Time for Some New Field Guides “Gonna rise up, find my direction magnetically” - Eddie Vedder

The relatively new study of genetic sequencing has provided a methodology to reevaluate the tree of life. Traditionally, the tree of life was based on morphological comparisons between animals, combined with the study of fossils. This was done with the understanding that evolution can perform morphological tricks, making distantly related animals appear much closer, since natural selection often forces similar adaptations in comparable environments. This is known as convergent evolution. It has been thought that the osprey, for example, although superficially similar to the hawks, and lumped with them in the field guides, is a product of convergent evolution, and not really a hawk at all. Genetic sequencing has changed our understanding of evolutionary patterns. Initially, researchers proceeded by comparing a select few genes on a specific chromosome to determine degrees of relatedness among species. This often yielded inconclusive or contradictory results. Better analysis tools have been developed to facilitate comparisons of relatively large sequences, consisting of thousands of DNA bases, producing a more robust result with much smaller error bars. This rapidly developing science is known as phylogenetics, and it has been recently focused on birds. In the June 27, 2008, issue of Science, Hackett, et al., published their study of the relationships between 169 species of birds. The results demonstrated some expected relationships, verifying the old comparative methods, but also revealed some surprises. The passerines, or perching birds, make up half of all bird species and include such large, diverse groups as the warblers, blackbirds, and finches. They were found to be closely allied with the parrots, which was quite unexpected. Also closely related to the passerines and the parrots are the falcons. A second group of “cousins” to the aforementioned birds includes the woodpeckers, kingfishers, owls and hawks. And yes, the osprey is allied with the accipiters, or bird hawks. Next in the relatedness hierarchy are the shorebirds, which was also somewhat unexpected. Continuing down towards the most “primitive” or oldest orders, we find the herons along with most of the other wading birds. Also in this group are the loons. This verified another recent genetic analysis which dispelled the long-held belief that loons were the most primitive living birds, which is why they appear first in traditional field guides. The rails and cuckoos turn out to be close family members, not too distant from the loons. Finally, the waterfowl, including our swans, geese, and ducks, are now believed to be the oldest and most primitive birds, backing up some recent fossil evidence uncovered in China. This, of course, will be a boon to the publishers of field guides, and I will be among the first of the suckers to buy them.