Seabird Management Research Articles

Exposure of an endangered seabird species to persistent organic pollutants: Assessing levels in blood and link with reproductive parameters

Ocean contamination, particularly from persistent organic pollutants (POPs), remains a significant threat to marine predators that occupy high trophic positions. Long-lived procellariform seabirds are apex predators in marine ecosystems and tend to accumulate contaminants. Prolonged exposure to pollutants negatively affects their fitness including reproductive success. Low breeding success may represent a hurdle for the restoration of small and endangered seabird populations, including several highly threatened gadfly petrels. Here we investigated the annual variation (2019 and 2022) in organochlorine pesticide (OCP), polychlorinated biphenyl ether (PCB), polybrominated diphenyl ether (PBDE), and polycyclic aromatic hydrocarbon (PAH) exposure in the endangered Bermuda petrel (Pterodroma cahow), and the relationship between female contaminant burden and breeding parameters. We found that petrels were exposed to a wide range of pollutants (33 out of 55 showed measurable levels) with PCBs dominating the blood contaminant profiles in both years. Only 9 compounds were detected in >50 % of the birds. Specifically, among OCPs, p, p’-DDE and hexaclorobenzene were the most frequently detected while fluorene and acenaphthene were the most common PAH. The concentrations of ∑5PCBs and ∑7POPs were higher in older birds. Furthermore, females with greater contaminant burdens laid eggs with a lower probability of hatching. However, female investment in egg production (size and volume) was unrelated to their blood contaminant load. Overall, this study highlights the presence of a wide range of contaminants in the petrel's food web, and it sheds light on the potential impact of chronic exposure to sub-lethal levels of PCBs on the breeding success of seabirds. We claim that toxicological testing should be a practice integrated in the management of seabirds, particularly of endangered species to monitor how past and present anthropogenic activities impact their conservation status.

Conservation of the surface-nesting Kermadec Petrel Pterodroma neglecta neglecta in the South Pacific: clarifying breeding ecology and the threat of avian ground predators

Summary Understanding population dynamics and impacts on island ecology remain top priorities for the conservation management of seabirds, particularly when attempting species-recovery for island restoration. Identifying suitable nesting habitat is a keystone detail in seabird restoration which can be complicated when predator pressures impact colony productivity and population viability. The surface-nesting Kermadec Petrel Pterodroma neglecta neglecta is dispersed on remote islands through the tropics and subtropics. We examined their breeding ecology on Phillip Island, Norfolk Group in the South Pacific and considered the limitations to re-establishment at their previous breeding location on Lord Howe Island (900 km south-east). On Phillip Island, the petrels were mostly monogamous with nesting locations generally within the vicinity of the previous season’s attempts. Breeding sites were limited to sloping terrain 182–228 m above the shoreline and up to 85 m from the coast in small sub-colonies under low scrubby woodland. Based on observations of 56 pairs and data gleaned from Global Light Sensing devices, we determined that breeding (incubation and provisioning) occurs in all calendar months of the year, with a laying peak in the late austral spring. Breeding success in the first year of study was 25% but improved to 56% once management of Purple Swamphens Porphyrio melanotus was implemented. Successful nests were located at sites with naturally limited egress from cleared or lightly vegetated areas. Prudent management of the petrel population on Phillip Island could aid in the regional recovery of the species and, in the process, assist the island’s restoration by significantly increasing transfers of marine-derived nutrient. Their reintroduction to Lord Howe Island is also possible but will likely rely upon consistent productivity of the Phillip Island population for founding immigrants. Moreover, successful establishment will require adaptive management of selected sites to ensure native avian predators do not overly impact breeding.

Complex population structure of the Atlantic puffin revealed by whole genome analyses

The factors underlying gene flow and genomic population structure in vagile seabirds are notoriously difficult to understand due to their complex ecology with diverse dispersal barriers and extensive periods at sea. Yet, such understanding is vital for conservation management of seabirds that are globally declining at alarming rates. Here, we elucidate the population structure of the Atlantic puffin (Fratercula arctica) by assembling its reference genome and analyzing genome-wide resequencing data of 72 individuals from 12 colonies. We identify four large, genetically distinct clusters, observe isolation-by-distance between colonies within these clusters, and obtain evidence for a secondary contact zone. These observations disagree with the current taxonomy, and show that a complex set of contemporary biotic factors impede gene flow over different spatial scales. Our results highlight the power of whole genome data to reveal unexpected population structure in vagile marine seabirds and its value for seabird taxonomy, evolution and conservation.

