Thesis (Ph. D.)--Oregon State University, 1998. / Includes bibliographical references (leaves 135-141).

Marbled Murrelets (Brachyramphus marmoratus) are threatened seabirds that are prone to disturbance both at sea and at old-growth forest nesting areas. I examined murrelet behavior and activity patterns in forest and marine ecosystems of Oregon. Diving behavior was studied during the 1995 and 1996 breeding seasons and was compared to predictions from optimal breathing models, which predicted a strong relationship between dive times and preceding pause times. Diving patterns appeared to fit these predictions more in 1996 than 1995 suggesting that diving behavior was affected more by annual changes in environmental conditions than by physiological constraints on breathing and diving as predicted by optimal breathing models. Activity patterns at inland nest sites were monitored on a near-daily basis during three breeding seasons to assess the relationships between activity and both weather and date. Daily activity was highly variable within and among sites and years and I observed greater variability in activity levels than has been previously reported for this species. Activity varied greatly during all portions of the breeding season and analyses revealed that weather and date variates explained little of the variability present. It also appeared that variability in activity during the breeding season was not due entirely to breeding phenology; however, activity of nonbreeding birds attending nesting stands may contribute to daily variability. Inland activity data also were used to assess the feasibility of developing long-term monitoring strategies based on counts of daily detections. I determined how effectively various survey strategies estimated measures of daily mean and standard deviation of detection counts of murrelets within a breeding season. Results indicated that it would be difficult to obtain reliable estimates of murrelet detections with sampling efforts up to 14 days/season. However, estimates of mean and standard deviation for daily detections during a breeding season may be reliably estimated to within ± 50% with similar or less effort. The power of survey strategies to detect annual declines in detections of 25% and 50% were very low and moderate, respectively, except when variability was quite low. / Graduation date: 1999

No description available.

The marbled murrelet (Brachyramphus marmoratus) is a Threatened seabird with very particular nesting requirements. They choose to nest almost exclusively on mossy platforms, provided by large branches or deformities, in the upper canopies of coniferous old-growth trees located within 50 km of the ocean. Due primarily to a loss of this nesting habitat, populations in B.C. have seen significant decline over the past several decades. As such, reliable spatial habitat data are required to facilitate efficient management of the species and its remaining habitats. Current habitat mapping methodologies are limited by their qualitative assessment of habitat attributes and the large, stand-based spatial scale at which they classify and map habitat. This research aimed to address these limitations by utilizing light detection and ranging (lidar) technologies to develop an object-based habitat mapping methodology capable of quantitatively mapping habitat suitability at the scale of an individual tree on Northern Vancouver Island, British Columbia (B.C.). Using a balanced random forest (BRF) classification algorithm and in-field habitat suitability data derived from low-level aerial surveys (LLAS), a series of lidar-derived terrain and canopy descriptors were used to predict the habitat suitability (Rank 1: Very High Suitability – Rank 6: Nil Suitability) of lidar-derived individual tree objects. The classification model reported an overall classification accuracy of 71%, with Rank 1 – Rank 5 reporting individual class accuracies of 90%, 86%, 74%, 67%, and 98%, respectively. Evaluation of the object-based predictive habitat suitability maps provided evidence that this new methodology is capable of identifying and quantifying within-stand habitat variability at the scale of an individual tree. This improved quantification provides a superior level of habitat differentiation currently unattainable using existing habitat mapping methods. As the total amount of suitable nesting habitat in B.C. is expected to continue to decline, this improved quantification is a critical advancement for strategic managers, facilitating improved habitat and species management. / Graduate / 2018-04-07 / 0329 / 0368 / 0478 / gclyde@uvic.ca

