Birds Are Ideal Models For Studying Speciation Because of Their Wide Range of Traits And
Accompanying Spatial Patterns. For Centuries, Morphological Procedures Were the Preferred Method For
Determining the Degree of Relatedness Between Species and Intraspecific Variation, Until Molecular
Genetic Investigations Gravely Questioned Traditional Morphology-Based Results. However, With The
Advancement of Multivariate Statistics and the Ease With Which Morphological, Phylogenetic, And
Ecological Information Can Be Combined, Morphology Is Being Reconsidered As a Valuable Tool For
Ornithological Research. This Chapter Examines the Most Essential Features of Morphological Variation In
Birds, Including How to Assess Its Plasticity and How Phenotypic Variation Can Be Included into a Larger
Evolutionary Framework That Explains Avian Body Alterations In Light of Speciation Events.