Download or read book Sources of Variation in Waterfowl Nest Predation written by Karla L. Guyn and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nest loss is an important factor reducing the reproductive success of ground-nesting birds. However, it is unclear why certain nests hatch whereas others are destroyed by predators. Consequently, I performed experiments with conditioned taste aversion and measured characteristics of natural and simulated duck nests to evaluate clutch survival in relation to: i) avian and mammalian predation; ii) nest location (site, habitat, distance to edges); iii) time; iv) spatial dispersion of nests;and v) vegetative characteristics around nests. Previous studies have examined the efficacy of conditioned taste aversion (CTA) in reducing egg predation at site baited with eggs, but not at natural nests. Therefore, I evaluated whether CTA might be generalized, protecting eggs in natural nests of ducks in southcentral Saskatchewan. Consumption of eggs was monitored at baiting sites placed near nests of American crows and in locations likely to be frequented by mammals. During the treatment period, eg.
Download or read book Nest Site Selection Patterns of Dabbling Ducks in Response to Variation in Predation Pressure written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nesting success is an important vital rate affecting the reproductive fitness of birds, and predation typically is the single most important factor affecting nesting success. Presumably, birds should nest in locations that maximize nest survival. If specific nest characteristics increase the probability that a nest will hatch, natural (phenotypic) selection could favour use of sites with these features, producing nonrandom patterns of nest site use. Alternatively, birds that are highly selective in nest site choices might be at a disadvantage if predators learn to forage preferentially in these locations and improve their efficiency in depredating nests; in this case, random nesting patterns could be favoured. Finally, it has been hypothesized that predation pressure can influence nest site selection patterns of entire bird communities. If predators develop a search image to hunt for bird nests, then nests that are most similar to each other, irrespective of species, should sustain higher mortality. To evaluate these hypotheses, I quantified nest site selection patterns of multiple species of ground-nesting dabbling ducks in areas where predation pressure was normally high, and compared these patterns to those on areas where predation was relaxed. Predation pressure was experimentally reduced by removing common predators of duck nests and females (mainly red foxes, coyotes, skunks and raccoons) on some study areas and not on others (controls). Predator removal and natural causes produced a 10-fold difference in duck nesting across study sites, allowing for investigation of effects of predation pressure on nest site selection of ducks. Coarse scale habitat selection patterns were similar to results reported in previous studies; blue-winged teal and northern shoveler were found more often in native grassland than in other habitat types, while gadwall and mallard nests occurred more frequently in shrub patches when compared with other habitat patches. A difference in n.
Download or read book Nest Site Selection Patterns of Dabbling Ducks in Response to Variation in Predation Pressure written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nesting success is an important vital rate affecting the reproductive fitness of birds, and predation typically is the single most important factor affecting nesting success. Presumably, birds should nest in locations that maximize nest survival. If specific nest characteristics increase the probability that a nest will hatch, natural (phenotypic) selection could favour use of sites with these features, producing nonrandom patterns of nest site use. Alternatively, birds that are highly selective in nest site choices might be at a disadvantage if predators learn to forage preferentially in these locations and improve their efficiency in depredating nests; in this case, random nesting patterns could be favoured. Finally, it has been hypothesized that predation pressure can influence nest site selection patterns of entire bird communities. If predators develop a search image to hunt for bird nests, then nests that are most similar to each other, irrespective of species, should sustain higher mortality. To evaluate these hypotheses, I quantified nest site selection patterns of multiple species of ground-nesting dabbling ducks in areas where predation pressure was normally high, and compared these patterns to those on areas where predation was relaxed. Predation pressure was experimentally reduced by removing common predators of duck nests and females (mainly red foxes, coyotes, skunks and raccoons) on some study areas and not on others (controls). Predator removal and natural causes produced a 10-fold difference in duck nesting across study sites, allowing for investigation of effects of predation pressure on nest site selection of ducks. Coarse scale habitat selection patterns were similar to results reported in previous studies; blue-winged teal and northern shoveler were found more often in native grassland than in other habitat types, while gadwall and mallard nests occurred more frequently in shrub patches when compared with other habitat patches. A difference in n.
