In order to determine the amount of food available for our 20 collared agoutis, we need a measure of Astrocaryum fruit abundance for each agouti territory. During the trapping, we tried to catch animals living in areas with either really high or very low food abundance. During the trapping period, we used Astocaryum abundance maps made from aerial photographs to determine where we would trap. Even though these maps give a very good approximation of the number of Astrocaryum trees per area, we needed a more accurate and direct measure. During April, we counted the amount of fruits and marked the location all the Astrocaryum trees in the 20 agouti territories. Amazingly, we were able to finish the mapping in less than 3 weeks. The result is that we caught some agoutis which live in territories with very low fruit abundance (Barry, Wilhelmina and Femke) and some which live in areas full of fruit (Pam and Fiona). Over all, the agoutis we captured live in a continuum of low vs. high fruit abundance, perfect for testing the fruit abundance hypothesis.
Twenty agouti home ranges. The pink circles represent Astrocaryum trees. The larger the circle, the more fruit in the tree. Note that some territories have very little fruit and some are almost completely filled with Astrocaryum trees.

April 30, 2009 at 14:59
WOW, I can’t believe how linear that graph is!
March 1, 2010 at 11:56
[...] in the home ranges of several radio-tagged agoutis that varied in how many palm trees they had. Some agoutis had home ranges full of fruits and seeds, others had almost nothing. The seed tags have small radio-transmitters that allowed us to find them when they moved. They [...]