Posted: 28/10/2015 at 10:21
Falcons inc Peregrines, Sparrow hawks, Merlin and Hobby give chase when hunting there food in the air and rarely pounce on prey in trees or on the ground.
Buzzards, Eagles, Kites and Harriers normally quarter an area of land to sneak up and pounce on the ground when hunting and rarely take prey in the air.
There are always exceptions to the rules though.
A peregrine or a Goshawk would have no problem harassing a skein of geese on migration, both would take a goose as prey in the air.
Geese only harass other birds on the nest when breeding to keep predators away from eggs and young and wouldn't waste there time harassing another species the rest of the year. Herons, Crows and birds of prey will harass each other readily all year round.
Young, immature Kites, Buzzards and Harriers will "Try It On" with flocks of Geese and Ducks low over marshes and fens but give in very quickly and the geese and ducks don't get too excited.
Skein's of geese usually fly high, higher than an Eagle, Kite, Buzzard or Harrier would normally interest them.
I think that your bird of Prey was almost certainly a Peregrine Falcon and an immature bird too trying it on not really knowing for sure just what its capable of yet.
A Peregrine will take, kill and carry a Mallard no problem, a goose is really testing the limits of a powerful falcon but a youngster has a lot to learn and when hungry will have a go at anything.
There are other larger European Falcons that will take, kill and carry geese on the wing but these are very rare in the uk.
A skein of geese wouldn't even flinch at the sight of an Eagle, Buzzard, Kite or Harrier, Crow(s) or Herron(s) on migration and they wouldn't bother them. A Falcon or a Goshawk would very definitely upset them as these birds do pose a serious threat.
Geese, Ducks and Eagles inc Sea Eagles live together largely harmoniously not normally bothering each other outside the breeding season.