The Mortality, Behavior, and Homing of Transplanted Juvenile Canada Geese

Abstract

During the summers of 1967 and 1968, 273 flightless 7-and 8-week-old Canada geese (Branta canadensis maxima) were transplanted about 100 miles from their natal lakes near Brooks, to release sites northeast of Hanna, Alberta. All transplants received leg bands and colored neck collars for field identification. A preflight mortality of 4 percent was calculated. Postflight locations, identity, and behavior of transplants were recorded. Feeding was the major daily preflight activity of transplants, and occurred most intensively at sunrise and sunset. Resident geese were dominant over transplants. Non-breeding resident geese were more tolerant of transplants than were breeding pairs. The postflight movements of transplants were localized and as a unit under the leadership of resident birds. Transplants on release sites unoccupied by resident geese dispersed from these lakes in small groups immediately after attaining flight. From 68 birds of each sex (136) transplanted in 1967, 13 homing female yearlings were recorded in the spring of 1968. In the spring of l969, 22 females and 22 males vere observed cyn the area from a potential of 64 males and 73 females transplanted the previous summer. Homing of yearling females was significantly (P < 0.05) higher than for yearling males. Eighty-five and 86 percent of the initial sightings of yearling females in 1968 and 1969 respectively, were on or within 1 mile of their release sites. In 1969, 32 percent of the initial sightings of yearling males were on or within 1 mile of their release sites. Eighty percent of the homing yearlirlg females formed pair relationships during 1968 and 196g, with 68 percent occurring on the study area. Females appeared attracted to their release sites whether they were paired or unpaired. Sixty-eight percent of the yearling males showed pairing tendencies in 1969. Twenty-seven percent of these pair associations occurred on the study area. Of the yearling males returning, only those forming pair associations remained on the study area for 30 days or longer. Apparently the males were more attracted to the females in the pair associations than to their release sites. The pair bonds of some of the yearling females appeared to become unstable just prior to the summer molt migration C'o 2-year-old males were known to home to the area. Five 2-year-old females homed to and paired on their release sites. One 2-year-old female nested and successfully raised a brood of 5 goslings. The natural dispersion of large Canada geese throughout their original breeding range, as delineated by Hanson ( 1965 ), can best be described as slow, even under optimum habitat conditions. This lack of pioneering may be due to certain physiological and behavioral characteristics. Mayr ( 1942 ) stated that strong intrafamily bonds played an important role in the subspeciation of Canada geese over areas where geographic barriers were lacking. With reference to geese in general, Johns1 A joint contribution from the Alberta Fish and Wildlife Division and the Zoology and Entomology Department, Montana State University, Bozeman. Published as Journal Series 156. Montana Agricultural Experiment Station. 2 Present Address: 411 28 Avenue, N. W., Calgary 43, Alberta, Canada. gard ( 1965 ) attributed slow increase in numbers and lack of gene mixing to delayed maturation and permanency of pair bonds respectively. Sherwood ( 1967) confirmed the formation of both pair and intrafamily bonds. He also found a lack of dispersion from the natal area, particularly by females. Because Canada geese are important for their aesthetic and sporting qualities, biologists have attempted to artificially establish lo-cal breeding populations by using captive flocks or by transporting and releasing juveniles. These attempts have produced variable results. Pirnie ( 1938 ) concluded that the restocking of Canada geese by captive flocks was successful in southern Michigan. Williams and Kalm-