EAC 8, Argo, January-March 1967
Page 10
Image from the Biodiversity Heritage Library. Contributed by Smithsonian Institution Archives. | www.biodiversitylibrary.org
Transcription
14°08'S along both the 126°W and 119°W meridians. This places them roughly 600+ miles east of the Marquesas where they nest. One of the most interesting aspects of this species' behavior at sea is its habit of "kicking off" of the water. A bird will fly along, low to the water, and then vigorously kick off a wave, causing the bird to fly parallel along the wave, similar to surfing. This action probably allows the bird to see small animals that are being carried along by the crest of the wave and then to feed on them. Not all of the storm petrels kicked off vigorously. At times they would only travel a few inches sidewards. Red-billed Tropicbird (Phaethon athereus) One individual of this species was seen on 27 January at 21°04'N- 118°54'W. Evidently they do not range far from the American coast. Red-tailed Tropicbird (Phaethon rubricauda) The distribution of this species (see figure 14) is very interesting. It appears to me that there were two distinct populations in the area - a northern and southern one with a hiatus of some 420 miles between them. Since Red-tailed Tropicbirds are not known to nest east of this area, the birds must have come from areas to the west. I suspect that the southern population came from French Polynesia and the northern one from the Hawaiian Islands. Twenty-nine birds were seen in the northern area of about 1,200 linear miles. In the Cromwell Grid, which was near Hawaii and twice as long, only two months out of 15 had higher totals, indicating that this Eastern Pacific Area had a higher density than the Central Pacific. Four out of the 29 birds, (13.8%) were positively first year birds. Four out of 16(25%) birds in the southern area were also in this age class. It is very likely that most, if not all, of these birds