Recognizing the limits of species is one of the great challenges of biology.\u00a0 Some species are remarkably variable; humans with our ranges of skin color provide a nice example.\u00a0 On the other hand, some separate species can scarcely be separated based on their morphology.\u00a0 The Willow Flycatcher and Alder Flycatcher are dead ringers for each other yet the distinctive songs of the males ensure that only Willow females will mate with Willow males and Alder females with Alder males.<\/p>\n
A branch of biology called sytematics is devoted to identifying the limits of species and to understanding the relationship among the species.\u00a0 We still follow the basic classification scheme erected by Charles Linnaeus nearly 300 years ago.\u00a0 Closely related species are placed in the same genus.\u00a0 Closely related genera are placed in the same family and so on upward in the scheme to orders, classes and phyla.<\/p>\n
Systematic classifications were initially based on the structure of organisms.\u00a0 Over the years, systematists have used other traits to help understand species limits and interrelationships.\u00a0 Behavior can be an informative trait.\u00a0 The ability to interbreed is used by some systematists as an indication of a \u201cgood\u201d species.\u00a0 In the past few decades, comparisons of DNA has greatly clarified and refined our understanding of the relatedness of various groups of organisms.<\/p>\n
Like any scientist, a systematist regards her understanding of the relationships of a particular group of organisms (like the shorebirds, for instance) as a working hypothesis.\u00a0 The hypothesis is provisionally regarded as true but needs continued testing.\u00a0 As our knowledge grows, hypotheses have to be rejected.\u00a0 Like any science, systematics is a dynamic field.<\/p>\n
A nice example of our changing understanding is the Yellow-rumped Warbler.\u00a0 Western birds have yellow throats while eastern birds have white throats.\u00a0 These birds were initially treated as separate species.\u00a0 The Black-fronted Warbler in Mexico and Goldman\u2019s Warbler in Guatemala, similar to Myrtle Warbler and Audubon Warbler, also were described as distinct species.\u00a0 However, all of these four species based on additional systematics work were combined into the\u00a0 Yellow-rumped Warbler in 1973.\u00a0 It\u2019s possible that some or all of these forms will be split back into separate species in the future.<\/p>\n
To keep track of these taxonomic changes for birds, the American Ornithologists Union erected a Check-list Committee.\u00a0 This committee is charged with producing the Check-list of North American birds, the official source on the taxonomic classification of birds of North and Middle America.\u00a0 The current version is the seventh, published in 1998.\u00a0 You can see the check-list on line at http:\/\/www.aou.org\/checklist\/north\/print.php<\/a><\/p>\n The committee monitors the publications on bird systematics and revises the check-list if necessary.\u00a0 The committee usually publishes a supplement in the ornithological journal, the Auk, every July to describe any changes to official Check-list.<\/p>\n Most of the changes in the 2013 supplement pertain to birds of Middle America so I will not cover them here.\u00a0 The supplement does describe some taxonomic changes to some shorebirds: Surfbird, Buff-breasted Sandpiper, Spoon-billed Sandpiper, Broad-billed Sandpiper.\u00a0 The Buff-breasted is a regular passage migrant in Maine and Ruff is an occasional vagrant.\u00a0 Each of these species was formerly placed in its own unique genus.\u00a0 Recent systematics work has shown these species are not sufficiently different from other shorebirds to merit their own genus.\u00a0\u00a0 Each of these five genera has now been eliminated and all five species are now placed in the genus Calidris<\/i>, the genus that includes a number of shorebirds including Sanderling, Semipalmated Sandpiper, Red Knot and Dunlin.\u00a0 If you are a stickler for the scientific names of birds, make those changes in your field guide.<\/p>\n The other change may affect your life list if you have birded in the West.\u00a0 The Sage Sparrow has been split into the northern Sagebrush Sparrow and the southern, Californian Bell\u2019s Sparrow.<\/p>\n [First published on September 1, 2013]<\/p>\n\n Recognizing the limits of species is one of the great challenges of biology.\u00a0 Some species are remarkably variable; humans with our ranges of skin color provide a nice example.\u00a0 On the other hand, some separate species can scarcely be separated based on their morphology.\u00a0 The Willow Flycatcher and Alder Flycatcher are dead ringers for each […]<\/p>\n","protected":false},"author":146,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_s2mail":"yes","ngg_post_thumbnail":0,"footnotes":""},"categories":[1281,4623],"tags":[],"builder_content":"","_links":{"self":[{"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/posts\/616"}],"collection":[{"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/users\/146"}],"replies":[{"embeddable":true,"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/comments?post=616"}],"version-history":[{"count":1,"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/posts\/616\/revisions"}],"predecessor-version":[{"id":617,"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/posts\/616\/revisions\/617"}],"wp:attachment":[{"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/media?parent=616"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/categories?post=616"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/tags?post=616"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}