Burke Museum - 3 - Sex

Lat:47.66063861939029, Lon:-122.31028240171611
Day, 2012
4/26/12
1:30-3:30

The section on sex was the most interesting to me. Rob Faucett taught us about all the different characteristics of a variety of birds that differ in males and females and why they differ. For example, most birds are sexually dimorphic; males are more colorful and bigger while females are more dull and smaller. While being big and colorful isn’t the best for survival, the males usually need to be in order to attract a female and reproduce. Rob said that sometimes the females will actually be the bigger and more colorful if the males will be doing most of the parental caring. These are called “polyandrous” birds (when the common pattern of sexual dimorphism is reversed). An example of a polyandrous bird is the Jesus Christ bird. (It’s called this because it “walks on [stuff on the] water”.” The female Jesus Christ bird actually has claws under her wings for fighting other females. They fight for territory and to attract males.

Another thing we talked about was sperm competition and mating patterns. This bit was interesting because if a male bird has smaller testes, it is not a very big competitor for females; whereas if it has larger testes, it is very competitive. An example of mating patterns was the fairy wren. This bird is bright blue with black streaks. Females prefer to mate with the bluest and most mature males. This is because the bluest and most mature males theoretically have the “best” genes. This is seen in many other species as well.

Another interesting thing about this section was that tropical birds have virtually no difference in appearance. This is because both the male and female share the responsibility of caring for their young. I thought it was cool how these birds actually form pair bonds and the longer they stay together, the more successful they are. It seems that not a whole lot of species that we’ve been learning about form pair bonds and share caring for their young so I guess that’s just nice to know.

Species List:
Pheasants
Jesus Christ bird
Fairy wrens
Wood duck

Posted on June 1, 2012 05:15 AM by lisad22