Classification 2: Empidonax Flycatchers

This closely related group of songbirds was chosen for their similarity in vocalization as well as the fact that they are visually identical and can only be positively identified by their vocalizations. Examples of the frequency spectra of four of these flycatchers are shown in the following figure. The training and testing sets used were based on the mating vocalizations of the species. These songs were the most complex. The output axon of the basic network described in the House and Purple Finch section was expanded to four neurons to allow four classifications. This network correctly categorized the calls the majority of test cases. It was possible to make the network fail by introducing an unfamiliar vocalization of one of the target species although in twenty percent of cases, the unknown vocalization was correctly classified.