Annual survival rates of neck-banded adult geese averaged ((x) over bar +/- SE) 0.707 +/- 0.019 during 1984-86, 0.651 +/- 0.022 during 1987-89 when harvest seasons were restricted, and 0.595 +/- 0.028 during 1990-93 when harvest seasons were liberalized. Annual survival rates for neck-banded adults were lower versus leg-banded adults during 1987-89 and 1990-93 (P less than or equal to 0.05). Mean survival of neck-banded adults during the harvest seasons in 1987-89 was lower than the mean rate in the harvest seasons of 1984-86, primarily due to a low Survival estimate in 1989. Survival averaged 0.918 +/- 0.0129 during the 1987 and 1988 harvest seasons but declined to 0.665 +/- 0.051 during 1989. Restrictions in harvest correlated with a decrease in direct recovery rates and an increase in survival rates of neck-banded adults during the 1987 and 1988 harvest seasons, but not in 1989. Higher recovery rates in 1989-92 suggested that increased harvest mortality contributed to lower survival of adult geese. However, mortality rates during the 1989-92 harvest seasons increased at a greater proportion than increases in direct recovery rates, suggesting that factors other than harvest could have significantly impacted fall mortality rates of adult geese.Estimated within-year Probabilities of movement, along with Population size estimates, suggested there was a northern shift in fall distributions of EPP Canada geese and delayed migrations during the late 1980s. Probabilities of southward movement for geese in the northern regions of the Flyway declined significantly during October and November when season lengths and quotas were reduced during 1987-89. While restrictions in harvest in 1987-89 corresponded with delays in fall movements, subsequent increases in harvest pressure in 1990-92 did not promote southward movement of geese in early fall. Geese that survived the harvest season in 1990-92 had lower rates of movement during October and early November than did geese that survived the harvest seasons in 1985-86. The gradual shift in the estimated timing of north-south movement, for birds known to have survived the harvest season, suggests mortality rates were higher for geese that moved south early in the fall in 1990-92. However, the lack of information on reporting rates and crippling loss for Canada geese prevented direct estimation of the proportion of fall mortality attributable to harvest.Our study demonstrated that a variety of factors can interact to affect the distribution of Canada geese and complicate approaches to population management. Information from marked geese is a critical tool for monitoring changes in survival and harvest rates of Canada goose populations, especially in light of recent changes in winter distributions and resultant mixing of populations. Data for EPP Canada geese indicated that neck-banded geese had lower survival and higher recovery rates than did leg-banded geese. If harvest was the major source of mortality for EPP geese, our results suggested that actual reporting rates for Canada geese were lower than rates estimated for mallards (Anas platyrhynchos). In contrast, if harvest was not the major Source of mortality for geese, then managers need to consider northarvest mortality rates when determining optimal harvest rates for sustainable populations of Canada geese. In light of recent changes in band inscriptions designed to increase reporting Fates, we recommend that managers limit the use of neck bands and that monitoring programs for Canada geese be designed to minimize potential biases due to colored auxiliary markers and differential reporting rates. We also recommend that band reporting rates be evaluated for goose populations across North America. Information on temporal and spatial differences in reporting rates would improve management efforts for EPP Canada geese by allowing a better understanding of the relative impacts of harvest and nonharvest mortality rates.

Subspecific classification of Canada geese (Branta canadensis) based on morphological measurements serves many management and research functions, such as determining harvest pressure on subspecies or estimating the population composition of wintering flocks. Despite this widespread use, the magnitude of error involved in such measurements. the effect of observer experience on measurement error, and the effect of measurement error on classification are not known. To investigate these issues, we carried out a study on Canada geese harvested in Wisconsin involving replicated measurements by observers of different experience levels. Measurement error for experienced observers was half as large as that for inexperienced observers (6-10% vs. 13-21% of all variability for all structures except the tarsus). Experienced observers measured the skull and culmen most precisely, the tarsus, least precisely. Consistent differences among observers (observer bias) that could bias classification were smaller for experienced observers. We used reference data and distributional assumptions to estimate that without observer bias or other forms of measurement error. 8-9% of geese measured would be misclassified because of actual size overlap between subspecies. Without observer bias, remaining measurement error among experienced and inexperienced observers increased misclassification by 1% and 2%, respectively. Observer bias can increase misclassification substantially beyond these levels, depending on the magnitude and direction of observer bias and the prevalence of the subspecies. Misclassification of geese resulted in overestimating the prevalence of the less common subspecies in mixed populations. which may be important in developing management strategies. We recommend training observers and standardizing measurement procedures primarily to reduce observer bias that leads to biased classification of geese, and secondarily to reduce other components of measurement error.

