PNW 98 Session - Full Abstracts
Full Abstract
1) Contact Author: Kathleen A. Sale
2) Institution:Oregon Istitute of Technology
3) Mailing Address: 3201 Campus Drive,Klamath Falls,OR 97601
4) Phone #:(541)885-1642
5) Email: salek@oit.edu
6) Presenter: Kathleen A. Sale
7) Paper or Poster: poster
8) Equipment needs other than standard slide and overhead projector: None
9) Contributed session 1st choice:Wildlife
10) Contributed session 2nd choice:Monitoring
11) Do you want your oral or poster presentation judged for a student award (yes or no)?: Yes
12) Would you like to be a judge for Student Awards (yes or no)?:No
13) Keywords:watershed, geese, mortality
14) Authors:
15) Affiliation/institution:
(1)Oregon Institute of Technology, Klamath Falls, OR
(2)U.S. Fish and Wildlife Service, Tulelake, CA
16) Abstract Title:
The effects of varying lake levels on Canada Goose nest mortality on the
Upper Klamath National Wildlife Refuge
17) Abstract Text:
Upper Klamath Lake, along with the connecting Agency Lake, is the second
largest lake in Oregon, with a mean depth of eight feet in proportion to
its 140 square miles of surface area. In recent years, water demands on
the lake have been increasing as a result of the need for adequate water
for: endangered sucker fish, waterfowl in the Klamath Basin Refuges,
downstream water flow for salmon, and local irrigation. These issues have
resulted in the Bureau of Reclamation increasing minimum lake elevations
from 4139.5 to 4140.3 feet with a maximum of 4143.3 feet. Rising lake
levels in the spring may impact the marsh on the north end of Klamath Lake
which encompasses the Upper Klamath Wildlife Refuge where many waterfowl
nest in the spring. The study was undertaken to ascertain the effects of
rising lake levels on Canada Goose nest mortality. Fifty nests were
selected at random. The number of eggs was recorded for each nest as was
incubation status as determined by the floatation method. The nests were
checked weekly until they were terminated by destruction, predation, or
hatching. Nest success was determined by both the Apparent and the
Mayfield Exposure Method. The Mayfield Exposure Method takes into
consideration that most nests are not found on the day they were initiated
and so may represent an already increased survival rate as other nests
initiated at the same time may have been destroyed before the nest search
took place. The Apparent method does not take this into consideration.
In the study: 22% of the nests were destroyed by predation; 16% were
destroyed by flooding; 8% were abandoned; and 54% were successfully
hatched. There did not appear to be a direct correlation between the
the rising water levels and the number of nests destroyed by flooding.
However, the proportion of nests lost to flooding may be biased downward
as the nests may have been lost to flooding and then destroyed by
predation. The rapid rise to maximum pool in Upper Klamath lake early in
the spring appears to cause significant nest mortality to Canada Geese.
However this paractice lessens impacts to other water birds nesting later
in the season, i.e. rails, diving ducks, and puddle ducks. Raising the
lake level prior to Canada Goose nesting is probably not possible in most
years because the snow melt has not occured. Also, to raise the lake
levels too early eliminates flood storage capacity of the lake. This
report is to provide information for lake level management to
minimize the impact to waterfowl that utilize the lake for nesting in
the spring.
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18) Comments/Requests:
Will easles and boards be provided for the poster presentation, or will
the entrants need to provide these?