TORONTO -- Birds of a feather may flock together, but what about those that show up to replace other species?

Bird extinctions can leave a significant gap in the food chain of the affected ecosystem.

Sometimes, invasive species are introduced in an attempt to restore the natural order. But does that really work?

In this week's Riskin Report, ۴ý Science and Technology Specialist Dan Riskin looks at on what happens when new birds move in to replace other species – and finds that there really is nothing quite like a dodo.

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