Iain Stenhouse

The Kittlitz's Murrelet Brachyramphus brevirostris is a poorly known alcid of the Bering Sea region. It is one of the rarest breeding seabirds in the North Pacific and is listed as Critically Endangered on the IUCN Red List. It has a highly restricted breeding range, with a patchy distribution in Alaska and the Russian Far East. In this paper, we highlight its use of the Kodiak Archipelago, Alaska - an area that has received little research or monitoring attention as breeding or wintering habitat for this species. Based on observational data from the last 30+ years, we conclude that Kittlitz's Murrelets are present year round in the area and we present maps of their distribution around the archipelago. We include a description of the location and habitat characteristics of the first confirmed case of Kittlitz's Murrelet breeding on Kodiak Island and map potential nesting habitat across the archipelago. Given the conservation status and increasingly high profile of this s...

The study of long-distance migration provides insights into the habits and performance of organisms at the limit of their physical abilities. The Arctic Tern Sterna paradisaea is the epitome of such behavior; despite its small size (<125 g), banding recoveries and at-sea surveys suggest that its annual migration from boreal and
high Arctic breeding grounds to the Southern Ocean may be the longest seasonal movement of any animal. Our tracking of 11 Arctic Terns fitted with miniature (1.4-g) geolocators revealed that these birds do indeed travel huge distances (more than 80,000 km annually for some individuals). As well as confirming the location of the main wintering region, we also identified a previously unknown oceanic stopover area in the North Atlantic used by birds from at least two breeding populations (from Greenland and Iceland). Although birds from the same colony took one of two alternative southbound migration routes following the African or South American coast, all returned on a broadly similar, sigmoidal trajectory, crossing from east to west in the Atlantic in the region of the equatorial Intertropical Convergence Zone. Arctic Terns clearly target regions of high marine productivity both as stopover and wintering areas, and exploit prevailing global wind systems to reduce flight costs on long-distance commutes.

We studied the reproductive biology of Sabine’s Gulls (Xema sabini) breeding on Southampton Island, in the eastern Canadian Arctic, from May to August in 1998 and
1999, and compared our results to information collected from the same region in 1980. Breeding phenology was 10 days earlier in 1998 than in these other years, and reflects an earlier onset of snowmelt in that year. Nests were dispersed, with a density of 7.6 to 8.7 nests per km2. Sabine’s Gulls exhibited strong interannual fidelity to breeding sites. Mean clutch size was lower in 1999 than 1998, and lower in both these years than in 1980. Hatching success was 63% in 1998, but only 21% in 1999 due to increased predation, most likely by arctic fox (Alopex lagopus). Adult gulls and chicks abandoned nest-sites within a few hours of the hatching of the last chick and relocated to coastal ponds, where adults continued to attend chicks. In comparisons of the reproductive biology of Sabine’s Gull to closely related ‘‘tern-like’’ gull species and other ‘‘black-headed’’ gulls, Sabine’s Gull showed a number of distinct ecological and behavioral differences and represents an ecological outlier within the Laridae.

The hippocampal and telencephalon volumes of the nocturnal Leach’s storm-petrel (Oceanodroma leucorhoa, n = 15) were compared with published data for food-storing and non-storing Passerines. The hippocampus to telencephalon ratio of Leach’s storm-petrels is intermediate between food-storing and non-storing birds. Leach’s storm-petrels taken from nesting burrows in wooded habitat had a larger relative hippocampal volume than those taken from burrows in an open meadow. Relative olfactory volume did not differ between woods and open-nesting storm-petrels. The larger relative hippocampal volume of storm-petrels may be associated with increased spatial demands of returning to their nests at night in the darker, more navigationally complex woods. It is not known whether the larger hippocampus in storm-petrels from the woods is due to selection on different subpopulations or whether experience in a more complex environment results in greater hippocampal volume. Hippocampal volume from the brain of one diurnal Procellariiforme, the northern fulmar (Fulmaris glacialis), fell within the range of non-storing species, which supports the view that hippocampal enlargement in the storm-petrel is related to the spatial demand of returning to the nest at night.

