(c) Anthony K. Grafton 2003

Moa Birds and Dodo’s, Please

Can you imagine a real bird big enough to stand in front of a grown man and look down on him? That’s how big some moa birds in New Zealand were before they became extinct several hundred years ago.

Moa (whose name can be both singular and plural, like the word elk) looked something like large, heavy-set ostriches, and lived mainly in forests. Like the ostrich, moa birds could not fly. New Zealand, an island near Australia, was home to a large population of these extraordinary animals until the arrival of the first humans about 700 years ago.

The newly-arrived humans did three things that led to the extinction of moa birds. First, they set fires to clear the land, and this changed the habitat dramatically. Second, human settlers brought rats with them, and these rats fed on the eggs of many native birds that, like the moa, nested on the ground. Third, and most importantly, the first humans in New Zealand hunted the moa bird extensively for food. Today, scientists can easily find piles of bones from slaughtered moa birds in old, dry caves, but these bones are only found in the oldest human settlements, meaning that the moa didn’t last long once humans arrived.

The discovery of moa bones by European scientists in the 19^thcentury played an important role in the development of the then-new idea that animals could become extinct. Previously, most people thought that all animals and plants that had every lived were still living. We now know from fossils and other evidence that thousands upon thousands of species of animals and plants have evolved, thrived, and become extinct during the 4.5 billion years the Earth has existed.

If you think that large birds being hunted to extinction is something that only happened once, think again. Consider the dodo (pronounced doh-doh) bird. This turkey-sized, flightless bird lived on islands in the Indian Ocean until they were first discovered by sailors in the late 1600’s. Because they were relatively big and slow, they made an easy source of food for passing ships. Within 100 years of discovering them, human hunting resulted in the complete extinction of the dodo.

And if you think humans could only wipe an entire species on the other side of the planet hundreds of years ago, have you ever heard of the passenger pigeon?

These examples provide important lessons for us today. Human activities can result in uncorrectable changes in the ecosystem of the Earth. But if each of us considers the consequences of our actions, we can help minimize the damage we cause to the plants and animals that live all around us.