04 October, 2015

Hunting over the Gulf?

On Saturday, Island Girl halted her migration and remained on perches well offshore in the Gulf of Mexico. We assume these are most likely oil platforms as it has long been known that peregrines stop off on such structures every fall to perch, rest and hunt.

There are many eye witness accounts of migrant peregrines using these platforms. Sometimes several have been reported on the same oil rig.

There are also migrant peregrines are reported from cruise ships plying the Gulf waters during the fall migration period. I think I need a grant to study peregrine migration on cruise ships!

Anyway, Island Girl flew only 59 km (37 miles) on her 15th day of migration, apparently to another platform to the SSW. She remained there Saturday night.

It is also well known that huge numbers of passerines and other birds are migrating across the Gulf right now.
From a high hunting perch on the platforms, Island Girl would have her pick of prey, seeing it coming well out across the water and likely flying right at her.

Peregrines are famous for hunting prey over open bodies of water. It is my experience that many of them specialize in this type of hunting. I have seen this behavior all over the world but especially here in the San Juan Islands of Washington near where I live.

 The reason it is such an effective hunting technique is that the prey simply has no place to hide. There is no cover over the open ocean. No trees, no grass, no buildings. Nothing except the oil platform itself.

And these are known to have sometimes thousands of passerines landing on them, perhaps exhausted or disoriented, perhaps fighting a strong headwind. So these massive structures are sort of centers where much is happening.

I can imagine an oil platform loaded with both peregrines and passerines at the same time. What a sight that would be.


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