Organisms are capable to perfectly adapt to their environment. In particular, bird beaks can be precisely shaped by natural selection to deal with certain types of food. However, such "fine-tuning" should be inevitably associated with narrowing and canalization of morphological variation, and hence limit the potential for future adaptation if environmental conditions change. Yet, organisms are clearly built in such a way as to resolve this tension - precise adaptation and astonishing diversification routinely coexist in the same trait. For my postdoctoral research at the University of Arizona, I studied the mechanisms of beak evolution in the house finch. This species has recently colonized northern parts of the United States, and this rapid range expansion was associated with intriguing evolution of the beak morphology: nearby populations can be distinct in the beak size as well as distant populations can have identical beak parameters.