There is actually a system to the four-letter codes, and while I still have some trouble with it, it helps if you understand how the code works (and if folks who want to abbreviate use it, instead of making up their own). The general rule is that you take the first two letters of the first word and the first two letters of the second word. HOuse FInch is HOFI. If the name has three words use the first letter of the first word, the first letter of the second word, and the first two letters of the third. Black-Billed MAgpie = BBMA. If the name has one word, use the first four letters of the word. OVENbird = OVEN. Now, even that can be a problem because while there are official common names, not everyone uses them or knows them. You would need to know that what we commonly call a Titmouse or a Tufted Titmouse is actually an Eastern Tufted Titmouse. ETTI. And then there are the overlaps. Cactus Wren and Canyon Wren. Well, memorize. CSWR and CNWR, respectively. Carolina Wren. CAWR. Then there were the days when I remembered the system but in a sleep-deprived stupor, applied it to the scientific names. And got a call from the principal investigator asking what kind of bird is a CACA? Any guesses? Ellen -- Ellen Paul Executive Director The Ornithological Council Mailto:epaul@dclink.com Ornithological Council Website: http://www.nmnh.si.edu/BIRDNET "Providing Scientific Information about Birds"