What could you conclude if you observed an animal with feathers that couldn't fly?

There are many species of Flightless Birds alive today, including the Ostrich, Emu, Kiwi, Cassowary and the many varieties of Penguin.

As an adaptation, flight is an Excellent way of avoiding predators, but it uses a lot of energy and keeps the animal small and light (and so quite vulnerable)

So if an animal could somehow do without such high energy demands, it would definitely evolve to do without them.

It is not a coincidence then that the vast majority of flightless bird species have evolved on islands where predatory mammals are non-existent, or of low threat.

Recently extinct flightless bird species such as the Dodo of Mauritius and the Moa of New Zealand became extinct due to a powerful predator they had no experience of, or protection against (largely because they couldn't fly away!).

That predator was Man.