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

During the summer of 2008 and 2009, we studied the ecology of the Kittlitz’s Murrelet (Brachyramphus brevirostris), a small diving seabird and candidate for the U.S. Endangered Species List, in Prince William Sound (PWS), Alaska. At-sea survey data suggests that the population significantly increased from 2001 to 2009, however there is limited evidence of reproductive success. Habitat use models showed individuals were observed in shallower waters, closer to glaciers, the shoreline, and further from moraines than the available habitat during the daytime. Finer extent sampling from 2008 suggests temperature-depth profiles also influence Kittlitz’s Murrelet daytime habitat use. The associations between Kittlitz’s Murrelets and water column characteristics are likely an effect of prey availability. Stable isotope work in 2009 suggests birds were generalist foragers prior to the breeding season, becoming more specialized following the breeding season. This specialization may have been a response to strict foraging constraints during the flightless fall molt. Time budgets of radio-tagged individuals suggest birds may have been responding to ephemeral prey concentrations, and working near their maximum energetic limits. Remote monitoring of radio-tagged individuals showed birds left the glacial fjord system during the nighttime, possibly spending these hours near gillnet fishing areas, suggesting a new possible area of concern in evaluating potential threats to Kittlitz’s Murrelet populations.

The Kittlitz's murrelet (Brachyramphus brevirostris) is a rare member of the seabird family Alcidae that breeds in coastal areas of Alaska and Beringian Russia. The species belongs to the genus Brachyramphus, an unusual seabird taxon in which all three extant species nest non-colonially, situating their nests up to 75 km inland from coastal marine waters. This nesting strategy is different from that of most seabird species, which tend to nest colonially on remote islands or sea cliffs, where terrestrial predators are generally absent or cannot easily access nests. Within the genus Brachyramphus, Kittlitz's murrelet is notable because a majority of the global population appears to nest on the surface of the ground in rocky alpine habitat near inland or tidewater glaciers, foraging in adjacent marine waters influenced by glacial outflows. The unusual nesting habits of Kittlitz's murrelet have made the study of its nesting ecology difficult, and gaps therefore exist in our understanding of the species' breeding biology. Kittlitz's murrelet populations have declined substantially in core areas of its range, causing the U. S. Fish and Wildlife Service to designate the species as a candidate for protection under the Endangered Species Act. A better understanding of Kittlitz's murrelet nesting ecology is crucial for determining potential causes of these declines and for future management of the species. To this end, I studied Kittlitz's murrelet breeding ecology and nest site selection during 2008-2011 on Kodiak Island, Alaska, in an unglaciated area that was recently found to have large numbers of accessible nests. I and my colleagues found 53 active Kittlitz's murrelet nests in inland scree-dominated habitats and placed remote, motion-sensing cameras at 33 nests. Adults exchanged incubation duties at the nest every 24 or 48 h, almost exclusively during early morning twilight. Following hatching of eggs, parents provisioned their single nestling with an average of 3.9 to 4.8 fish per day, depending on the year. Parental visits to the nest during chick-rearing occurred primarily after sunrise in the early to mid-morning hours, and during evening twilight. Fish were delivered singly to the chick, and Pacific sand lance (Ammodytes hexapterus), a high-lipid forage fish, accounted for about 92% of all identifiable chick meal deliveries. Chick growth rates were high relative to confamilial species, consistent with the high quality of chick diets; the logistic growth rate constant (K) was 0.291, greater than that for any other semi-precocial alcid. Chicks fledged an average of 24.8 d after hatching and asymptotic chick body mass averaged about 135.5 g, approximately 58% of adult body mass. Age at fledging, asymptotic chick body mass (% adult mass), and the number of meal deliveries required to fledge a chick were all lower than or as low as any other species of semi-precocial alcid. The average estimated nest survival rate during 2008-2011 was 0.093 (95% CI = 0.01–0.30), which is extremely low compared to other species in the family Alcidae, and is almost certainly insufficient to sustain a stable population. The primary causes of nest failure were depredation (47% of total nest fates), mostly by red foxes (Vulpes vulpes), and unexplained nestling mortality on the nest (21% of nest fates). Saxitoxin and/or pathogenic endoparasite burdens were observed in five of six necropsied chick carcasses, suggesting possible causes for chick mortality not directly attributable to predation. Habitat characteristics of Kittlitz's murrelet nest sites differed significantly from unused sites at several scales. At a small scale (within 5 m of the nest), nest sites had a lower percent coverage of vegetation and higher percent coverage of intermediate-sized rocks (5–30 cm diameter), compared to randomly selected unused sites. Nest sites were also located on steeper, more north-facing slopes compared to randomly selected sites. Nest sites also had a lower percent coverage of vegetation than randomly-selected sites at larger scales (within 25 m and 50 m of the nest site). Nest sites were located significantly farther from the edge of densely-vegetated habitats than random sites. There was no evidence that nest sites were different from randomly-selected sites in terms of elevation, proximity to ridgelines, or proximity to the open ocean, although a low degree of variation within the study area for these habitat characteristics may have precluded detection of potential differences. Nest survival rates did not co-vary with slope, percent vegetation coverage, distance from vegetated edges, or percent cover of intermediate-sized rocks; however, this result may be an artifact of a limited sample size. The results of this thesis will provide managers with a better understanding of the factors that may limit Kittlitz's murrelet nesting success, such as nest predation and forage fish availability, as well as factors that may influence the quality and distribution of Kittlitz’s murrelet nesting habitat in the future, given on-going and progressive climate change. / Graduation date: 2013

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.