Blog #366 A World Awakes: Osprey Migrate North

Arrows indicate fall migration, reverse the arrows for the spring migration, courtesy of RSP. 

The global range of Ospreys is impressive, with representatives found around the  world except for in Antarctica. Although non-migratory Osprey populations occur in  Australia, the Caribbean, and the southern US, most Ospreys breed in the northern  hemisphere and fly south to over-winter. These 2,000–4,000 mile journeys are difficult  and dangerous; evolution would only tolerate such risky behavior if there was a  considerable upside.  

On migration, Ospreys can fly over 250 miles in one day in fair weather. In North  America, Ospreys travel as far as Central and South America and winter as far south as  Argentina (see map below). Osprey breeding throughout Europe and Scandinavia overwinter in West African countries like Senegal and Gambia where the climate is pleasant and fish are plentiful. Eastern European and some Russian Ospreys migrate  down through East Africa skirting the Sahara desert, traveling as far south as South  Africa. Much less is known about the Russian and Chinese Ospreys because of the lack  of free exchange of scientific information. Chinese and other Asian Osprey are thought  to go due south into India, South East Asia, and Japan.

Map showing the spring and fall migration routes of three GPS tracked Ospreys, courtesy of OspreyTrax. 

Why don’t Ospreys simply swear off these strenuous and dangerous 2,000-4,000 mile  migrations and live full time in the south? The chief reason for the migration appears to  be to take complete advantage of the long daylight hours during the northern  hemisphere summer. The father Osprey’s main job during the summer breeding season  is to hunt and keep his family supplied with food. These extra daylight hours enable him  to catch sufficient fish to feed his growing and demanding family. There are also far  fewer nest thieves such as poisonous snakes, climbing mammals, and other birds in the  Northern Hemisphere threatening the Ospreys’ eggs and flightless chicks than in  southern climates.  

Hatching caddisfly on lake, courtesy of Flyfishing. 

Ospreys take full advantage of the seasonally abundant fish in the water bodies. Insects  such as mayflies, caddisflies, stoneflies, midges, gnats, and smuts live as larvae in the  depths of the lakes and streams. In summer, these insects rise to the surface and 

emerge into the air as adult flies ready to breed. Trout and other predatory fish follow  the insects toward the water’s surface, moving within range of diving Ospreys, which  can only catch fish in the top 3 feet of the water column.  

Fish follow the hatching caddisfly to lake surface, courtesy of flyfishinginthe smokies.com. 

Short northern winter days cause insect larvae to move deeper in the waterbody, taking  the trout and other fish with them. Shallower waters also freeze over, cutting off access  to the fish. In winter fish stay at the bottom of water bodies to escape the cold and the  ice-covered surface. An Osprey remaining north would likely starve.  

Ospreys gathering nest materials after returning to its home, courtesy of Andy Morffew 

Depending on the weather, Ospreys usually arrive in Europe and North America in late  March to early April and head south again around September. Each migration can take  a perilous 4–6 weeks as the birds fight storms and risk starvation. This year along with  returning adults will be a group of young birds, almost 2 years old, who migrated in the  

fall of 2020. Over 50% of all young raptors die in their first year, usually of starvation. As 

newly fledged juvenile Osprey, they barely learned to fish before they left on migration. 18 months later these returning young birds are sexually mature but probably won’t  reproduce. This year they will concentrate on finding a mate and starting a nest. 

Eyes to the sky! 

Candace 

Candace E. Cornell 

Friends ofSaltPoint 

Lansing, NY 

Cayuga Lake Osprey Network 

NY cec222@gmail.com 

Osprey Annual breeding cycle, courtesy of RSP.

EYESTOTHESKY! 

WATCH! 

Salt PointOspreyNest Cam 

READ! 

OnOspreyTime: Ospreys of Salt Point 

VISIT! 

Cayuga LakeOspreyTrail 

 

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