Forage fishes are a critical food web link in marine ecosystems, aggregating in a hierarchical patch structure over multiple spatial and temporal scales. Surface‐level forage fish aggregations (FFAs) represent a concentrated source of prey available to surface‐ and shallow‐foraging marine predators. Existing survey and analysis methods are often imperfect for studying forage fishes at scales appropriate to foraging predators, making it difficult to quantify predator–prey interactions. In many cases, general distributions of forage fish species are known; however, these may not represent surface‐level prey availability to predators. Likewise, we lack an understanding of the oceanographic drivers of spatial patterns of prey aggregation and availability or forage fish community patterns. Specifically, we applied Bayesian joint species distribution models to bottom trawl survey data to assess species‐ and community‐level forage fish distribution patterns across the US Northeast Continental Shelf (NES) ecosystem. Aerial digital surveys gathered data on surface FFAs at two project sites within the NES, which we used in a spatially explicit hierarchical Bayesian model to estimate the abundance and size of surface FFAs. We used these models to examine the oceanographic drivers of forage fish distributions and aggregations. Our results suggest that, in the NES, regions of high community species richness are spatially consistent with regions of high surface FFA abundance. Bathymetric depth drove both patterns, while subsurface features, such as mixed layer depth, primarily influenced aggregation behavior and surface features, such as sea surface temperature, sub‐mesoscale eddies, and fronts influenced forage fish diversity. In combination, these models help quantify the availability of forage fishes to marine predators and represent a novel application of spatial models to aerial digital survey data.

The Mid-Atlantic Baseline Studies Project helped address environmental barriers to offshore wind energy development in the mid-Atlantic region by providing regulators, developers, and other stakeholders with comprehensive baseline ecological data and analyses. Project funders and collaborators from a range of academic institutions, non-governmental organizations, federal agencies, foundations, and private companies came together to study bird, sea turtle, and marine mammal distributions, densities, and movements on the mid-Atlantic Outer Continental Shelf between 2012 and 2014. Specific project activities and goals included the following: (1) Conduct standardized surveys to quantify bird, sea turtle, and marine mammal densities seasonally and annually throughout the study region and identify important habitat use or aggregation areas. (2) Develop statistical models to help understand the drivers of wildlife distribution and abundance patterns. (3) Use individual tracking data for several focal bird species to provide information on population connectivity and individual movements that is complementary to survey data. (4) Identify species that are likely to be exposed to offshore wind energy development activities in the mid-Atlantic study area. (5) Develop U.S.-based technological resources and assessment methods for future monitoring efforts, including a comparison of high resolution digital video aerial surveys to boat-based surveys. (6) Help meet data needsmore » associated with National Environmental Policy Act (NEPA), Marine Mammal Protection Act, and Endangered Species Act requirements, by contributing several years of data and analysis towards future Environmental Impact Statements. This report consists of six parts: Project overview (executive summary and Chapters 1-2); Examining wildlife distributions and relative abundance from a digital video aerial survey platform (Chapters 3-6); Examining wildlife distributions and abundance using boat-based surveys (Chapters 7-12); Integrating data across survey platforms (Chapters 13-19); Individual movements and habitat use for focal bird species (Chapters 20-25); and Nocturnal avian migration monitoring (Chapters 26-27). Boat-based and digital video aerial surveys each had specific advantages and disadvantages, but were largely complementary (Chapters 1, 5, 13-14). Digital aerial surveys were particularly useful for covering offshore areas at broad scales, where general distributions of taxonomic groups were a priority; boat surveys could provide more detailed data on species identities and behaviors, but were more limited in geographic scope due to their slower survey pace. The mid-Atlantic study area was important for wintering and breeding taxa, and its location also made it a key migratory corridor. There was considerable variation in species composition and spatial patterns by season, largely driven by dynamic environmental conditions (Chapters 12, 15, and 20-22). Habitat gradients in nearshore waters, however, were reliable influences on productivity and patterns of species distributions and abundance. Areas within about 30-40 km of the coast offshore of the mouths of Chesapeake and Delaware Bays, as well as to the south of Delaware Bay along the coast, were consistent hotspots of abundance and species diversity, regardless of survey methodology or analytical approach (Chapters 2, 12, 17). Inter-annual variation was substantial, and the importance of certain environmental variables in predicting animal distributions indicates that these species may well respond to future environmental shifts brought about by anthropogenic effects and climatic change. This study is an important first step, however, towards understanding how bird, marine mammal, and sea turtle populations in the mid-Atlantic may be exposed to offshore wind energy development and other anthropogenic activities. The results of this study provide insight to help address environmental permitting requirements for current and future offshore development projects, and serve as a starting point for more site-specific studies, risk analyses, and evaluation of potential measures to avoid and minimize those risks.« less

