Second North American Sea Duck Conference - Patuxent Wildlife ...

SECOND NORTH AMERICAN SEA DUCK CONFERENCE
DEVELOPMENT OF METHODOLOGY
FOR CAPTURING MOLTING SURF SCOTERS
Scott Gilliland, Andre Breault, Guss Dicker, Keith McAloney, Eric Reed and Pierre Ryan
Canadian Wildlife Service; Scott.gilliland@ec.gc.ca
The surf scoter (Melanitta perspicillata) is one of the least studied ducks in North America. Within
the last 10 years, we have located their principal molting areas along the coast of Labrador, Canada,
and in 2004, we initiated a molting ecology study of surf scoters. During the first field season, our
primary goal was to develop capture techniques. Herein, we describe the capture technique and
preliminary results. Our study area was located within three large archipelagos near Nain, Labrador
where 10-15,000 birds were known to molt. We refined techniques used for drive-trapping birds for
use in open, deep-water areas. Flocks were first located by patrolling the coastline from 5-6 m skiffs.
Once located, the flock was herded towards shore using two boats, while a third boat set a gill net in
front of the flock. Nets were set perpendicular to the shore, and curved back towards the flock. All
nets had 90 mm mesh size and were 4 m deep. We tested nets varying in length from 180 to 365 m.
The ends of the net were marked with single scoter decoys and strings of decoys were attached to the
nets’ float-line about a third the length of the net from the near shore end. Once the net was deployed
the third boat joined the drive and the birds were herded towards the net. When the flock was 2-5 m
from the net we forced them to dive by firing 1-3 cracker shells over the birds. Birds were also hazed
into the net using air horns. From 8 to 17 August, we made 29 sets and caught 661 birds (mean ±
sd bird caught per set was 22.8 ± 15.6). The overall species composition was 95.6% surf scoter,
3% white-winged scoter (Melanitta fusca), 1.5% common eider (Somateria mollissima) and