We undertook migration monitoring surveys and analysis of long-term banding data to determine if there was a significant premolt movement of Canada geese (Branta canadensis) from restored and reintro duced populations in southern Canada and midcontinent United States into northern Ontario and western James Bay. We examined migration chronology, origins, and demographic characteristics of molt migration of Canada geese in northern Ontario and on Akimiski Island, Northwest Territories. From 1985 to 1989, a conspicuous northward migration of large Canada geese was documented throughout northern Ontario from midMay to the end of June, well after the April migration of the subarctic nesting subspecies of Canada geese (B. c. interior); most nesting interior Canada geese in the Hudson Bay and James Bay lowlands were incubating eggs at this time. Summer-banded Canada geese originating from populations in 26 states and 6 Canadian provinces were captured in coastal areas of James Bay and Hudson Bay between the borders of Quebec and Manitoba. Morphometric discrimination indicated the presence of molting giant Canada geese (B. c. maxima) Most foreign, summer-banded birds were yearlings (53%) and 2-year-olds (17%), but birds up to 15 years old were captured. Approximately 58% of 2-15-year-old females had brood patches, which indicated a nesting attempt in the year of recapture. We suggest that increasing populations of giant Canada geese and declining habitat availability on northern brood-rearing areas will result in increasing levels of competition between populations of Canada geese. Presence of molt migrants on northern breeding areas will also complicate management of some Arctic and subaretic nesting populations of Canada geese.

Canada Geese (Branta canadensis interior) breeding on Akimiski Island, Northwest Territories. and those breeding on the Ontario mainland south west of James Bay, share a common wintering range and are considered to be part of the same population, but differ significantly in size (e.g. skull length of mainland birds averages ca. 8% greater than that of Akimiski birds). We collected eggs in each area and raised the goslings in a common environment to determine environmental effects on differences in body-size traits observed in wild birds. We found no differences in asymptotic size or growth periods for skull, culmen, and tarsus length among birds from different origins (P > 0.05) but significant differences between sexes (P < 0.05). Estimated asymptotes for skull length of captives were intermediate to those of wild insular and mainland adults but closer to those of the larger mainland birds. Captive goslings from Akimiski Island had structural measurements that averaged 8 to 17% larger than those of wild goslings of the same age on the island. These results suggest a significant environmental effect on observed differences in body size between insular and mainland populations in southern James Bay. We suggest that lower per capita food availability explains the smaller size of Canada Geese on Akimiski Island.

The apparent high visibility of goose nests in arctic habitats often has led researchers to assume that single ground counts approach complete inventories of the nesting geese in a given area. No studies to date have attempted to measure the visibility bias in these counts. Annual nest counts of Eastern Prairie Population (EPP) Canada geese (Branta canadensis interior) were conducted from 1976 to 1994 near Cape Churchill in northern Manitoba. Portions of the study area were searched by 2 independent crews in 1993-94, and a modification of the Petersen estimator was used, to estimate both visibility bias and the unbiased nest density. Individual crews located 77% (+/- 2.9%) of active and 39% (+/- 5.3%) of destroyed nests, or only 72% (+/- 2.4%) of all nests present. Single counts seem to be reliable indicators of trends in breeding parameters in our study but we recommend visibility bias be estimated where accurate nest density estimates are required.

Floating bird eggs has become a common means of determining the incubation stage of eggs in the field. However, relatively little attention has been paid to potential sources of error in this technique, and few researchers have validated the flotation method for their study species. We compared the actual ages of eggs from 351 Canada goose (Branta canadensis interior) nests with the ages predicted by flotation. Mean observed and predicted ages were not different, and 82.3% of predicted hatch dates were +/-4 days of those observed. The accuracy of estimates varied with the age of eggs floated; flotation tended to overestimate nest age early, and underestimate it later, during incubation. This flotation method was sufficient for our purposes, but we suggest the method be modified if accuracy >+/-4 days is desired. Researchers should consider all inherent sources of error and validate flotation when reporting results using this method.

