Browsing by Subject "Nest Survival"

Now showing 1 - 3 of 3
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    Breeding Ecology and Conservation of Ground-Nesting Waterbirds in North America and Southeast Asia
    (2016-12) Claassen, Andrea
    Waterbird populations have declined around the world as a result of anthropogenic impacts from habitat loss and degradation, direct mortality, reproductive failure, and disturbance from humans and non-native and domestic animals. Specialist species are particularly at risk from changing environmental conditions and disturbances compared to generalist species. Plovers, lapwings, terns, and other waterbird species in the Order Charadriiformes nest on the ground, near water, and in exposed areas with little vegetative cover. As a result of their specialized breeding ecology and habitat requirements, nests of these species are therefore highly vulnerable to animal predation, flooding due to rainfall and hydrologic fluctuations, and disturbance from humans and domestic animals. Different social, economic, and political situations among world regions present distinct opportunities and challenges for implementing species conservation. In this study, I explore breeding ecology and conservation of threatened ground-nesting waterbirds in two different systems: 1) Piping Plovers Charadius melodus that breed on lakeshore beaches in the Great Lakes region of the United States, and 2) a community of six species, including River Tern Sterna aurantia, River Lapwing Vanellus duvaucelii, Great Thick-knee Esacus recurvirostris, Indian Thick-knee Burhinus indicus, Small Pratincole Glareola lactea, and Little Ringed Plover Charadrius dubius, that nest on river sand and gravel bars in the Mekong River basin in Cambodia. First, I examine factors affecting nest survival and renesting, and compare in situ and ex situ management scenarios to evaluate the potential efficacy of egg salvage as a means to augment the Great Lakes Piping Plover population. Second, I investigate factors affecting nest and chick survival of riverine birds in Cambodia, and evaluate the effectiveness of a direct payment nest protection program to improve reproductive success. Third, I examine factors affecting multi-scale habitat selection, and the consequences of habitat selection on reproductive success of riverine birds in Cambodia. This study provides valuable new information that will aid ongoing conservation efforts for threatened ground-nesting waterbirds such as the Piping Plover in North America and riverine birds in Southeast Asia. This work also has implications for conservation of threatened species more broadly.
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    Influence Of Habitat Type On Nest Success, Fledgling Survival, Predator Abundance, And Post-Fledging Habitat-Use Of The Golden-Winged Warbler In Northern Minnesota
    (2024-04) Howland, Brett
    The Golden-winged Warbler (Vermivora chrysoptera) is one of the most critically threatened birds in North America with a global population estimated at only 400,000 individuals of which 50% nest in Minnesota. The species relies on two distinct habitat types, shrub wetland and young forests, for breeding. Quantifying differences in demographic parameters, such as productivity and survival, between habitats is necessary to inform conservation efforts and ensure long-term population stability and growth. To better understand the breeding ecology of Golden-winged Warblers, we studied their nest success, post-fledging survival, and post-fledging habitat-use across 10 study sites in northern Minnesota, USA from 2020 to 2023. We monitored a total of 91 nests and tracked the post-fledging movements of 60 individuals from 52 broods. We used these data to determine the influence of vegetation characteristics, habitat, and landscape factors on nest success, fledgling survival, and post-fledging habitat-use. We assessed the effect of habitat type on nest and juvenile survival using a Markov likelihood framework to estimate daily survival rate as well as daily failure probabilities due to predation and weather events. Our results indicated that there was no difference in nest success and fledgling survival between young forests and shrub wetlands. Predation by sciurids, hawks, and mesocarnivores during the nesting period and the post- fledging period was the most common cause of mortality. Nest survival was lowest for nests that were close to forest edges and survival was lower for nests that were initiated later in the breeding season. Fledgling survival was also lower for birds near forest edges but increased as fledglings aged and became more mobile. Results from the habitat selection models indicated that Golden- winged Warbler fledglings used a variety of habitats including young forest stands that have retained trees and shrub wetland habitats; within stands, they select for areas with high shrub/sapling density, canopy cover, and coarse woody debris. Overall, our results showed that forest management activities that promote structural diversity in young forest stands and conservation of shrub wetland habitats is necessary to maintain stable breeding populations of Golden-winged Warblers in the region.
