8 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 123 



Codes for species identification and number reliability, direction of 

 bird movement, behavior, marking, and other sighting fields are given 

 in table 2. Reliability was determined and recorded by the observer 

 in his at-sea notes. Some of the at-sea logs recorded doubtful identifi- 

 cations of dark shearwaters as "sooty-slender-bill" with a notation 

 that the underwings appeared light. Such sightings were coded as 

 "sooty shearwaters," 122519, in the species identification field (29-34), 

 as "either this or the next most similar form," 2, in the species relia- 

 bility field (36) and as [consult] "identification" [data in at-sea log], 

 1, in the special information field (54). The next similar species to the 

 sooty shearwater in the central Pacific is the slender-billed shear- 

 water, but in the southern Atlantic Ocean it might be the great- winged 

 petrel, Pterodroma macroptera. 



Special means of marking birds to show points of origin or other 

 status were employed in studies of seabirds in the central Pacific 

 Ocean. Birds marked by "painting" with body dye or by attaching 

 leg bands and colored plastic streamers were expressed in code in 

 the system. Colors were used for identification of birds at a distance 

 when they could not be captured. In seabirds, color or plumage 

 phases may indicate geographic origin or reproductive condition. 

 Light and dark color phases in petrels, boobies, and jaegers may 

 vary in relative proportions in different geographic populations. 

 A pinkish or yellowish tinge in white tropicbird, gull, or tern plumage 

 may indicate reproductive activity. 



The special weather conditions field was used to refer to squalls, 

 storms, or calms that were so local they could not be expressed in 

 the environment deck. The special information column was used as 

 a warning signal to alert the scientist to consult the raw data for a 

 particular field in the observer's at-sea log. A routine sighting as a 

 bird crossed the ship's bow was considered arbitrarily to have a 

 duration of one minute. Birds following in the wake were counted 

 periodically, and an attempt was made to determine duration of their 

 association with the ship. Direction of ship movement and wind 

 and wave directions on the environment card were recorded as the 

 first two digits of the compass heading rounded off to the nearest 

 10 degrees (e.g., 165°= 17, 24°=02). A stationary ship or calm air 

 or sea was coded 00. 



Part of a page of an at-sea observation log and its numerically 

 coded translation onto the intermediate coded sighting sheet is shown 

 ready for punching into cards in figure 4. 



Environment deck. — The format of the environment card was 

 slightly modified from cards already in use by the Bureau of Com- 

 mercial Fisheries in the Hawaii area. Complete environmental data 

 of this sort are recorded on standard forms and punched into cards 



