A father-and-son team of biologists says seabirds are the best way to keep track of increasing chemical contamination of the world's oceans.

The biologists say the birds' wide-ranging flights make them a cheap and effective way to gather information over vast stretches of ocean.

Kyle Elliott of the University of Manitoba says in a paper published today that feathers and eggs retain traces from all the environments birds have passed through.

Elliott argues one visit to a seabird colony can provide information that would cost millions of dollars to check out in a research vessel.

Many countries already conduct such research.

Elliott says new technologies such as tiny GPS transmitters are expanding the possibilities.

He adds the growing number of chemicals leaching from plastic in the oceans will make closer wildlife monitoring essential to understand what's happening.