The effects of methyl-mercury on spatial memory in zebra finches – Week 4-6

During these weeks of the summer, we finally began running trials on the sets of mercury and control birds designated for this experiment. My partner, Neil Huckstep, was out of town during these weeks, so another member of our lab, Capwell Taylor came in and helped me run trials. Essentially what we decided to do was to run trials in the morning and the afternoon in order to get through all the birds we needed to test this summer, and this proved to be very necessary. Otherwise, given how long it took for us to finish all trials using this plan, we would not have been able to finish in time if we just ran four birds a day. So it was very helpful to have Capwell fill in for Neil so we could run 8 birds a day instead of four. We started off by testing 8 mercury birds the first week and 6 the next week, which we later learned from my PI, might not have been the best idea. According to him, since conditions may change over the few weeks it takes to finish the control birds and move onto the mercury birds, it may have been better to do four control birds and four mercury birds each week to negate the possible effects of changing conditions. However, given the small sample size and the amount of time it took to finish the control birds, it’s likely that running all the control birds at once wasn’t problematic.

In these first two weeks, we had relatively few problems with all the trials themselves. We ran them all according to the protocol Neil and I had set out previously, and most of the birds were running through each phase of the experiment accordingly. The only issue we had in these first two weeks was the first failing bird we had to deal with. It had made it all the way to phase 3 of the experiment, which is the test of spatial memory, but it seemed to have established a strong preference for a certain corner of the cage in phase 2 of the experiment and wasn’t leaving that corner at all in any of the trials. Because of this, we decided to add an extra criteria for failing, which dealt with birds like this who wouldn’t even leave a certain corner in order to find where the food actually was. We decided to fail the bird out and wait to retest it at the end after all the other birds have been ran, in order to make sure its experiences from the first time it was tested wouldn’t affect it’s future performance.