Suggested citation: Adams EM, Stenhouse IJ, Gilbert AT, Williams KA, Montevecchi WA. 2015. Using state-space models to identify areas of persistent winter activity and their associated environmental covariates in Northern Gannets. In: Wildlife Densities and Habitat Use Across Temporal and Spatial Scales on the Mid-Atlantic Outer Continental Shelf: Final Report to the Department of Energy EERE Wind &amp; Water Power Technologies Office. Williams KA, Connelly EE, Johnson SM, Stenhouse IJ (eds.) Award Number: DE-EE0005362. Report BRI 2015-11, Biodiversity Research Institute, Portland, Maine. 19 pp.

Between 1996 and 2000, a probable Common Guillemot (Uria aalge) x Razorbill (Alca torda) hybrid was observed periodically among breeding Common Guillemots on Great Island, Newfoundland, Canada. Although the overall body shape and size of this individual were comparable to those of a Common Guillemot, it possessed traits that appeared intermediate between the Common Guillemot and the Razorbill. We suggest that hybridisation between these two auks may occur, albeit rarely, as a consequence of their extensive overlap in breeding range and close proximity within breeding colonies.

As offshore wind energy development is planned in the United States, there is an increasing need for preand post-construction monitoring plans to be focused on species determined to be most vulnerable to hazards of a speci c project. We propose a conceptual model that incorporates biological and sociological parameters. Speci cally, we suggest that demographic, ethological/biological, and population sensitivity be considered with legal protection, economic importance, and/or stakeholder interest. We recommend that vulnerability determinations include qualitative and quantitative methods.

The conservation of migratory marine species, including pelagic seabirds, is challenging because their movements span vast distances frequently beyond national jurisdictions. Here, we aim to identify important aggregations of seabirds in the North Atlantic to inform ongoing regional conservation efforts. Using tracking, phenology, and population data, we mapped the abundance and diversity of 21 seabird species. This revealed a major hotspot associated with a discrete area of the subpolar frontal zone, used annually by 2.9–5 million seabirds from ≥56 colonies in the Atlantic: the first time this magnitude of seabird concentrations has been documented in the high seas. The hotspot is temporally stable and amenable to site‐based conservation and is under consideration as a marine protected area by the OSPAR Commission. Protection could help mitigate current and future threats facing species in the area. Overall, our approach provides an exemplar data‐driven pathway for future conservat...

Mercury (Hg) pollution remains a concern to Arctic ecosystems. The objective of this study was to identify factors influencing Hg concentrations in Arctic-breeding shorebirds and highlight regions and species at greatest risk of Hg exposure. We analyzed 2,478 blood and feather samples from 12 shorebird species breeding at nine sites across the North American Arctic during 2012 and 2013. Blood Hg concentrations, which reflect Hg exposure in the local area in individual shorebirds: 1) ranged from 0.01–3.52 µg/g, with an overall mean of 0.30 ± 0.27 µg/g; 2) were influenced by species and study site, but not sampling year, with birds sampled near Utqiaġvik, AK, having the highest concentrations; and 3) were influenced by foraging habitat at some sites. Feather Hg concentrations, which reflected Hg exposure from the wintering grounds, were generally higher than blood, ranging from 0.07–12.14 µg/g in individuals, with a mean of 1.14 ± 1.18 µg/g. Feather Hg concentrations were influenced b...

