MDO: After browsing a little further into the USC tide predictor web page, at http://tbone.biol.sc.edu/tide/nph-tideshow.cgi , I found that I was a little hasty in my mathematical analysis. Colonial Beach, VA is almost straight across the Potomac from St. George's Island and gives a much more accurate projection of tide data than does DC. So, here are the new data: High Tide: Thu 1998-03-12 2:26 PM EST 1.60 (Patty's original sighting @3:45pm) High Tide: Sat 1998-03-14 3:36 PM EST 1.57 (VA group sighting @3:30pm) High Tide: Sun 1998-03-22 9:09 AM EST 1.59 (Leo Weigant sighting @10:00am) So, it looks like the high tides are when the bird has been seen, totally reversed from my earlier prognostication. Sorry about that! I didn't realize that there would be such a huge lag between DC and the lower Potomac. Below are the tides for the next several days in case anyone would like to have a shot at the loon. High Tide: Tue 1998-03-24 11:13 AM EST 1.68 Low Tide: Tue 1998-03-24 5:42 PM EST -0.01 High Tide: Tue 1998-03-24 11:42 PM EST 1.64 Low Tide: Wed 1998-03-25 6:05 AM EST -0.07 High Tide: Wed 1998-03-25 12:10 PM EST 1.75 Low Tide: Wed 1998-03-25 6:35 PM EST -0.11 High Tide: Thu 1998-03-26 12:38 AM EST 1.80 Low Tide: Thu 1998-03-26 7:02 AM EST -0.18 High Tide: Thu 1998-03-26 1:05 PM EST 1.82 Low Tide: Thu 1998-03-26 7:25 PM EST -0.21 High Tide: Fri 1998-03-27 1:31 AM EST 1.95 Low Tide: Fri 1998-03-27 7:55 AM EST -0.27 High Tide: Fri 1998-03-27 1:56 PM EST 1.87 Low Tide: Fri 1998-03-27 8:13 PM EST -0.29 High Tide: Sat 1998-03-28 2:21 AM EST 2.07 Low Tide: Sat 1998-03-28 8:47 AM EST -0.33 High Tide: Sat 1998-03-28 2:46 PM EST 1.89 Low Tide: Sat 1998-03-28 9:01 PM EST -0.34 High Tide: Sun 1998-03-29 3:11 AM EST 2.14 Low Tide: Sun 1998-03-29 9:38 AM EST -0.34 High Tide: Sun 1998-03-29 3:35 PM EST 1.87 Low Tide: Sun 1998-03-29 9:49 PM EST -0.33 High Tide: Mon 1998-03-30 4:01 AM EST 2.16 Low Tide: Mon 1998-03-30 10:29 AM EST -0.31 High Tide: Mon 1998-03-30 4:25 PM EST 1.83 -- Good Birding! ...and all this science, Tyler Bell I don't understand, It's mailto:bell@say.acnatsci.org just my job five days a week. California, MD Elton John (Rocket Man) http://www.anserc.org/