We evaluated morphometric discrimination models designed to use skull length to differentiate between giant Canada geese (Branta canadensis maxima) and interior Canada geese (B. c. interior). We found significant differences in mean skull lengths of interior Canada geese from 3 areas in James Bay (Duncan's multiple range test, P < 0.05). Geese decreased in size with increasing latitude, but those from Akimiski Island did not fit this pattern, and were smaller than those from the adjacent mainland. Morphometric discrimination techniques appeared to work adequately in northwest James Bay and on Akimiski Island, but were less reliable in southern James Bay, where the largest interior Canada geese were found. Molt migrant giant Canada geese were apparent in all areas, but most were distinguishable by morphometric methods from interiors at all sites except southern James Bay. Detailed knowledge of geographic variation in body size will improve the usefulness of morphometric discrimination techniques for Canada goose research and management. We recommend the skull length models developed by Moser and Rolley (1990) for use in differentiating giant from interior Canada geese in much of the Mississippi Flyway, except where southern James Bay mainland geese occur. J. WILDL. MANAGE. 61(1):183-190

Food habits of Redheads (Aythya americana) investigated at the Horicon National Wildlife Refuge, Wisconsin, during 1983-1985. Prelaying females consumed plant material almost exclusively, primarily seeds of moist-soil plant species. The diet of laying and incubating females was dominated by seeds but also contained 16-17% animal matter. Consumption of animal matter during egg production was substantially lower than reported in other studies of food habits of Redheads. The diet of Juvenile Redheads changed with age. Animal foods were nearly half of the diet of ducklings <4 wk of age, whereas older ducklings consumed primarily plant material. A diversity of flooding regimes may promote plant communities that produce importance food resources for Redheads on the Horicon Marsh.

Effective management and conservation of blue-winged teal (Anas discors) require information on foods consumed in main wintering areas. We describe foods eaten by 84 blue-winged teal collected in Cienaga Grande de Santa Marta, Colombia, and Palo Verde Wildlife Refuge, Costa Rica. The volume of foods found in 12 blue-winged teal collected in Palo Verde in 1982-83 consisted of 92% plant and 8% animal material; cultivated rice predominated. In Cienaga Grande, foods found in blue-winged teal included 71% plant material during 1979-80 (n = 10) and 91% animal material (n = 62) in 1985-88 (P < 0.01). Water lily (Nymphaea spp.) seeds were the most common plant item. Snails (Pyrgophorus spp.) and Corixidae insects were the most prevalent animal items

An increased probability of death is thought to be an inherent risk of dispersal. To examine this hypothesis, we monitored 381 radiomarked Ruffed Grouse (Bonasa umbellus) over 6 yr to determine if their vulnerability to mortality increased during dispersal. Estimates of mortality were calculated for the two distinct phases of dispersal: transience, a period of extensive movement from one area to another, and colonization, the period when an animal attempts to become established in a new area. Among juveniles (nonresidents), approximately equal proportions of both sexes exhibited transience, and for similar lengths of time. The difference between juvenile male and female mortality estimates was not significant during either transience or colonization. From autumn to spring (natal dispersal), juvenile transient dispersers did not experience greater mortality than colonization dispersers. Among adults, transience was more common among females than males, yet no mortality was recorded among either sex of adult transient dispersers. Residents (adults) survived at a higher rate than juveniles in either transient or colonization dispersal. However, the cost (i.e., increased mortality) of transience was greater for juveniles than adults, suggesting comparisons between different phases of dispersal be made within similar age classes. It was concluded that Ruffed Grouse, both adults and juveniles, were not more vulnerable to mortality during transient dispersal than during colonization dispersal.

We examined the prevalence of lead exposure from ingestion of waste lead shot among age and sex cohorts of Canada geese (Branta canadensis) on the breeding, migration, and wintering grounds of the Eastern Prairie Population. Blood samples from 6963 geese were assayed for lead concentration by atomic absorption spectrophotometry. On the breeding grounds, no goslings and <1% of adults showed evidence of recent exposure to lead shot (i.e., concentrations in the blood elevated above the threshold value of 0.18 ppm lead). However, median background blood lead concentrations (i.e., blood samples with < 0.18 ppm lead) were higher in adults than goslings, indicating that exposure of adults to lead had occurred during previous seasons. Waste lead shot was available on the migration and wintering grounds, where a larger proportion of the blood samples from immatures (< 1 year old) than adults (> 1 year old) had lead concentrations ≥ 0.18 ppm. Median background lead levels remained higher in adults than in immatures throughout fall and winter. We also found that more immature males than immature females had elevated lead concentrations. Higher rates of intake of food and grit (including shot) probably partially account for the higher prevalence of elevated lead concentrations in immature Canada geese.

