Satellite telemetry of King Eiders from northern Alaska 2002-2009

Keywords: Occurrence,King Eider,migratory connectivity,bird migration,Radio transmitters,Animal movements, Occurrence, Observation
Temporal coverage: 2002/2009

Original provider:
University of Alaska Fairbanks and U. S. Geological Survey

Dataset credits:
U.S. Geological Survey Outer Continental Shelf Program
U.S. Minerals Management Service
U.S. Geological Survey Alaska Cooperative Fish and Wildlife Research Unit
North Slope Borough
ConocoPhillips Alaska
Sea Duck Joint Venture
U.S. Fish and Wildlife Service
German Academic Exchange Service

Abstract:
King Eiders are large sea ducks that nest in Arctic ecosystems around the world and migrate and winter at sea. Since 2002, the University of Alaska Fairbanks has tracked the migration and movements of King Eiders from breeding grounds in northern Alaska. This dataset includes all the locations provided by satellite-tracked King Eiders between June 2002 and December 2008. King Eiders migrated from breeding grounds in northern Alaska to winter regions in the Bering Sea. Females returned to breeding grounds in Alaska, whereas males dispersed over 50% of the species global range in the summer after capture.

Purpose:
This study examined the migration routes and spatial distribution of King Eiders breeding in northern Alaska throughout the annual cycle. Satellite transmitters provided information on migration timing, migration distances, location of important molt, winter, and staging areas, migratory connectivity between those areas, and estimates of annual survival for adult and juvenile King Eiders.

Supplemental information:
The authors and field assistants captured adult and juvenile King Eiders with mist nets on breeding grounds in northern Alaska and equipped each bird with an implanted satellite transmitter (PTT 100, Microwave Telemetry Inc.). Satellite transmitters provided locations every 2-7 days for a time period of 10-20 months per individual. We used a filter program (PC-SAS Argos Filter v7.02, David Douglas, USGS Science Center) to remove implausible locations, and retained one location per duty cycle. The filter algorithm flags implausible locations based on two different filtering methods:

1. Minimum Redundant Distance (MRD): a user-defined distance threshold for determining locational redundancy; and
2. Distance, Angle and Rate (DAR): measurements that attempt to identify implausible locations based on the fact that most suspicious ARGOS locations cause an animal to incorrectly move a substantial distance and then return, resulting in a tracking-path that goes 'out-and-back' (and/or further validated by unrealistic movement rates, depending on the temporal frequency of the locations).

A hybridization of the MRD and DAR filtered results is used for the data in this dataset. The hybrid was specifically developed for avian tracking that includes relatively high-speed, directional, migratory events. Locations that passed the MRD filter are retained as ‘anchor points,’ then chronologically intervening DAR locations are evaluated to determine if they adhere to directional movement when compared to the vector formed by their preceding and subsequent MRD anchor locations.