Saturday, February 9, 2013

Sexual Dimorphism

Merlin Falcon Male
 Sexual dimorphism is the term that is used to describe differences between males and females of the same species. Sexual dimorphism can manifest itself in several different ways. There can be differences in size, color, shape behavior or more. Reverse sexual dimorphism is when a species exhibits differences that are opposite of what we as humans consider the norm.
Merlin Falcon Female
 In the world of raptors the female of the species is larger then her male counterpart. Since in our world it is the male that is typically larger this is an example of reverse sexual dimorphism. It is hard to tell the difference in size from the pictures above but the female in the lower picture is larger. The merlin falcon, pictured above, is one of a small number of raptors that shows a form of sexual dimorphism. In the case of most raptors males and females have the same coloration. However in some of the smaller species the male is much more colorful then the female. This is not an uncommon trait with many different passerines (song birds) and ducks.  The reason for this is because the female needs to have some camouflage when she is sitting on the nest incubating eggs. Since the males job is not to incubate eggs but bring the female food he does not need the same camouflage. In larger raptors it is not necessary because there are few things that would mess with the nest of an eagle, red tail, great horned owl, or other larger raptor, but these smaller raptor, like the merlin, need to take care so that they do not become a meal for one of the larger raptors.



8 comments:

Lea said...

Beautiful photos and interesting information!
Have a wonderful day!
Lea
Lea's Menagerie

Martha said...

Beautiful! Info I did not know!!!

HansHB said...

Great photos!
Thank you for your information. I've learned some new english phrases...

??? said...

Gorgeous birds. Birds are the masters of sexual diphormism, I think. My favourite example are Eclectus parrots - for many years, no-one even realised that they were not two different species.

Gemma Wiseman said...

I did not know that one raptor would eat another! Interesting post!

Judith @ Lavender Cottage said...

Besides the good photos, interesting info shared.

Lighthousegal said...

Your photos are awesome and I love reading and learning about the birds.

Anni said...

Beautiful...and I learned a whole new terminology thanks to you this week.