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
Conservation Assessment for the Dusky Canada Goose (Branta canadensis occidentalis Baird)
Bromley, Robert G.; Rothe, Thomas C. 2003. Conservation assessment for the dusky Canada goose (Branta canadensis occidentalis Baird). Gen. Tech. Rep. PNW-GTR-591. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 79 p. Dusky Canada geese compose one of the smallest populations of geese in North America and have exhibited a marked decline in the past 30 years. A comprehensive synthesis of past and current biological information on the subspecies has been compiled to provide insights into the ecology and demography of the population, as well as explore management efforts to promote long-term conservation. Duskys occupy a discrete range, which has allowed the development of focused, long-standing management programs. The 1964 Alaska earthquake set in motion significant ecological changes in wetlands, plant communities, and the suite of predators on the dusky goose breeding grounds. A subsequent decline in goose productivity has become the primary challenge to this population. Concurrently, habitats on the western Washington and Oregon wintering grounds became more favorable for geese, but over 250,000 Canada geese of five other subspecies now occupy the region where formerly duskys were the majority. In the 1960s, the harvest of dusky geese was recognized as a primary management concern and regulation was effectively implemented. At present, protection of diminished duskys amid 10 times as many other Canada geese has created great complications for both management of hunting and attention to increasing complaints of crop depredation by wintering flocks. Important information needs are suggested to improve population monitoring, evaluate specific causes of lost productivity, and assess the direction and effects of succession of breeding ground habitats and conversion of winter habitats.
Indian Fig Cactus (Opuntia Ficus-Indica (L.) Miller) in the Americas: an Uncertain History
Abstract: 
 Opuntia ficus-indica (L.) Miller is a globally important cactus species with a long history of human use. In addition to the importance of O. ficus-indica as a food for humans and livestock, it also has long served a role in the production of cochineal, a once important textile dye. This cactus also is intimately interwoven into the story of Cactoblastis cactorum (Berg) (South American cactus moth), one of the best-known examples of biological weed control. In this regard, O. ficus-indica has been a target weed as well as an unintended host in C. cactorum invasion. Although the distribution and human-assisted movement of this cactus throughout much of the world is well documented, surprisingly little has been written about its history and movement within the Americas. Literature associated with Opuntia and their phytophagous pests in North and South America was examined in an attempt to determine the history of O. ficus-indica in the Americas. Available information suggests with some certainty that O. ficus-indica originated in present-day Mexico, but the timing of its introduction to South America is much less clear. Taxonomic difficulties associated with distinguishing among Opuntia species and the long pre-Columbian history of exchange between South American and Mesoamerican cultures are two primary complicating factors associated with dating the dispersal of this species to South America. Additionally, previous evidence in support of a pre-Columbian introduction to South America relied on questionable identification of insect-based textile dyes. These uncertainties are significant because clearer knowledge of the history of O. ficus-indica introduction to South America could provide a more complete biological and ecological context to efforts at managing this species in its native and introduced ranges, particularly with respect to the threat posed by C. cactorum in North American and Argentinean plantations.