22 March 2001
ANCHORAGE
GOOSE STUDY UNDERWAY Biologists
with the U.S. Geological Survey’s, Alaska Science Center - Biological
Science Office surgically implanted radio transmitters in 100 Anchorage Canada geese
during the summer of 2000 and plan to do the same this summer.
The study was designed to measure the effects of
surgically-implanted radios on geese.
Biologists are also gathering data on movements of geese within
the Anchorage Bowl. That
information may help local wildlife managers assess how often birds move
into areas where they are in conflict with humans. Surgically
implanted radio transmitters have been used in Alaskan waterfowl over
the past seven years to study migration and determine locations of
wintering areas. The
technique was developed because some birds do not tolerate radio
transmitters that are attached to the outside of the body.
Discoveries resulting from surgically implanted radios have
contributed to efforts to conserve wild populations.
Biologists used surgically-implanted transmitters to locate the
Bering Sea wintering area of spectacled eiders, a threatened species
that nests in western and northern Alaska.
Surgically implanted radios transmitters have also been used by
USGS to study the lingering effects of the Exxon Valdez oil spill
on harlequin ducks in Prince William Sound, response of white-fronted
geese to aircraft disturbance, and migration of emperor geese from the
Yukon Delta to their wintering areas on the Alaska Peninsula and
Aleutian Islands. USGS
plans to use surgically implanted radios to study the spring migration
of geese and their nesting efforts on breeding grounds.
However, before doing so biologists need to verify that the
radios do not influence behavior and nesting by geese.
The advantage of using Anchorage geese in this study is that the
birds are more easily observed than in wild populations. The Anchorage
population of geese is also quite healthy making capture and marking of
an adequate number of birds possible. Surgeries
are conducted by a USGS veterinarian with over seven years of experience
in implantation of radio transmitters. There were no mortalities during
surgeries last year and birds recovered quickly.
Following surgery, the flexible antenna that protrudes above the
bird’s tail is the only part of the transmitter that is visible. In
addition to geese that received surgically-implanted transmitters,
biologists also put colored plastic leg bands on an additional 69 birds
that served as a control group. They then monitored behaviors of the two
groups and found that surgical implantation of radios caused no change
in the behaviors of birds. However,
long term effects on reproduction have yet to be determined.
Therefore, this spring biologists will locate nests of females to
determine whether nesting by females with radios is similar to females
without radios. Biologists will also compare survival of the two groups
over the next three years. This project is not part of ongoing efforts by state and federal agencies to reduce the population of Anchorage Canada geese. However, information collected during the study will improve understanding of the local population and may help wildlife managers reduce conflicts between geese and people.
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