ability to thrive.
The territory of an Osprey will be near a body of water – a lake, a river with lots of fish, along the shores of the oceans and seas. They build their nests off the ground to avoid predators. Originally, Ospreys made their nests in tall trees but, as you know, there is a shortage of structurally sound tall trees.
Those migrating to Canada have been known to make their nests on utility poles. Sadly, this is a huge problem because of electrocutions. So many died that petitions were sent to Manitoba Hydro, a public utility company. Near to Lake Winnipeg, that company began erecting nest platforms for the Osprey. Ospreys actually like human-made nests. It is said that if you provide a nest, the sea hawks will come. And many in Scotland will tell you that is true! Ospreys are loyal and generally return to the same nest year after year.
During the winter, Ospreys head to warmer climates returning to their breeding grounds in spring. Ospreys from the United Kingdom migrate to The Gambia or Senegal with some juveniles known to stay around the coastal areas of Spain. Ospreys from North America migrate to the southern parts of the United States along the Gulf of Mexico, Southern California, the coasts of Mexico and countries of Central America. Some Ospreys do not migrate. They include those living in warmer climates year round such as Australia, Singapore, other parts of Asia, and parts of the southern United States including Florida.
Solly was born on a nest sitting on a barge at Port Lincoln, Australia. She is an Eastern Osprey and they are critically endangered. Look carefully and you can see the satellite transmitter on her back. She has a bright orange band on her left leg and a metal one on the right. Solly is easy to spot and many are taking her photograph as she travels the Eyre Peninsula of Australia moving north from her barge nest. I often report on her movements and from those the researchers are changing their minds about how far Ospreys travel from their natal nest.
One of the most famous Osprey couples has their nest on a 75 foot high World War II Whirley crane in Richmond.
They are Rosie and Richmond and Richmond – well, everyone loves Richmond! Richmond is quite the character. He loves bringing blankets and stuffed toys up to the nest.
One of my most favourite Ospreys is Iris. She is not named after the flower but because she has some very distinctive spots on the iris of her left eye. Iris is the female at the Hellsgate Nest in Montana. For many, many years Iris and her mate, Stanley, nested at the site and raised many chicks. Stanley did not return in 2016. Iris’s new mate, Louis, has proven to be unreliable and the breeding seasons have been unproductive. While most Osprey are thought to live up to twenty-five years, Iris is believed to now be twenty-nine years old.
During the 2020 breeding season, Iris had simply ‘had it’. Louis, her mate, actually had another family. Iris laid her egg on the nest but Louis did not bring her food or come to relieve her. She had to leave the egg to eat – and, of course, the Ravens were watching and they came and ate it. Iris was not pleased. Then a squirrel climbed up the platform and was trying to get on the nest. Take the time to watch this video to the end. It is only four minutes long. I seriously would not mess with a female Osprey when they are having a bad day. I want to add that Iris was seen fishing and she sometimes returns to the nest. Everyone is hoping that she will come back for the 2021 season with a new partner.
Iris may help avian researchers understand how long wild Osprey can lay fertile eggs. We know that with Wandering Albatross, Wisdom, who is 69 years old is still raising chicks.
Ospreys raise only a single brood of chicks a year. There will be anywhere from one to four eggs. Both parents will incubate the eggs although many note that the female is there more than the male. The eggs are hard incubated from the time the first one is laid. This means that the last chick might hatch six days later than the first. This often results in siblicide where there are three or more chicks. The smallest is just that much smaller and seen as a threat to food resources. That said, I have seen Osprey parents do dual feedings, such as Loch Arkaig in Scotland, with three chicks growing up to fledge with no dominance issues. First pips are normally around thirty-six days. First flight dates really vary from 50 to sometimes as much as 60 days with 55 being the average. The chicks will use their natal nest as a home base. Parents will teach the juveniles to fish and will supplement them with fish they have caught for several months after fledging.
Ospreys were severely impacted by the use of DDT and their numbers declined rapidly. Many countries are working hard to reintroduce them to the wild. I highly recommend:
The Woodland Trust Loch Arkaig Nest in the Scottish Highlands. That URL is: https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/osprey-cam/
You can find Richmond and Rosie at: http://sfbayospreys.org/
If you are interested in following Solly, the Eastern Osprey from Port Lincoln, go to: https://www.facebook.com/portlincolnosprey
You can reach the Kielder Osprey Nests through the following URL: https://www.visitkielder.com/play/discover/kielder-ospreys
If you have a favourite Osprey nest, please let me know. I would love to hear about it.
Update on Solly before I leave. Solly is now 157 days old. She spent yesterday back at Eba Anchorage. Locals say she is staying in a small marshy area near the town.
Thank you so much for joining me today. Hope to see you again soon!
Thank you to the streaming cams at SFBay Ospreys, Hellsgate Osprey by Cornell Lab Cams, Woodland Trust and Loch Arkaig, Port Lincoln Osprey FB Page and Wikimedia Commons.