NECK COLLAR RETENTION IN DUSKY CANADA GEESE
--A total of 4965 Dusky Canada Geese (Branta canadensis occidentalis) were neckcollared on the Copper River Delta, Alaska, in 1984-1990. Collar retention rates for adult geese were obtained from examination of 910 recaptures. The effects of sex, collar age and collaring year on retention rates were determined using logit models. As there was a significant interaction between the effects of sex and collar age on retention rates, the sexes were modeled separately. The average annual retention rate for female geese (0.875 ___ 0.163 SE) was independent of all effects considered. Retention rates for males was influenced by collar age and the year collared. It is concluded that collar losses were substantial and that losses pecific to the years modeled should be considered in any population model. RETENCI•N DE ANILLOS EN EL PESCUEZO POR PARTE DE INDIVIDUOS DE BRANTA 1⁄2ANADENSIS OCCIDENTALIS Sinopsis.--Entre el 1984-1990 un total de 4965 individuos de gansos del Canada (Branta canadensis occidentalis) fucron anillados cn la pescuezo en el delta del Rio Copper, Alaska. La retenci6n de las anillas, pot parte dc adultos, fue obtenida del estudio de 910 individuos rccapturados. E1 efecto dcl sexo, edad dc la anilla y afio de la anillada, en la tasa de retcnci6n de anillas, fuc determinada utilizando modelos dc "logit." Como hubo una interaccion significativa entre el efecto del sexo y edad de la anilla, en la tasa de retenci6n, se hicieron modelos separados para ambos sexos. La retenci6n promcdio anual para hembras (0.875 + 0.163 EE) result6 set indepcndiente dc todos los otros efectos considerados. La tasa dc rctcnci6n cn los machos fue influcnciada pot la cdad de la anilla y el afio dc anillamiento. Sc concluye quc las p6rdidas de las anillas fue sustancial, y quc los extravlos en aftos particulates deben set consideradas en cualquier modelo poblacional. Neck collars have been used to mark geese for several decades (Marion and Shamis 1977). Observations of these birds have provided much valuable information about population dynamics (Hestbeck and Malecki 1989, Rusch et al. 1985), migration (Craven and Rusch 1983, Koerner et al. 1974, Raveling 1978, Trost et al. 1980), and behavior (Macinnes and Lieff 1968). Recently, observations of marked geese have been applied in methods used to estimate survival probabilities (Ebbinge and van Biezen 1987, Hestbeck and Malecki 1989, Raveling and Zezulak 1988, Rusch et al. 1985, Yparraguirre 1982), statistics that have traditionally been calculated from models utilizing band recovery data (Brownie et al. 1985). These models generally do not account for marker loss (Brownie et al. 1985, Pollock and Raveling 1982), which is probably of little consequence for-short lived species. In the case of potentially long-lived animals such as geese, however, marker loss may severely affect survival estimates (Nelson et al. 1980). The Dusky Canada Goose (Branta canadensis occidentalis), which nests primarily on the Copper River Delta, Alaska, and winters in the Willamitte Valley in Oregon and southwestern Washington, has steadily declined in number since 1979. Harvest was restricted in 1984 and is
Effects of plastic neck collars on the behaviour and breeding performance of geese and their value for distant recognition of individuals
Johnson, I. P. & Sibly, R. M. 1989. Effects of plastic neck collars on the behaviour and breeding performance of geese and their value for distant recognition of individuals. Ring. & Migr. 10: 58–62. Neck collars made from ‘Vynalast’, a thermoplastic engraving laminate, were fitted to 165 Canada Geese in southern England during 1982–1984. The collars, each engraved with a unique two-letter code, could be used to identify individuals at distances of up to 500 m. The behaviour of the geese was not adversely affected by the collars, with collared and uncollared birds having very similar time budgets. Breeding success tended to be higher in collared than in uncollared birds, but this can be attributed to the greater age and experience of collared individuals. The retention rate was 76.3% for the first year, with 55.5% of collars being retained for two years. It is concluded that such collars are ideal for intensive short-term studies of large waterfowl (swans and geese), where it is necessary to identify larg...
A continental study of Whistling Swans using neck collars
Using coded colour neck collars increased the resighting rate of Whistling Swans Cygnus c. columbianus as individuals to as much as 90%, compared with less than 5% by conventional band methods, even after a migration across N. America. Details of the continental marking protocol for four swan species are given. Much public interest and co-operation has resulted from the use of collars.