Date: Fri, 14 Jun 2002 16:46:48 -0400 Reply-To: Maryland Birds & Birding Sender: Maryland Birds & Birding From: Walter Ellison Subject: Re: Atlas Question MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Hi Everybody, Paul Woodward asked: > I have a question about the philosophy of the atlas. Specifically, > why are blocks covered in their entirety if parts of them are in surrounding > states? Doesn't this mean that this is really a breeding bird atlas of > Maryland, DC and parts of Delaware, Pennsylvania, Virginia and West > Virginia? In an extreme case a species could be in the atlas even though it > didn't actually nest in Maryland or DC. These are excellent questions. Although I did not formulate this rule I believe I understand the rationale for the rule on covering state boundary blocks. The coverage rule is to allow valid comparisons among all blocks in the state and around its edges. All blocks should receive the same effort from block workers in spite of the artifice of human imposed boundaries. As many birders thankfully note, birds do not respect political boundaries. I'll give an example of what happens when partial coverage is the rule. A block with 25 square km of land in Maryland has 75 species and another along the W. Virginia line with 25 square km of land but only 12 square km in Maryland has 57 species but 75 in aggregate if the W. Virginia territory had been covered. Note how the results are biased against the partial block. We can do nothing about blocks that have more water than land, but the bias there is not created by an artificial political boundary but by a genuine ecological one. If a rare bird nested only in a neighboring state's portion of one or a few Atlas blocks this would be duly noted in the publication and the bird would not be "officially" added to the MD breeding bird list (although it would breed within MD's ecological purview). Good Atlasing, Walter Ellison MD/DC Atlas Coordinator - MOS 23460 Clarissa Rd Chestertown, MD 21620-3645 410-778-9568 rossgull@crosslink.net "A person who is looking for something doesn't travel very fast." - E. B. White ======================================================================= To leave the MDOsprey list, send e-mail to listserv@home.ease.lsoft.com with the following message in line 1: signoff mdosprey ======================================================================= =========================================================================