Forage fishes are a critical food web link in marine ecosystems, aggregating in a hierarchical patch structure over multiple spatial and temporal scales. Surface-level forage fish aggregations (FFAs) represent a concentrated source of available prey for surface- and shallow-foraging marine predators. Existing survey and analysis methods are often imperfect for studying forage fishes at scales appropriate to foraging predators, making it difficult to quantify predator-prey interactions. In many cases, general distributions of forage fish species are known; however, these may not represent surface-level prey availability to predators. Likewise, we lack an understanding of the oceanographic drivers of spatial patterns of prey aggregation and availability or forage fish community patterns, generally. Specifically, we applied Bayesian joint species distribution models to bottom trawl survey data to assess species- and community-level forage fish distribution patterns across the US Northe...

The Arctic Warbler (Phylloscopus borealis) is a cryptic songbird that uses a Nearctic-Paleotropical migratory strategy. Using geolocators, we provide the first documentation of the migratory routes and wintering locations of two territorial adult male Arctic Warblers from Denali National Park and Preserve, Alaska. After accounting for position estimation uncertainties and biases, we found that both individuals departed their breeding grounds in early September, stopped over in southeastern Russia and China during autumn migration, then wintered in the Philippines and the island of Palau. Our documentation of Arctic Warbler wintering on Palau suggests that additional study is needed to document their wintering range. These results suggest that Arctic Warblers may migrate further overwater than previously thought and provide hitherto unknown information on stopover and wintering locations.

A biographical sketch of John Hutton Stenhouse (1865–1931) is provided. This focuses on his contributions to ornithology in Scotland and to Scottish ornithology, most notably through his long association with the Royal Scottish Museum. His involvements with bird migration studies on Fair Isle and his influence on the subsequent development of a permanent bird observatory on the island are discussed

Extreme climate can negatively affect survival through increased physiological demands or by reducing prey availability. This can have significant population-level consequences for organisms with low reproductive rates, such as seabirds. As an Arctic-breeding trans-equatorial migrant, Sabine’s gull (Xema sabini) is exposed to a profound variety of climate regimes during the year. Therefore, its annual survival may be affected by broad-scale teleconnection patterns that influence regional climate variability. We used Program MARK to estimate apparent survival and resighting probabilities from 2007 to 2013 for adult Sabine’s gulls breeding at a High Arctic colony. We then combined capture–mark–recapture data for the High Arctic colony with those previously published from a Low Arctic colony (1998–2002) to examine influences of climate variability on survival. Mean ± standard error apparent survival estimated for the High Arctic colony was 0.90 ± 0.03, similar to that previously report...

The east coast of Newfoundland, Canada, harbours some of the largest Leach&#39;s Storm-Petrel Oceanodroma leucorhoa colonies in the world. In 1997, we estimated the breeding population of Leach&#39;s Storm-Petrels on Great Island, Witless Bay, Newfoundland at 269 765 ± 27 769 (213 866 - 325 664) pairs. This is similar to a previous estimate from 1979 of 252 910. A shift in distribution has occurred with more petrels nesting in forested habitat and fewer in grass shrub meadows in 1997. Gull predation on seabirds has increased in Newfoundland in the 1990s as a response to a variety ofchanges in the marine ecosystem. We estimated that gulls killed 49189 Leach&#39;s Storm-Petrels in 1997. However, in the face of this large kill, the breeding populations does not appear to have substantially declined. Recruitment from other large colonies may be maintaining the breeding population on Great Island.

Upwelling regions are highly productive habitats targeted by wide-ranging marine predators and industrial fisheries. In this study, we track the migratory movements of eight seabird species from across the Atlantic; quantify overlap with the Canary Current Large Marine Ecosystem (CCLME) and determine the habitat characteristics that drive this association. Our results indicate the CCLME is a biodiversity hotspot for migratory seabirds; all tracked species and more than 70% of individuals used this upwelling region. Relative species richness peaked in areas where sea surface temperature averaged between 15 and 20°C, and correlated positively with chlorophyll a, revealing the optimum conditions driving bottom-up trophic effects for seabirds. Marine vertebrates are not confined by international boundaries, making conservation challenging. However, by linking diversity to ocean productivity, our research reveals the significance of the CCLME for seabird populations from across the Atlan...