EAC 26, Jordan, October-December 1967
Page 97
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Transcription
suggests that low numbers may be found north of the southern boundary of the North Equatorial Countercurrent, and very few to the south. Harcourt's were also very scarce within 400 miles of the coast. Leach's Storm Petrel (Oceanodroma leucorhoa) 1 collected This was the most widely distributed species on the cruise; they were seen commonly in virtually all areas except close to shore. The white-rumped forms were the only color phase throughout the cruise except near Guadalupe Island where dark-rumped forms were seen regularly. The distribution of Leach's was irregular although widespread. Gen- erally it was suspected that over most of the survey the birds were residents. However, between 15° and 25° North on the western track there was some suggestion that many of the sightings were of migrants. Small flocks were seen frequently, and there was also slight suggestion of a southeasterly movement. Galapagos Storm Petrel (Oceanodroma tethys) This was the most easily identified white-rumped storm petrel seen on the cruise. Thus it is felt that most which were seen were recorded to species and that few of those birds recorded as "white-rumped storm petrels" were of this species. The distribution of O. tethys appeared to be restricted to areas near the Galapagos Islands; only a few were seen more than 500 miles to the west. Although crude allowances were made, it is possible that the densities recorded in tables of this report may be somewhat inaccurate as it was not possible to determine how long individuals followed the ship. Regardless, the observations did indicate that the species was more common to the west than to the northwest or southwest of the breeding islands. Black Storm Petrel (Loomelania melania) During October-November this was found to be a coastal species within the cruise area. All sightings were south of central Baja Peninsula. Least Storm Petrel (Halocyptena microsoma) What few birds were seen were within the range of the Black Storm Petrel. Loon (Gavia sp.) A single unidentified loon was seen off Northern Baja on 2 December; it was being harassed by a Pale-footed Shearwater. Brown Pelican (Pelicanus occidentalis) This species was seen only off Northern Baja and in the harbour at Manzanillo.