Stuck! Trivia Quiz

Answer:

The best known of the flightless birds are the penguins and the ratites. The latter includes the likes of ostriches, emus, kiwis, cassowaries and rheas. Their flightlessness may have been a force of evolution and, in some cases, domestication and/or selective breeding. A good example of the latter is the broad breasted white turkey, which has been specifically bred to grow big breasts that can be harvested for meat. The end result is that its weight can no longer support it in flight and it is stuck on the ground. The ancestors of the birds that we now use for domestic purposes, such as the chicken and the duck, are, respectively, the red jungle fowl and the mallard. Both have been gifted with flight, however, their tame cousins retain some of that ability but cannot maintain it for any extended period.

So, where or how does evolution come into this? Sixty six million years ago the K-Pg extinction event wiped out three quarters of the plant and animal life on Earth, the latter group being mainly the dinosaurs and large vertebrates that had no flight capabilities. One of the theories that has arisen is that those creatures that did have wings arrived at these environments that were previously dominated by the dinosaurs. The competition had disappeared and they were able to claim these territories for themselves. The food was generally low lying and it was easier to access by walking than flying, until, they lost that ability entirely. Another theory is that those that found themselves in arid or semi arid areas, identified that walking was more economical than flying. Flight, of all the forms of locomotion, expends the most energy. Additionally, this cost increases with the size of the bird. Gigantism in birds also has a correlation with flightlessness though this is not necessarily a requirement. The kiwi is a good case in this point.

The location with the largest number of flightless birds is New Zealand where you will find, aside from the ubiquitous kiwi, various penguin species, (previously) the moa, the weka (M?ori woodhen) and the takahe (a swamphen from the Rail family). Some of the theories put forth for this are that humans did not arrive until a thousand years ago and this, coupled with the fact that there were few large mammals to compete against, made it easier for ground dwelling birds to survive. Their only real rivals were larger birds of prey.

Alright then, which birds are more likely to lose their ability to fly? This can be broken down into three categories;
- Those with shorter wings
- Those that adapt their wings for alternate purposes. A good example is the penguin, which uses its wings for better locomotion in the water.
- Those that molt and lose all of their feathers in one hit at some point during the year.

The next question that leaps up is, if they cannot fly, why then do they have wings? Flightless birds will use their wings for other purposes. The penguin, which has already been mentioned, will use its wings to move underwater. Ostriches can move at high speeds and emus have been known to run marathons of fifty kilometres or more. To achieve this, they will use their wings for balance. Others will use their wings to attract a mate with extravagant courtship rituals. Beyond the courtship there is the provision of protection and food for the family and, in this regard, size is everything... the bigger the bird, the better it is felt that it could provide. This then increases that circle... the bigger the bird the less chance it has of attaining flight.

The last question then, is there a flightless bird that doesn't have wings? So far, the only known species of flightless bird that has (or had - it is now extinct) completely lost its wings was the moa. This New Zealand bird, which was closely related to the cassowary and the ostrich, was a ratite that was hunted out during the 15th century. Studies at the University of Otago indicate that they may have had wings in the past and they even had the ability of flight. Their theory further expounds that they may have flown to New Zealand from Madagascar and Australia. They have identified that this ability to fly has been lost three times independently. This, in turn, has led to the theory that the ability to fly may have been affected by a part of the bird's genome, which it could, ultimately, turn the gene that develops flight on and off. Without the need for flight (in New Zealand), it no longer required its wings and eventually evolved without them.