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Canada Goose Nesting

1950 - ongoing,   Brett Tiller

Population studies of the western Canada goose (Branta canadensis moffitti Aldrich) nesting on islands in the Hanford Reach of the Columbia River have been conducted since 1950. The initial purpose of the studies were to document the reproductive performance of the goose population to determine whether nesting performance would demonstrate a delayed response due to nuclear reactor operations. Continuous documentation of nesting performance also provides a way to evaluate the effect of industrial uses of Columbia River water and changes introduced by hydroelectric dams and turbine additions upstream, and increased recreational use of this region.

Twenty islands provide almost all of the goose nesting habitats along the Hanford Reach. This area is 88-km in length. The report by Hanson and Eberhardt details the vegetation for each island in 1970. (Hanson, W.C. and L.L. Eberhardt, 1971. A Columbia River Goose Population 1950-1970. Wildlife Monographs, No 28, December 1971)

Sampling methods (Hanson and Eberhardt) entailed surveying the nests beginning the first week in April, unless mild temperatures and early geese pairing was noted. The islands were systematically searched by 2 people who walked the island in the same manner each time. Careful counts of paired geese were made during the first 2 or 3 surveys prior to hatching. As each nest was found, a numbered 6-ft marker was placed near the nest and the status of the nest recorded. Incubated nests were characterized by the presence of the female, warm eggs with glossy appearance, and substantial amounts of down. Deserted nests often had a smaller number of eggs, lack of down, and showed definite impressions of cold eggs. Nests classed as destroyed were those with missing or broken eggs and scattered down. Successful nests contained the shells and membranes of hatched eggs, filoplumes from natal down, "pipped" eggs or goslings. All eggs remaining in successful nests after departure of brood were broken to determine their status. Those eggs with yolk wholly or partially suspended in the albumen were classified as infertile, whereas fertile eggs contained embryos that died in various stages of development. Dead or abandoned goslings, generally the result of weakness, crowding or lateness in hatching, were also recorded.

Weekly checks of nests were made until incubation terminated (about mid-May), unless remoteness of a few nests widely scattered over the 88-km study area made it infeasible to continue.

For the period 1971-1981 (Fitzner, R.E. and W.H. Rickard, 1983. Canada Goose Nesting Performance along the Hanford Reach of the Columbia River, 1971-1981. Northwest Science 57:267-272), nesting surveys were conducted biweekly and usually began the first week of April. Fitzner and Rickard note that parameters such as nesting phenology, nesting success and fate of eggs are sensitive to frequency of observation periods, so there may be difference between the pre-1970 data.

Codes for data collected up 1992 are as follows: islands are numbered 1 to 20 with 1 being the northern most and 20 the southern most (map), BL is for bluffs; nests are numbered for identification; vegetation type is recorded; date is entered as month and day; and status is I for incubating, P for pipped, N for not-incubating, and H for hatched.

For 1993 Canada goose nesting survey, codes used were L= laying (not used before), I= incubating, P= predated (same as destroyed, which is used also), D= deserted, H= hatched, Infert= infertile, Unknown = unable to relocated nest during subsequent visits and/or fate of nest or eggs unknown.

For 1994 and 1995 the following codes were used: I= incubating, H= hatching, U= unknown, D= destroyed (predated), A= deserted (abandoned), L= laying, F= flooded. Due to budget restraints future goose nesting surveys will be conducted biannually.

For more information on this study and others, please go to the Ecological Monitoring and Compliance Project website.