Birder's Guide

NOV 2013

Birder's Guide is the American Birding Association's newest publication. Each issue focuses on a key subject, providing tips from experienced birders on a wide variety of topics like Travel, Listing & Taxonomy, Gear, and Conservation & Community.

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1986–1993). The New Mexico Thickbilled Parrot was seen by more than 500 birders, who asked the obvious question: Did the bird count? Following a near-unanimous rejection of the record by the New Mexico Bird Records Committee because of questionable provenance, the ABA CLC took up the matter. The CLC agreed with the decision of the New Mexico committee and voted not to "upgrade" the species' status, presumably to Code 5, "Accidental" (Pranty 2006, Pranty et al. 2006). The two of us do not see eye to eye on the countability of the New Mexico Thickbilled Parrot. Pranty's view is that the Thick-billed Parrot, being a Code 6 species, simply cannot be counted. Floyd sees the logic in Pranty's interpretation but also admits biological and probabilistic considerations: Could the bird, in fact, have been a naturally occurring vagrant? If so, and given that the species is already on the ABA Checklist, then Floyd would say that the bird counts on the lists of those birders who saw the bird and believe it was a naturally occurring vagrant. (Note that, despite our differing interpretations, the two of us are strongly allied in our conviction that it is highly worthwhile to document birds in the wild; we commend the discoverers of this bird, the many birders who studied and documented it, and the New Mexico Records Committee for its careful review of the record.) We have deliberately chosen to conclude our species accounts with an unresolved matter. Certain decisions of the ABA CLC and of other records committees are perforce complex and nuanced. They are open to interpretation and reevaluation. New technologies and new attitudes are upon us, and the CLC and other records committees will continue to adapt and evolve. Glossary Clustered. Gathered around a central point. In the case of parsimony analyses, various individuals are clustered together visually in a "tree", representing their apparent relatedness. Collecting. The practice of shooting birds with guns or trapping them in mist nets, skinning them, and placing the resulting study skins into a collection at a museum or university. Congener. A fellow member of a particular genus. Chipping Sparrow is in the same genus as Clay-colored Sparrow. They are congeners (noun) and congeneric (adjective). Emarginated. The outermost primaries of some birds feature a noticeable, gradual narrowing along the leading edge toward the tip. This narrowing is called emargination, and the feathers are referred to as being emarginated. This feature varies from species to species and can, in some cases, be helpful in identifcation. Extinct. No longer in existence anywhere; no living member of the species exists (e.g., Passenger Pigeon and Tyrannosaurus rex are both extinct). Extirpated. No longer occurring in a particular location but still existing elsewhere (i.e., not extinct). (e.g., Greater PrairieChicken has been extirpated from Canada and most of the eastern U.S.) Exotic. A noun or adjective describing a bird occurring outside its natural geographic range as a result of human transport. Some species were deliberately released while others escaped accidentally. The latter are called escapees. Mitochondrial DNA. DNA that is found in a part of the cell called the mitochodrion. In most species (including humans and birds), mitochondria (plural) are inherited solely from the mother, so mitochondrial DNA tells us about an organism's maternal lineage. Parsimony analysis. Data analysis that uses the principle that the simplest explanation is the one that is preferred. In the analysis of phylogeny, parsimony means that the hypothesis of relationships that requires the smallest number of character changes is most likely to be correct. In molecular systematics, these character changes are often DNA mutations. Pinioned. Describes a bird rendered permanently fightless by amputation of part of the wing. Sensu lato. Latin for "in the wider sense". Sensu stricto. Latin for "in the stricter sense". Species-pair. A pair of species, often each other's closest relatives. Spotted and Eastern towhees form a species-pair. Sometimes species within a pair are diffcult to distinguish; unidentifable individuals may be referred to using both names (e.g., Pacifc-slope/Cordilleran Flycatcher, Hawaiian/Galápagos Petrel). Spectrogram. A graph that shows a visual representation of sound, usually with the y-axis representing frequency and the x-axis representing duration. Split. When scientists decide that a taxon (often, a species) is really two or more taxa, the resulting action is called a split. Also used as a verb (e.g., Rufous-sided Towhee was split into Eastern Towhee and Spotted Towhee). Stable isotope analysis. A scientifc procedure that looks at the proportions of certain kinds of atoms within a sample. This analysis is often used with feathers to give a general idea of where the bird was geographically while it was growing that feather. Vagrant. A bird occurring far outside its normal geographic range, without direct human assistance. Web-Only Content and References Be sure to go online for expanded web-only content on this topic. In particular, the authors examine the growth of the ABA Checklist over the years, and analyze past predictions made about which species would be added. (Those predictions weren't the best, in many cases!) You will also fnd the list of works referenced in this article. November 2013 | Birder's Guide to Listing & Taxonomy 49

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