Date: Sun, 20 Feb 2000 22:14:58 -0500 Reply-To: Maryland Birds & Birding Sender: Maryland Birds & Birding From: Phil Davis Subject: Re: Tufted Duck [and Ruddy Shelduck] Comments: To: bteetz@home.com In-Reply-To: <000001bf7bdd$6f79b7e0$1fad0718@dlcty1.va.home.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed At 03:02 PM 02/20/2000 -0500, Bill Teetz wrote: (SNIP) >I am rather new to listing, etc., but I have a question that some may >consider off topic. Why is the Tufted Duck considered a sighting and the >Ruddy Shelduck that some have seen at Hains Point thought to be an escapee >since both are listed as Eurasian Species (at least in my Peterson's?) Bill - This is a good question and this will probably generate a good deal of follow-on discussion. First compare the ranges of the two ducks and patterns of vagrancy ... Tufted Ducks (_Aythya fuligula_) breed from Iceland east through Scandinavia and Siberia (Russia) and as far east as the Commander Islands (about 230 miles from Attu, Alaska). They migrate regularly into southern Alaska. They also migrate irregularly down the Pacific Coast as far as southern California and rarely inland into the states. In our hemisphere in the winter, they are found in Greenland, along the New England and Mid-Atlantic coasts, and in Bermuda. Inland, records come from the Great Lakes and southern Canada. In the western hemisphere, they are found in migration in Southern Africa, the Indian Ocean, and Micronesia. They, therefore, seem to be quite cosmopolitan and records in the mid-Atlantic are certainly not unexpected. Some sighting could always be escapes from private waterfowl collections, and any signs of captivity (bands, clipped toes, certain behaviors, etc.) would certainly be considered by local records committees. Ruddy Shelducks ( _Tadorna ferruginea_), on the other hand, have a more limited breeding range ... from southeastern Europe eastward to Turkey, central Asia, to Mongolia. They also have a more compressed range of migration, staying pretty much in the same longitudes ... northern Africa, western Mediterranean, Arabian Gulf, Turkey, India/Pakistan, and to eastern China. Now, the "analysis" ... In general, longer distance migrants (such as Tufted Ducks) tend to be found "out of range" and become vagrants more often. The AOU, from whom we rely on for our taxonomy standards, recognizes the Tufted Duck on the AOU Check-list, while the Ruddy Shelduck is contained in "Appendix 1" of the Check-list, meaning there are North American records, but the "natural occurrence ... of the species is disputed". While there are sightings of these ducks in North America, the AOU presumes they are escapes. The only accepted "natural" records of Ruddy Shelducks in our hemisphere are from western Greenland. I think that all of these factors go into the general thinking that the Tufted Duck is "probably" (at least from a percentage standpoint) a natural vagrant, while the Ruddy Shelduck is likely an escapee. I think we should keep track of these Shelduck sightings, since the AOU does reference such reports in its Check-list. Hope this helps ... Phil ================================== Phil Davis Davidsonville, Maryland USA mailto:PDavis@ix.netcom.com ================================== ======================================================================= To leave the MDOsprey list, send e-mail to listserv@home.ease.lsoft.com with the following message in line 1: signoff mdosprey ======================================================================= =========================================================================