I'm currrently developing a project comparing female-female and male-male aggression using the house wren population at the Kellogg Biological Station.
Aggression has classically been
considered a male phenomenon. Most of the theoretical work on
within-sex aggression has utilized male examples, which poses no
problem if female-female aggression is the same but may miss important
nuances if the sexes differ. Despite this historical bias,
female-female aggression is a widespread phenomenon in many “normal”
species. Furthermore, recent work suggests that female-female
aggression may be relatively more sensitive to the value of the
contested resource. The reason behind this difference, however, is
unclear. While many of the evolutionary factors underlying aggression
are the same for both sexes, the costs to losing a fight can be very
different for males and females. House wrens can be polygynous, meaning
that a male will sometimes have more than one female on his territory.
If a female loses an aggressive encounter, she either has to share her
male with another female or settle as a secondary female on another
territory. If a male loses a fight, he will be kicked off his territory
and is unlikely to gain a territory elsewhere. Because of this high
cost, males should be heavily motivated to fight hard, even if
defending a poor quality territory. Females, however, should be more
likely to modulate their aggression in response to the quality of the
resource they’re defending. I will be
testing whether these differences in costs make female-female house
wren aggression more responsive to resource value than male-male house
During the summer of 2009, I worked as an NSF
funded REU at the Cary Institute of Ecosystem Studies alongside Dr.
Kara Belinsky and Dr. Ken Schmidt. I worked with the veery (Cartharus fuscescens),
a migratory song bird with an acoustically complex song (see
above). Using a robotic veery and playback, we investigated
whether vocal signals predicted
aggressive actions in territorial males. Our results suggest that
songs lacking introductions signal descalation and that songs and
"whisper calls" signal escalation.