Download or read book From Individuals to Populations written by Joshua Timothy Ackerman and published by . This book was released on 2002 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Ecology and Management of Breeding Waterfowl written by and published by U of Minnesota Press. This book was released on 1992 with total page 812 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nest Success and Female Survival of Wood Ducks in Nevada written by Steven Michael Olson and published by . This book was released on 2011 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: Overexploitation and depleted nesting habitat led to the near extinction of the Wood Duck 100 years ago. Since then restrictive harvest and nest box programs have led to a population rebound. Wood ducks are now among the top five duck species shot annually in the United States. This thesis focuses on two aspects of their population growth: nest success and female survival. The first chapter addresses sources of variation in nest success of a Wood Duck population in Nevada from 2003-2010. Among ducks, females tend to experience lower annual survival than males. Increased risk of predation while on the nest and the physiological cost of breeding, thermoregulation, and daily activity have been hypothesized to explain the differences between male and female survival. The second chapter assesses hypotheses about the effects of reproductive investment by female Wood Ducks. Specifically, assessments were conducted on sources of variation in survival related to time of year, female quality, and parasitism.
Download or read book Alternate Prey and Habitat Characteristics Affecting Waterfowl Nest Predation written by Robert L. Crabtree and published by . This book was released on 1984 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Analysis of Nesting Mortality in Birds written by Robert E. Ricklefs and published by . This book was released on 1969 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Testing Competing Hypotheses for the Seasonal Variation in Nesting Success of a Late nesting Waterfowl written by Kalen John Pokley and published by . This book was released on 2014 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Populations of lesser scaup and greater scaup have been below the North American Waterfowl Management Plan goal of 6.3 million since 1984. As of 2013, scaup populations are down 12% from their long term average (1955-2013) of 4.7 million birds (Walker 2005). Nesting success has shown to be an important factor in determining population growth. If the mechanisms of nesting success can be identified wildlife managers can make the necessary changes to increase scaup nesting success and thus increase the population. Nests were located during nest searches conducted from May through July and monitored until fate was determined. Nest age, nest location, vegetation height, distance to water and depth of water were recorded at each nest. Program MARK was used to determine known fate models. The model that incorporated both nest age and the effect of nest date showed the greatest support. I found a greater influence of date on nesting daily survival rate than age during this study, although both positively influenced scaup nest daily survival rate. The positive relationship between scaup nest daily survival rate and date, provided support for the nest concealment hypothesis. This posits that increasing vegetation height and density throughout the nesting season decreases predation. Sugden and Beyersbergen (1987) found similar results that artificial nests in tall, dense nesting cover escaped predation from crows for longer than those in sparse cover. The positive effect of nest age on nest survival supports the nest heterogeneity hypothesis, i.e., that low quality nests are depredated at a higher rate than nests of higher quality. Although these results have been supported by others (Klett and Johnson 1982) it has not received unanimous support. It is possible that these results might be influenced by the lack of heterogeneity in vegetation and differences in predator community at Red Rock Lakes National Wildlife Refuge compared to other sites.
Download or read book Effectiveness of Lithium Chloride in Reducing Waterfowl Nest Predation written by Susan E. Scheaffer and published by . This book was released on 1982 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predator Prey Dynamics written by Michael R. Conover and published by CRC Press. This book was released on 2007-03-30 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Humans, being visually oriented, are well versed in camouflage and how animals hide from predators that use vision to locate prey. However, many predators do not hunt by sight; they hunt by scent. This raises the question: do survival mechanisms and behaviors exist which allow animals to hide from these olfactory predators? If so, what are they, a
Download or read book Ecology and Conservation of North American Sea Ducks written by Jean-Pierre L. Savard and published by CRC Press. This book was released on 2015-04-13 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past decade has seen a huge increase in the interest and attention directed toward sea ducks, the Mergini tribe. This has been inspired, in large part, by the conservation concerns associated with numerical declines in several sea duck species and populations, as well as a growing appreciation for their interesting ecological attributes. Reflec
Download or read book Our Living Resources written by and published by . This book was released on 1995 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: Report provides information on distribution, abundance, and health of birds, mammals, reptiles and amphibians, fishes, invertebrates, plants, terrestrial ecosystems, aquatic ecosystems, coastal and marine ecosystems, riparian ecosystems, the Great Plains, Interior West, Alaska, and Hawaii. It also discusses special issues: global climate change, human influences, non-native species, and habitat assessments.