We monitored 381 radio-marked ruffed grouse (Bonasa umbellus) on public and private woodlands in central Wisconsin during 1982-88 to determine seasonal mortality rates due to predation and hunting. A total of 222 known mortalities were recorded: 159 from predation and 63 from hunting. Adult survival rates gradually decreased from 0.85 in summer to 0.57 in winter, then increased in spring to 0.73. juvenile survival was also highest in summer (0.61), but remained relatively low through all seasons. Hunting mortality rates on public hunting areas were significantly (P < 0.005) higher than on private lands for both adults (0.73 vs. 0.13) and juveniles (0.56 vs. 0.09). In contrast, mortality (viz., predation) was similar during the nonhunting season on public and private lands for both adults (0.44 vs. 0.44) and juveniles (0.80 vs. 0.77, respectively), suggesting that hunting mortality was at least partially, if not completely, additive to natural mortality. Immigration from private lands sustained grouse numbers on public lands because overall population densities gradually increased from 5.8 to 7.8 drumming males per 100 ha during the 6-year study. We conclude that ruffed grouse numbers will be substantially reduced in areas with high hunting mortality and reduced immigration due to fragmented habitat.

Canada geese (Branta canadensis) from northern Manitoba and northern Ontario were marked with leg bands and neck bands and observed throughout the Mississippi flyway f rom 1978 to 1989. We used observations of neck-banded geese within each state to determine the relative fall/winter distribution of the Eastern Prairie Population (EPP) and the Mississippi Valley Population (MVP). Mississippi Valley geese were affiliated with states east of the Mississippi River; EPP geese were affiliated with states west of the Mississippi River. However, we found geographic differences in population distribution within several states. Significant annual changes in distribution also occurred in most states. Management of Mississippi flyway geese should consider the differences in both population dynamics and spatial and temporal distributions of MVP and EPP geese in determining state and flyway harvest objectives.

Biologists who study neck-banded Canada Geese (Branta canadensis) have used capture and resighting histories to estimate annual resighting rates, survival rates and the number of marked birds in the population. Resighting errors were associated with 9.4% (n = 155) of the birds from a sample of Canada Geese neckbanded in the Mississippi flyway, 1974-1987, and constituted 3.0% (n = 208) of the resightings. Resighting errors significantly reduced estimated resighting rates and significantly increased estimated numbers of marked geese in the sample. Estimates of survival rates were not significantly affected by resighting errors. Recommendations are offered for using neck-band characters that may reduce resighting errors.

Lead poisoning in waterfowl has a long, welldocumented history as a wildlife management problem (Sanderson and Bellrose 1986). Since 1976, nontoxic shot zones have been implemented across the United States in an effort to reduce availability of lead pellets, and nationwide mandatory use of nontoxic shot for hunting waterfowl is scheduled to begin with the 1991-1992 waterfowl hunting season (U.S. Fish and Wildl. Serv. 1988). Although compliance with nontoxic shot regulations is high in some areas (Simpson 1989), controversy persists because some hunters and hunting organizations are not convinced that lead poisoning is a problem or that steel shot is the solution (Smith and Townsend 1981, Sanderson and Bellrose 1986). Furthermore, lead shot is still used in Canada (Schwab and Daury 1989). Because dwindling habitat has concentrated waterfowl and hunters onto smaller areas, decades of hunting have built up high densities of lead shot on some areas (Sanderson and Bellrose 1986, U.S. Fish and Wildl. Serv. 1988). Eliminating or reducing the lead shot available to birds is still an important aspect of waterfowl management. We studied lead exposure in the Eastern Prairie Population of Canada geese (Branta canadensis interior), a population of 170,000230,000 individuals (DeStefano 1989),

Nest initiation and hatch dates of Snow Geese (Chen caerulescens) and two races of Canada Geese (Branta canadensis) nesting in Hudson Bay became progressively earlier in the period 1951-1986. Snow Geese might have been adjusting to the milder climate of recently-colonized breeding areas in southern and western parts of the bay, but because other species showed the same trend of nesting dates, we suggest instead that the cause was climatic amelioration.

We used capture, harvest, and observation histories of Canada geese (Branta canadensis) banded in the Mississippi flyway, 1974-88, to examine the problem of neck-band retention. Methods for the analysis of survival data were used to estimate rates of neck-band retention and to evaluate factors associated with neck-band loss. Sex, age of bird at banding, rivet use, and neck-band type significantly influenced neck-band retention. For most of the resulting cohorts (e.g., sex, age, rivet, and neck-band type categories), neck-band retention rates decreased through time. We caution against using small samples or data collected during short-term studies to determine retention waves. We suggest that observation data be used in neck-band retention studies to increase the efficiency of estimating retention time