SURGERY
PERFORMED TO INSTRUMENT
SURF AND BLACK SCOTERS FOR SATELLITE TELEMETRY |
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Satellite telemetry is being used in the
Atlantic Seaduck Project to learn more about the breeding
and molting areas of scoters in northern Canada.
Scoters were captured on wintering grounds of
Chesapeake Bay, Maryland, USA and migrational staging areas
on the Restigouche River, New Brunswick, Canada.
Scoters captured in the Chesapeake Bay were
transported in small plastic animal transport crates to the
veterinary hospital at the USGS-Patuxent Wildlife Research
Center, Laurel, MD, USA.
Ducks caught in New Brunswick were transported in the
same type of animal transport crates to a local veterinary
clinic for surgery.
A PTT100 transmitter manufactured by
Microwave Telemetry, Inc. (Columbia, MD, USA) was
surgically implanted in the duck's abdominal cavity
following general anesthesia using isoflurane (Isoflo,
Abbott Laboratories, North Chicago, IL, USA) for both
induction and maintenance.
Transmitters measured approximately 5 x 3.8 x 0.6
cm and have a nominal weight of 39 grams. This weight is
slightly heavier than normal because of potting required
to allow the transmitters to withstand pressures
accompanying diving to depths of 30 m.
The transmitter's 20 cm antenna exited the skin
lateral to the sacral vertebrae.
Because of recent problems with extrusion of
cylindrically-shaped implant transmitters through
the antenna perforation, transmitters used in this
study were wide-bodied with no abrupt edges.
Initially, ducks were given butorphenol
tartrate (Torbugesic, Fort Dodge Animal Health, Fort
Dodge, IA, USA) as an analgesic.
However, this was stopped when we observed
that the analgesic made the ducks lethargic and
slowed the preening process post surgery.
Ducks were also initially given an avian nutritional maintenance diet (Emeraid II, Lafeber Company, Cornell, IL, USA) by gastric tube to reduce weight loss in captivity due to the cessation of normal feeding. This was curtailed when two ducks died from regurgitation and inhalation of the liquid food supplement. Blood samples for CBC and serum chemistries were taken from a sample of the ducks to obtain background information of each species. All ducks received an injection of fluids (Lactated Ringers Solution, Baxter Healthcare Corporation, Deerfield, IL, USA) to replace fluids lost in surgery. Most ducks were radiographed to determine the position of the transmitter. It was learned while examining the radiographs that 45% of the ducks were carrying embedded shot from previous exposure to hunting.
Ducks were held post-surgery for periods of 1-9 days, banded, and then released at the site of capture. This study determined that one of the critical factors for survival of instrumented scoters is to assure that feathers are properly preened and dry before release to the wild. This preening process was delayed with some scoters because of the use of a pain reducing narcotic that appeared to make the ducks lethargic. We recommend only using essential medication and minimal handling with a return to the wild as soon as possible.
The current techniques
used to instrument scoters have been
modified and improved during the study.
This technique has now minimized
mortality to levels similar to other
conventional implant telemetry procedures.
These procedures will greatly aid the
conservation effort for seaducks presently
being conducted throughout the world.
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