Before implementing nontoxic shot requirements for hunting waterfowl and American coots Fulica americana in the United States in 1991, the U.S. Fish and Wildlife Service monitored lead poisoning in waterfowl on federal and state wildlife hunting areas during 1983-1986. Federal and state collaborators collected gizzards and livers from 9,029 hunter-killed waterfowl (10 species of dabbling ducks Anatinae, 9 diving ducks Aythyinae, 5 geese Anserinae, and tundra swans Cygnus columbianus) across the four flyways. At the U.S. Fish and Wildlife Service National Wildlife Health Center, Madison, Wisconsin, waterfowl gizzards were examined for ingested lead and nontoxic shot and livers were analyzed for lead concentrations. Diving ducks had the greatest frequency (8.7%) of one or more ingested lead shot, followed by dabbling ducks (5.5%) and geese (1.3%). No ingested shot were found in tundra swans. The frequency of elevated (≥ 2.0 mg/kg wet weight) liver lead concentrations was also greatest in diving ducks, followed by dabbling ducks and geese. Within each species group, the frequency of elevated liver lead concentrations was greater than ingested lead shot, an indication that lead shot ingestion alone underrepresents lead exposure. Thus, lead in the liver may remain elevated after the erosion and excretion of lead pellets from the gizzard. Our results provide historical baseline data and summarize a nationwide study of lead exposure, using both ingested lead shot and liver lead concentrations, in waterfowl in the United States before the implementation of nontoxic shot regulations in 1991. These data can be compared with previous studies of lead exposure in waterfowl, as well as current and future assessments to evaluate the success of nontoxic shot regulations nationwide and specifically within previously sampled waterfowl management areas.
Due to the steady decline of waterfowl hunters, several studies have investigated means to bolster the waterfowl hunter population. Documented declines in waterfowl hunter participation are particularly worrisome as funding for the conservation of North American waterfowl habitat is dependent on the annual purchase of Federal Migratory Bird Hunting Conservation Stamps by is dependent on the annual purchase of Federal Migratory Bird Hunting Conservation Stamps by migratory bird hunters. One method of recruiting new waterfowl hunters is through mentoring by existing members of the hunter population. These mentors serve an important role in the propagation of waterfowl hunting participation and the continued funding of waterfowl conservation. Given the importance of mentors to hunter participation, we sought to discover at what age hunters were most likely to mentor new individuals. Using data from a survey of Central Flyway waterfowl hunters, we found that during the time of the survey, between the ages of 20 and 50 years had a ~0.50 probability of taking someone waterfowl hunting who had never gone before. Hunters in their sixties, seventies, and eighties had a 0.20, 0.24, and 0.18, respectively, probability of mentoring a new hunter. If increasing the waterfowl hunter population remains a goal wildlife agencies, recruitment programming may wish to consider the promotion of mentoring activity by existing hunters well before the age of 60 years.
American black ducks Anas rubripes (hereafter, black ducks) are an important game species in the eastern United States (U.S.) and Canada that declined between the 1950s and 1990s, which resulted in the implementation of restrictive hunting regulations in the United States and Canada. Black duck harvest is managed by the Black Duck International Adaptive Harvest Management (BDAHM) strategy that was developed between Canada and the U.S. The strategy requires that the black duck population be maintained at a level that is commensurate with legal mandates, provides for use appropriate for the habitat carrying capacity, and managed in a manner that maintains equitable access (between Canada and the U.S.) to the black duck resource. Fulfilling these mandates requires unbiased country-specific harvest probability estimates, which in turn require estimates of band reporting probability, that is, the probability that a hunter who harvests a banded bird will report it to the North American Bird Banding Program (NABBP; i.e., either the US Bird Banding Lab (BBL) or Canadian Bird Banding Office (BBO)). We conducted a reporting probability study during the 2017-18, 2018-19, and 2019-20 hunting seasons, using reward bands to estimate continental and country-specific band reporting probabilities. The continental (pooled) band reporting probability was 0.80 (0.660–0.945, 95% confidence interval). Band reporting probability was lower in Canada 0.65 (0.487—0.821, 95% CI) than in the United States 1.00 (0.978–1.022, 95% CI), but increased in both countries since they were last estimated in the 2000s. Increased reporting probability, as well as the difference in reporting between the two countries, should be accounted for to most effectively meet the objectives of the BDAHM strategy.
Beaver Castor canadensis create ecological refugia against drought, heat stress and fire, and policies to support beaver conservation and recolonization in regions where they have been historically extirpated are increasingly common. Between prolonged periods of drought, arid regions are increasingly challenged by extreme precipitation events that promote flash floods, debris flows, and mudslides—a phenomenon known as “whiplash weather”. Understanding how beaver wetlands respond to whiplash weather will help inform the development of restoration policies targeting the species as a natural climate solution. We used remotely sensed normalized difference vegetation index data to characterize the influence of beaver complexes on riparian greenness dynamics under whiplash weather by comparing three complexes and five nearby reference areas along the Salinas River, California. Our study region is within a remanent patch of the historic range of beaver and is highly impacted by agricultural and urban uses. Despite these limitations to expansion and their low density due to historical extirpation, the Salinas River beaver complexes demonstrated greater riparian greenness resistance to drought and resilience to flood disturbance than the watershed reference areas. Thus, policies supporting beaver re-colonization—even within highly fragmented and anthropogenically impacted habitats—may confer both riparian resistance and resilience to increasingly erratic climatic conditions.
In the early 1900s, wood duck Aix sponsa populations experienced severe declines due to unregulated hunting and habitat destruction. Federal protection under the Migratory Bird Treaty Act of 1918 and the implementation of nest box programs facilitated their recovery such that sport harvest resumed in 1941. In 2008, the bag limit for wood ducks during the general duck season increased from two to three daily, a change projected to increase the harvest rates. However, estimating harvest and survival rates of adult females remains challenging due to the difficultly of capturing them during preseason banding operations. We analyzed data from 2001-2014 from box-nesting female wood ducks in Louisiana using a live-dead model to estimate survival and calculate harvest rates. Our results indicate the bag limit increase had minimal impact on the survival and harvest rates of box-nesting females. The mean annual survival rate was 68%, with no changes after the increase in bag limit in 2008. Harvest rates also remained consistent across the study period, averaging 3%. Our findings suggest the increase in bag limit has not adversely affected survival of box-nesting wood ducks in Louisiana, allowing for additional hunting opportunities without compromising conservation goals for adult female wood ducks in the state.