Developing cost-effective tools for population monitoring and research is fundamental to wildlife management programs. This is a major challenge for solitary-nesting, secretive seabirds distributed throughout remote areas of Alaska: the marbled murrelet (Brachyramphus marmoratus) and Kittlitz’s murrelet (B. brevirostris). Both species have experienced major population declines in Alaska, which is the centre of the distribution of their global populations. In 2010-2012, I tested the reliability of two new remote-sensing approaches, marine radar surveys and autonomous acoustic monitoring, to assess population size, trends and distributions of Brachyramphus murrelets in the Kodiak Archipelago. The goals were to compare new and existing assessment tools, to identify differences in spatial and temporal patterns of activity by Brachyramphus murrelets at high latitudes, and to make recommendations for integrating remote-sensing methods into existing monitoring programs. Autonomous acoustic sensors provided a reliable index of marbled murrelet abundance at fine spatial scales (2-3 ha forest stands). Detections of marbled murrelet vocalizations by acoustic sensors and human observers were not statistically different across weekly means. Because high temporal replication could be achieved at no extra cost, automated acoustic sampling provided the best seasonal resolution in patterns of murrelet activity. Radar surveys identified a prolonged (150 min) duration of pre-sunrise inland flight activity relative to lower-latitude populations, reflecting the longer duration of twilight at high latitude. A clear trend in seasonal activity, increasing from June to late July, was identified by radar, audio-visual, and acoustic surveys. The strong seasonal increase in activity detected by radar surveys appears to be an important factor to consider in planning population monitoring programs. Radar surveys could not distinguish between Kittlitz’s and marbled murrelets, but identified potentially greater frequency of inland flight by Kittlitz’s murrelets during darkness based on comparisons between sites. Spatial patterns of abundance, estimated by radar counts, were best predicted by combinations of marine and terrestrial habitat variables within 5 km of nesting flyways, including area of steep slopes (45-90˚), area of old-growth forest, and at-sea densities < 200 m from shore in June. The largest murrelet populations occurred in both forested and unforested watersheds with steep topography; indicating that unforested steep slopes appear to be of greater importance to nesting marbled murrelets in Alaska than previously recognized, particularly in areas adjacent to marine productivity hotspots. I recommend that radar sampling protocols be modified for high latitude surveys to begin 2 h before sunrise to accommodate longer activity periods, and that surveys be repeated at similar dates across years to avoid confounding population change with seasonal changes in abundance. I propose integrating new remote-sensing tools into existing monitoring programs to increase power to detect population trends, reduce costs and risks associated with field personnel, and increase capacity for long-term monitoring of murrelet response to environmental change at multiple spatial scales. / Graduate / 0329 / 0472 / jenna.cragg@gmail.com

The marbled murrelet (Brachyramphus marmoratus) is listed as threatened in both Canada and the United States due to logging of old-growth forest stands, their primary nesting habitat. Existing research is primarily focused on this terrestrial aspect of the species’ ecology. Our understanding of their at-sea foraging ecology, however, is limited to broad-scale studies of population abundance and dynamics. In order to further understand the spatial and temporal variations of marbled murrelet at-sea foraging behaviour and habitat use, bi-weekly surveys of marbled murrelets were conducted in Clayoquot Sound, BC, between May 1 and September 1, 2007 and 2008. Data were first analysed using a Getis-Ord Gi* spatial analysis to identify high-use foraging areas. Total marbled murrelet presence was consistent between years, but spatial distribution varied significantly in both years. A subsequent analysis of oceanic environmental variables found that temperature, salinity and phytoplankton densities (measured as chl a) were spatially ubiquitous, with no significant variation in measures across the study area. Chl a levels showed significant temporal variation, though similar trends in marbled murrelet abundance over time in both seasons suggest that phytoplankton levels do not directly affect murrelet presence. Marbled murrelets were also observed foraging within several metres of gray whales (Eschrictius robustus) feeding on epibenthic zooplankton in 2006 and 2008, a previously undocumented relationship. Join count statistics identified significant clustering of murrelets up to 300m from 39 feeding gray whales in 2006, and no association with 5 gray whales in 2008, marking a foraging association conditional on the abundance of both gray whales and their prey, but potentially significant to marbled murrelet survival and fecundity.