Begging Behavior in Zebra Finches

This summer, I will be studying differences in begging behavior in a model bird species, the zebra finch, to determine if dietary methyl mercury changes behavior. In this experiment, 10 breeding pairs will be fed a diet homogenized with 1.2 ppm of mercury and will be compared to 10 breeding pairs fed a control diet. This low level is environmentally relevant. The pairs will be allowed to breed and nest boxes will be affixed with CCTV cameras and microphones in order to record the calling and behavior of hatchlings. Amplitude, frequency, and active begging (such as craning neck backwards with gaping mouth) will be compared between the experimental groups. The data will shed light on if methyl mercury changes behavior in the nestling, which could impact them later on.

 

Currently, I am working on analyzing growth trajectories of control and mercury-fed birds and have found a significant difference in the masses. Mercury-fed birds tend to be significantly heavier throughout the course of their life with the gap growing at day five post-hatch. By viewing the birds during this time frame, I will be able to determine whether it is because they are begging more and receiving more food from their parent or if it is due to the way mercury is metabolized.

 

This research is important because levels of mercury are accumulating in our ecosystems. Avian systems in particular have shown poorer growth, immune system response, and organ function as a result of exposure to methyl mercury (Boening 1999). Mercury is also making its way into the diet of humans. As it is a known stressor, its effects must be further researched in order to better understand the possible consequences organisms will face. Research showing the negative effects helps to advise companies on reducing pollutants and cleaning polluted spills. Our lab has previously found that mercury changes the behavior of birds by increasing stress hormones. These stress hormones change both the growth trajectory of the nestling and the parental investment.