Captive husbandry and veterinary care of seabirds during the MV Rena oil spill response

Abstract ContextSeabirds were the most common taxa captured alive as part of the oiled wildlife response to the grounding of the container vessel MV Rena in the Bay of Plenty, New Zealand. AimsTo describe the management of seabirds during the spill response, to outline the common problems encountered and to make recommendations for future responses. MethodsSeabirds were collected from 7 October 2011 to 14 January 2012. They were stabilised and underwent pretreatment, washing and rinsing procedures to remove oil, followed by swimming physiotherapy to restore waterproofing and long-term housing in outdoor aviaries. The birds were released in batches close to the original sites of capture once the wild habitat was cleaned. Key results428 live seabirds were admitted. There were two temporal peaks in admissions associated with the ship grounding and when the ship broke up. The majority of live birds were little penguins (Eudyptula minor; 394/428, 92%). Most seabirds admitted (393/428, 91.8%) were contaminated with heavy fuel oil, with the remainder (35/428, 8.2%) found unoiled but starving and/or exhausted or with injuries. Little penguins had lower mortality during rehabilitation (28/394, 7.1%) than other seabird species combined (27/34, 79.4%). Seabirds in poorer body condition on arrival had higher mortality, and unoiled birds were also more likely to die than oiled birds. In oiled little penguins, the degree of oiling on the plumage ranged from 1 to 100%, but mortality was not significantly associated with the degree of oiling (P=0.887). Pododermatitis affected 66% of little penguins. The most common causes of death (n=45) included weakness, anaemia and hypothermia in oiled seabirds (16/45, 35.6%), and starvation and weakness in unoiled seabirds (14/45, 31.1%). ConclusionsTotal survival to release was 87.1%, primarily influenced by the species involved and the body condition of the birds on arrival. Unoiled seabirds had higher mortality rates than oiled seabirds. ImplicationsOiled wildlife can be rehabilitated with good success, even when heavily oiled, or to a lesser extent, when found in poor body condition. More work is needed to refine species-specific rehabilitation protocols for seabirds, especially for those being admitted in emaciated body condition.

Metals in Feathers of African Penguins (Spheniscus demersus): Considerations for the Welfare and Management of Seabirds Under Human Care.

Bird feathers have been proven to be reliable indicators of metal exposure originating from contaminated food and polluted environments. The concentrations of 15 essential and non-essential metals were investigated in African penguins (Spheniscus demersus) feathers from a Northwestern Italian zoological facility. These birds are exclusively fed with herring from the northeast Atlantic Ocean. Certain elements, such as Hg and Cd, reflected the bioaccumulation phenomena that occur through the marine food chain. The levels of Cr, Mn, and Ni were comparable to those registered in feathers of birds living in polluted areas. These results are important for comparative studies regarding the health, nutrition and welfare of endangered seabirds kept under human care.

Habitat selection of foraging chick-rearing European shags in contrasting marine environments

Impacts of anthropogenic activities on coastal seabirds might be extensive, especially in the breeding season. Identifying important foraging areas and associated habitats is important for a proper management of seabirds. To identify habitat characteristics driving the selection of foraging sites of breeding European shags Phalacrocorax aristotelis, this study used tracking data (GPS- and TDR-loggers), from 282 individual birds comprising 905 foraging trips and 27,303 dives with known locations, to create habitat selection models. To explore possible effects of regional differences in habitat on foraging behavior, the study was performed at two Norwegian colonies, Sklinna in the Norwegian Sea (65°N, 11°E) and Hornoya in the Barents Sea (70°N, 31°E), with distinct differences in seascape structure and habitat availability. Shags at Sklinna foraged further away from the colony than those at Hornoya but diving depth and duration were similar at the two colonies. In both colonies, sea depth was an important predictor of habitats selected by chick-rearing shags during foraging, with birds preferring shallow depths. At Sklinna, shags also selected for flat areas with high probability of kelp forest occurrence. There was no difference in trip length and duration between sexes, but males dived deeper than females in both colonies. This suggests that males and females might utilize different microhabitats within the same foraging area. The study discusses the application of habitat selection modeling to identify important foraging areas for coastal seabirds, and how this may contribute to the management, conservation and assessment of impacts of human activities.

