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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Current and Projected Nest Site Availability for Cavity-nesting Waterfowl in the Upper Mississippi River and Great Lakes Region

Denton, John Curtis 01 January 2009 (has links)
Clearing of old growth forests resulted in a substantial loss of nesting habitat for cavity-nesting waterfowl during the late 19th and early 20th centuries. Since then, many hardwood forests have matured into size classes capable of producing cavities suitable for nesting ducks. To quantify changes in cavity availability in U. S. Fish and Wildlife Service Region 3, which contains most of the midwestern U.S., I examined current cavity availability at 4 sites where cavity availability had been estimated in the past; Mingo National Wildlife Refuge (NWR) in Missouri, Shiawassee NWR in Michigan, Mead Wildlife Area (WA) in Wisconsin, and Muscatatuck NWR in Indiana. I found densities of 1.8 ± 0.4, 1.4 ± 0.3, 0.9 ± 0.4, and 1.8 ± 0.4 suitable cavities per hectare at each of these sites, respectively. Suitable cavities per hectare increased at Mingo NWR (433%) since 1966 and Shiawassee NWR (1400%) since 1974, but remained similar at Mead WA and Muscatatuck NWR since the mid-1980's, after accounting for differences in past, study-specific criteria for cavity suitability. Differences among sites were likely due to variation in species composition, stage of forest maturation, timber management, and time elapsed since the previous studies. Comparison of size-class distributions for all trees and for trees with cavities indicated that cavities occur in the largest trees and that forests have yet to mature into the most prolific cavity-producing size classes. This conclusion was corroborated by forest growth modeling results from Forest Vegetation Simulator, a forest growth-modeling program from the USDA Forest Service. I used Forest Inventory and Analysis data to model growth from 2008 to 2058 at 10-year intervals for Region 3. Cavity per tree estimates from the 4 study sites were applied to modeling outputs, and cavity availability was projected to almost double over the entire region by 2058. Thus, the observed and further expected increases in cavity density in the region justify re-examination of nest box programs and possibly a reduction of artificial nest boxes in some areas of the region where sufficient natural cavities exist. Because current and future estimates indicate sufficient nest sites for cavity-nesting waterfowl, efforts should be spent protecting and restoring brood-rearing wetlands, which are known to be declining in many areas of Region 3.
2

Nest box use by Common Goldeneye (Bucephala clangula) in the Chena River System, Interior Alaska

Porter, Riley D. 13 August 2024 (has links) (PDF)
Various environmental and demographic factors can influence nest site selection in cavity-nesting birds. Nest site choices may involve females’ familiarity with local habitats or resources, or information gained about the quality of a potential nest site. Common Goldeneyes (Bucephela clangula) are philopatric, yet some proportions of available nest boxes commonly remain vacant during breeding seasons throughout the birds’ range. As part of a long-term (1997-2022) study of Common Goldeneyes, I monitored 150 nest boxes in 2021 and 2022 in the Chena River State Recreation Area, Fairbanks, Alaska. I studied use of nest boxes based on box- and landscape specific habitat characteristics, and long-term trends in nest boxes, such as those used or not used by goldeneyes. Nest boxes that were more visible and proximal to wetland habitats positively influenced use, as did breeding population size, recent success, time since the last depredation event, and egg parasitism rates.
3

Posílení populace hohola severního (Bucephala clangula) pomocí umělých budek / Increasing of density of the goldeneye population (\kur{Bucephala clangula}) by using artificial nest boxes

SKLÁŘOVÁ, Kateřina January 2016 (has links)
In the autumn 2013 were set up 50 nest boxes for increasing of density of the Common Goldeneye population (Bucephala clangula) in Třeboň region. The main objectives of this study were to check the nest boxes after breeding season and analyse the results. These nest boxes were checked in the July 2014 and 2015. In the spring 2015 were set up 2 mobile scouting cameras to the selected nest boxes. There was also monitor the occurrence of the Common Goldeney on the Naděje fishpond system and Prátr fishpond system by counting. The Naděje fishpond system is created by 16 different sized fishponds and it is situated approximately 8.5 km to the south of the town Veselí nad Lužnicí. The Prátr fishpond system is situated approximately 1 km to the south of the town Třeboň and it is created by 9 fishponds. The monitor was realised in term from 17. 3. 2015 to 27. 7. 2015. The other species of water birds were also counted. In the year 2014 10 nest boxes were occupied and in the year 2015 17 nest boxes were occupied. The nest boxes which were located on the fishpond´s islands were preferred. Both of the mobile scouting cameras recorded European Pine Marten (Martes martes) devastating the nest. The Common Goldeneye was occurred on the both fishpond systems in 2015. In the year 2015 was observed the female of the Common Goldeneye with 8 ducklings on the Prátr fishpond system.

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