The gull-trapping trick was initiated by a four-year-old orca in a tank at Marineland at Niagara Falls in Ontario, Canada, according to a report in next Saturday's issue of New Scientist.
  
The mammal discovered he could lure seagulls into his tank by spitting regurgitated fish onto the water's surface.
  
He then lurked below the surface, waiting for a gull to grab the fish, and then seized the bird in its open jaws.
 
After a few months of feathered snacks, the killer whale started to be joined his younger half-brother, and soon thereafter they were joined by their mothers, a six-month-old calf and an older male.

Clever 
  
The clever whales are able to catch three or four gulls on some days.
 
In June, researchers showed that wild dolphins off Australia taught each other to use sponges to protect their snouts while grubbing for food on the sea floor.
  
And earlier this month, US scientists reported on two groups of chimpanzees whose members adopted rival methods to use a stick to coax food out of a feeder.
  
The latest discovery was made by animal behaviourist Michael Noonan of Canisius College in Buffalo, New York, who presented his findings at a conference earlier this month, the British weekly says.