Aaron's project: What's in an egg?

 My name is Aaron Aguirre and I am an undergraduate at Michigan State University studying Fisheries and Wildlife. This summer I was lucky enough to be Cara’s assistant as she conducted her research.

As part of helping Cara with her work, I was also responsible for developing my own topic of study and designing an experiment to conduct throughout my time here. Delving away from bird songs and calls, I decided to put more of a focus on the other ways in which house wrens communicate with each other.  Something Cara had said to me sparked my curiosity in the eggs of these birds. She told me that the last egg of a female’s clutch will often be much lighter than the others because male house wrens seem to be attracted to lighter eggs and more willing to invest in caring for them. After collaborating with Cara I decided to study if the brightness of a female’s eggs relates to their physical condition as well as if stress on the females will affect the brightness of their eggs. 

 Above: An example of the photos Aaron used to collect data on eggs.  As you can see above, the last egg is often brighter than the ones before.  A previous graduate student in the Getty lab, Lindsay Walters, studied the connection between egg color and male investment.


My interest in this topic stems in a similar way from why Cara is studying house wrens. When people think “bird communication,” they will probably think about the multitude of bird songs and calls they hear in the early morning. Similarly, most will think that male song birds are the gender that are competing and proving themselves to the females; a nice song tells the female that a male is in high condition worthy of being their mating partner. This is why I find my topic to be so interesting; it is the unexpected. By looking at the eggs, I am seeing how females are communicating to the males and how they show males that they are physically fit and worth investing time and energy into ensuring the success of their offspring.