Undergraduate Honors Thesis Projects

Date of Award


Document Type

Honors Paper

Degree Name

Zoo and Conservation Science-BS


Biology & Earth Science


Anna Young, PhD

First Committee Member

Joan Esson, PhD

Second Committee Member

John Tansey, PhD


Poicephalus, parrot, morphology, color, taxonomy

Subject Categories

Other Animal Sciences | Zoology


Though describing and delimiting species is one of the principle aspects of many disciplines within biology, there is often debate about which methods and concepts should be used to make such decisions. The Tobias criteria for quantitative species delimitation represent one attempt to create a standard method of delimiting species based on the morphological species concept. However, previous examples of using these criteria have not always been completely quantitative. This study uses quantitative morphological and color data of three Poicephalusparrots as a case study for the effectiveness of the Tobias criteria. The results show varying levels of support for and dissent against previous species decisions made regarding these parrots, and may provide support for rethinking these past delimitations as well as working towards multifaceted, quantitative decision-making for future species.