Tern Island Albatrosses - 1998
Wake Forest University

National Science Foundation

Satellite telemetry was used to identify the foraging distributions of two congeneric species of albatrosses that nest in the tropics/subtropics. Breeding Black-footed albatross (Phoebastria nigripes) and Laysan albatross (Phoebastria immutabilis) nesting in Tern Island (Northwest Hawaiian Islands) and tracked during the 1998 breeding season (January - June) performed foraging trips to continental shelves off North America. Black-footed albatross made long trips to the west coast of North America (British Columbia to California). Laysan albatross traveled primarily to the north of the Hawaiian Islands, and reached the waters of the Aleutian Islands and the Gulf of Alaska. These albatross species mixed short and long trips during the chick-rearing period (February - June), but engaged in short foraging trips during the brooding period (within 18 days after chick hatched, January - February).

The analysis of albatross movement patterns showed that the core feeding areas during long trips were located over the continental shelves of North America, from California to the Aleutians. An understanding on the foraging biology of North Pacific albatrosses has important implications for assessing their bycatch risk in commercial fisheries.



We thank C. Alexander, L. Carsten, P. Fernández, F. Juola, P. Sievert, A. Viggiano and S. Wang for assistance in the field, and the United States Fish and Wildlife Service for logistical support. This research was funded by National Science Foundation grant DEB 9629539 to D. Anderson.

These albatross were tracked using PTT-100 Argos transmitters (Microwave Telemetry, Columbia, MD) operating at a 90-second repetition rate and programmed to operate on a 8:24 h ON:OFF duty cycle. Transmitter bench-tests before deployment revealed that the Argos location quality classes (lcs) had the following median position errors, expressed in kilometers: lc B (24.23), lc A (2.95), lc 0 (5.65), lc 1 (1.53), lc 2 (0.73), and lc 3 (0.44).



The low-quality class B locations were discarded because they misrepresented the telemetry tracks. Thus, this dataset includes 3505 high-quality locations (lc classes A or better) with median positional errors <6 km.

Overview

Attributes described below represent those in the original dataset provided by the provider.
Only minimum required attributes are visible and downlodable online. Other attributes may be obtained upon provider's permission unless otherwise noted below.

Attributes in dataset provided

Attribute (table column)	Description
record_number	definition not provided
trip_number	definition not provided
bird_number	definition not provided
species	Species name recorded
day	Day
month	Month
year	Year
hours_gmt	Hours in GMT
minutes_gmt	Minutes in GMT
seconds_gmt	Seconds in GMT
argos_quality	Quality of Argos data
latitude	Latitude in decimal degrees
longitude	Longitude in decimal degrees
geom	Geometry field added by OBIS-SEAMAP
oid	Unique ID number (generated by OBIS-SEAMAP)