Download or read book Video Surveillance of Nesting Birds written by Christine Ann Ribic and published by Univ of California Press. This book was released on 2012-06-12 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: Declining bird populations, especially those that breed in North American grasslands, have stimulated extensive research on factors that affect nest failure and reduced reproductive success. Until now, this research has been hampered by the difficulties inherent in observing nest activities. Video Surveillance of Nesting Birds highlights the use of miniature video cameras and recording equipment yielding new important and some unanticipated insights into breeding bird biology, including previously undocumented observations of hatching, incubation, fledging, diurnal and nocturnal activity patterns, predator identification, predator-prey interactions, and cause-specific rates of nest loss. This seminal contribution to bird reproductive biology uses tools capable of generating astonishing results with the potential for fresh insights into bird conservation, management, and theory.
Download or read book Canadian Journal of Zoology written by and published by . This book was released on 2008-05 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Video Surveillance of Nesting Birds written by Christine Ann Ribic and published by Univ of California Press. This book was released on 2012-05-13 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: “Until recently, inferring identities of predators and monitoring cryptic behaviors at the nest was time-consuming, often with anecdotal results. No more. Video nest surveillance, so aptly revealed in this volume, has ushered in a new era of data collection that allows field workers to link environmental factors with such aspects as the temporal dynamics of predator communities in relation to what the birds are doing at their nests, thus removing much of the guesswork of earlier studies.”--Spencer G. Sealy, University of Manitoba "Video Surveillance of Nesting Birds shatters earlier beliefs about how birds interact with nest predators. Much of what we thought we knew about nesting and its hazards was flat-out wrong, as authors in this book discovered by using modern technology in the field. As simple as we would like our models of animal behavior to be, this book shows that reality is far more complex and nuanced."--Douglas H. Johnson, University of Minnesota
Download or read book Effects of Olfactory and Visual Predators on Nest Success and Nest site Selection of Waterfowl in North Dakota written by Jennifer Suzanne Borgo and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Selecting a nest site is an important decision for waterfowl. Because most nest failure is due to depredation, the primary selective pressure in choosing a nest site should be to reduce depredation risk. This task is difficult because predators use differing tactics to locate nests, such as olfactory or visual cues. I investigated several components of waterfowl nest-site selection and success on sites with shelterbelts (planted tree-rows) in North Dakota, during the 2006 and 2007 nesting seasons. I found that meteorological conditions impacted nest depredation; artificial nests were more likely to be depredated when either temperature or dew point was high. These meteorological conditions should improve foraging efficiency for olfactory predators by increasing odor concentration. Waterfowl selected nesting sites with greater visual concealment than random locations (lateral concealment). However, the only difference found between successful and depredated nests was lateral dispersion, an olfactory concealment characteristic. Nest density was higher in areas without shelterbelts than in areas near shelterbelts. Nest success for waterfowl decreased as shelterbelt height increased. Other shelterbelt characteristics, like porosity and orientation, did not affect nest success or nest density. Given that nest predators differ in foraging habitat, temporal patterns of activity, and searching modalities, nest site characteristics that conceal the nest from 1 predator species may increase its vulnerability to another predator. For instance, risk due to olfactory predators should be reduced near shelterbelts because locating nests would be more difficult as turbulence is generated by the shelterbelts. Concomitantly, shelterbelts could also increase the presence of visual predators, by providing nesting sites and vantage points. In my study, any benefits shelterbelts provide in reducing nest depredation by olfactory predators may have been offset by increasing nest depredation from visual predators. Hence nesting near shelterbelts was neither a liability nor a benefit to ducks.