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    Sympatric nesting Eastern Prairie Population Canada geese and lesser snow geese on the Hudson Bay lowlands: Nest survival and spatial distribution.
    (2009-07) Reiter, Matthew Edward
    The distribution and abundance of breeding lesser snow geese ( Chen caerulescens caerulescens ) in northern Manitoba, Canada have expanded considerably during the last 30 years, and snow geese now use areas where they did not previously occur and were traditionally used solely by breeding Eastern Prairie Population (EPP) Canada geese ( Branta canadensis interior ). Breeding and migrating snow and Ross's geese ( Chen rossii ) have dramatically altered sub-arctic vegetation along Hudson Bay, but the direct or indirect effects of these growing populations on other species, particularly sympatric nesting EPP Canada geese, is not well documented. To better understand relationships between snow geese and EPP Canada geese, I evaluated factors influencing survival and spatial distribution of Canada goose nests across a range of spatial and temporal scales. I employed nest distribution data, 2001-2007, and spatial point-pattern analyses to assess (1) whether nesting Canada geese exhibited territoriality, (2) whether current spatial patterns of Canada goose nest distribution were evolutionarily stable, and (3) whether spatial patterns of Canada goose nest fate were associated with the density of nesting snow geese. In addition, I employed logistic-exposure models to evaluate factors influencing within- and among-year variation in the probability of nest survival for Canada goose nests from 2005-2007 in areas with different histories and densities of snow goose nesting. Specifically, I tested the apparent-competition hypothesis and the nesting-association hypothesis as mechanisms to describe interactions between nesting Canada geese and snow geese. I examined factors influencing the spatial distribution of nesting EPP Canada geese in a coastal tundra landscape between 1976 and 2007, and assessed whether associations with these factors have changed in light of changes to the coastal salt marsh vegetation from snow goose herbivory. Lastly, I modeled Canada goose nest count data collected during range-wide aerial breeding population surveys conducted annually for EPP Canada geese in northern Manitoba, Canada, 1987-2008. I employed mixed-effects Poisson regression to (1) quantify spatial relationships between nesting lesser snow geese and Canada geese; (2) assess factors influencing the distribution of nesting Canada geese at a range-wide spatial scale (101,500 km 2 ); and (3) evaluate how well local (i.e., nest or study area) spatial-scale associations predict range-wide distribution patterns. Point-pattern analyses indicated territoriality among nesting Canada geese and that changes in snow goose nest proximity and density may influence Canada goose nest fate. However, logistic-exposure models did not support the apparent-competition or nesting-association hypotheses as mechanisms governing associations among Canada goose nest survival and nesting snow geese; particularly relative to the strong effects of collared lemming ( Dicrostonyx richardsoni ) and arctic fox ( Alopex lagopus ) population dynamics. Canada goose nest density was negatively associated with increasing distance to coastal salt marsh brood-rearing habitat; however, from 1976 to 2007, this relationship appeared to be changing to where in more recent years increased distance to salt marsh was positively associated with density of nesting Canada geese. Three models of Canada goose nest counts from range-wide aerial surveys--all containing factors related to previous Canada goose nest density (representing recruitment), distance to Hudson Bay, general habitat type, and lesser snow goose nest density--had the lowest mean-squared error among all models considered and were unbiased. The relationship between Canada goose nests and snow goose nest density suggested that the abundance of nesting Canada geese and snow geese varied similarly across habitats throughout the entire EPP breeding range (e.g., both abundant near the coast), but that very high snow goose abundance may have negative impacts on Canada goose nest density. My analyses of data from multiple spatial and temporal scales suggested that associations between the distribution of Canada goose nests and nesting snow geese was likely related to alteration of coastal salt marshes from snow goose foraging, and subsequent changes in the distribution of Canada goose brood-rearing habitat use; rather than influences related to Canada goose nest survival. My analyses highlight that a continuing shift in the spatial distribution of nesting snow geese along western Hudson Bay will have implications for the spatial distribution of sympatric nesting Canada geese.