Just Visiting?? A Parasitic Jaeger

The Story

Yesterday I watched a Murder of Crows swarm a bird I thought was a raptor. They forced it to land where they were going to tear it to shreds.
I interfered by tossing out peanuts, but I still had to chase a few crows away from the bird. He/she didn’t resist and, as you see in the photos, allowed one Crow to drag him/her by the wing.
I ran over, the Crows dispersed, and off flew the Jaeger. He/she didn’t appear to be injured, so all ended well.

I sent a photo to a birder I know as I had never seen this bird before in our area. She had no idea, so she asked other birders for identification. None of them thought this bird would be in our area. After some research, they agreed it was a visiting Jaeger.
Cool, huh.

Parasitic Jaeger – Stercorarius parasiticus

Lives in the Ocean, coastal bays, lakes (rarely); tundra (summer). Spends most of year at sea, concentrating over continental shelf within a few miles of land, rarely far out in mid-ocean. Breeds in open country of far north, mostly tundra, also rocky barrens and coastal marshes. Immatures and non-breeders may remain at sea all year.

Migration

Often seems to follow general trend of coastline, a few miles offshore; some may regularly migrate over land. A few remain in winter as far north as North American waters but most go farther south, some reaching southern Australia, Africa, South America.

Feeding Behavior

At sea, does much of foraging by chasing other birds and forcing them to drop their catch; also dips down in flight to catch fish at surface. On breeding grounds, also hovers and swoops down to catch prey, and feeds while walking.

Eggs

2, sometimes 1-3. Olive to brown, rarely blue, spotted with brown. Incubation is by both sexes, 25-28 days. Young: Downy young may leave nest a few days after hatching, but remain in vicinity. Both parents feed young, by regurgitation. Young can fly at 25-30 days, but remain with parents for a few more weeks.

Young

Downy young may leave nest a few days after hatching, but remain in vicinity. Both parents feed young, by regurgitation. Young can fly at 25-30 days, but remain with parents for a few more weeks.

Diet

Includes fish, birds, rodents. Diet at sea and at coastal nesting areas is mostly fish stolen from other birds. On land, also eats many birds and their eggs, rodents, insects, berries. Less dependent on lemmings and other rodents than the other jaegers. 

Nesting

Usually first breeds at age of 4-5 years; in one study in Europe, birds of pale morph tended to start nesting younger than dark birds. May nest in colonies or in isolated pairs. Early in breeding season, pairs or groups perform acrobatic display flights. Courtship involves upright posturing, calling; male feeds female. Nest site (selected by male) is on the ground in the open, sometimes on a slight rise. Nest (built mostly by female) is a shallow depression, usually with a sparse lining of plant material.

Info from Audubon

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