When Sexual Dichromatism isn't so Binary

In birds, males are colorful and females are not, right?

Not always. 

Some females find themselves with pigments in their feathers that weren't really meant to be there. What comes from this is irregular feather structure due to different growth patterns, different barb size, etc. There is a variety of reasons why this may happen, the most probable of which being that the female has a hormonal imbalance. Most of the time these anomalies are just a bit of brown on the tip of the rump feathers. However, more rare are the females that develop male signaling colors such as reds and the variant yellow.

The way in which these females' feathers develop suggests a stress response; males with the same pigments' feathers are generally symmetrical and "prepared" for these kinds of pigments. What is different in feather development between females and males such that males are prepared for these pigments while females are not? I hope to answer this and related questions in the coming months. 

Feather Masses

"Light as a feather".

 At this point, I know that phrase all too well. This past week, I was trained in a new procedure which allows us to find the portion of each feather which is pigmented. First, we weigh the whole feather. Then we weigh the pigmented section. Sounds easy enough, right? I thought so at first.

Our study is concerning the pigmentation of house finch feathers. This is what a house finch looks like:

For some perspective on their size, this is someone holding a house finch and one of their feathers:

So you see, it's not all too difficult. In the lab, all we have to do is use tiny forceps and tiny scissors to cut the red tips of the feathers from the rest of them. I have become remarkably good at holding my breath. As my adviser said when he saw me working on this process: "Don't sneeze". I've made the mistake of breathing too hard; I was crawling on the ground for hours searching for crown feathers which couldn't have been more than a few millimeters long.

As I start this task which already has taught me so much patience, I'm also given the opportunity to see how my work is helping. The post-doc that all my work has been helping the past few weeks is presenting her findings tomorrow. I love being able to contribute; I would gladly hold my breath to help anyone I've met in my lab.

Thanks for reading, guys.

Caitlin