There is also proof that multiple hybrid zones are present in the United States, meaning that different environments played a major role on how the Northern Flicker evolved (Grudzien, Moore, Cook, and Tagle). This is thought to be the case due to natural selection (Moore, Graham, and Price). In a southwestern hybrid zone, Northern Flickers actually have different mtDNA patterns. To be considered a hybrid zone, the Northern Flickers in that particular region must have been absolutely isolated before hybridization occurred (Moore and Buchanan). These hybrid zones are defined as a certain area where mating has led to a variation of different genes in Northern Flickers (Moore and Price). Although they are different colors, more than 90% of modern day Northern Flickers in the North American curve are said to be hybrids of an older species similar to Northern Flickers (Short). Red-shafted Northern Flickers are found in the west while yellow shafted Northern Flickers are found in the East. They are a little under a foot long with either a yellow shaft or a red shaft depending on their geographic location (US Geological Survey). The Northern Flicker ( Colaptes auratus) is a woodpecker that is commonly found in both the Eastern and Western United States, as well as Canada. Content for this page researched and created by Carly Duncan.