Seabird mortality induced by land‐based artificial lights

Artificial lights at night cause high mortality of seabirds, one of the most endangered groups of birds globally. Fledglings of burrow-nesting seabirds, and to a lesser extent adults, are attracted to and then grounded (i.e., forced to land) by lights when they fly at night. We reviewed the current state of knowledge of seabird attraction to light to identify information gaps and propose measures to address the problem. Although species in families such as Alcidae and Anatidae can be grounded by artificial light, the most affected seabirds are petrels and shearwaters (Procellariiformes). At least 56 species of Procellariiformes, more than one-third of them (24) threatened, are subject to grounding by lights. Seabirds grounded by lights have been found worldwide, mainly on oceanic islands but also at some continental locations. Petrel breeding grounds confined to formerly uninhabited islands are particularly at risk from light pollution due to tourism and urban sprawl. Where it is impractical to ban external lights, rescue programs of grounded birds offer the most immediate and employed mitigation to reduce the rate of light-induced mortality and save thousands of birds every year. These programs also provide useful information for seabird management. However, these data are typically fragmentary, biased, and uncertain and can lead to inaccurate impact estimates and poor understanding of the phenomenon of seabird attraction to lights. We believe the most urgently needed actions to mitigate and understand light-induced mortality of seabirds are estimation of mortality and effects on populations; determination of threshold light levels and safe distances from light sources; documentation of the fate of rescued birds; improvement of rescue campaigns, particularly in terms of increasing recovery rates and level of care; and research on seabird-friendly lights to reduce attraction.

Combining bird-borne tracking and vessel monitoring system data to assess discard use by a scavenging marine predator, the lesser black-backed gull Larus fuscus

A step-wise reduction of fishery discards in the North Sea may have cascading effects on scavenging seabirds that rely on discards as a food resource. Understanding the interactions between seabirds and fisheries is thus crucial for seabird management and conservation. Using bird-borne GPS loggers, we investigate to what extent incubating lesser black-backed gulls Larus fuscus at Helgoland overlap on a spatio-temporal scale with fishing vessel positions obtained through the vessel monitoring system, as well as the distance around vessels at which birds adopt a non-random search behaviour that is indicative of the utilization of discards. We characterize foraging trips and discuss our findings in view of potential effects of the change of the European discard policy on lesser black-backed gulls. Individuals overlapped on a spatio-temporal scale with fishing vessels inone-third of the foraging trips (17 of 48 trips). Within <5 km of fishing vessels, birds exhibited lower flight speeds and higher path tortuosity values, indicating non-random search behaviour and thus the utilization of discards. To feed on discards, birds travelled greater total distances and spent more time away from the colony than birds feeding on non-discards, which is mainly due to the distant location of fishing grounds from the colony. Our results support previous studies showing the spatio-temporal overlap between birds and fishing vessels and behavioural switching from commuting to foraging. The inferred use of both discards and non-discards highlights the dual feeding strategy in this population, but a long-term reduction in discards may negatively affect the population on Helgoland, if sufficient alternative high-energetic food resources are not available within their foraging range.

A GIS‐based decision‐making approach for prioritizing seabird management following predator eradication

Given that 29% of seabird species are threatened with extinction, protecting seabird colonies on offshore islands is a global conservation priority. Seabirds are vulnerable to non‐native predator invasions, which reduce or eliminate colonies. Accordingly, conservation efforts have focused on predator eradication. However, affected populations are often left to passively recover following eradications. Although seabirds are highly mobile, their life history traits such as philopatry can limit passive recolonization of newly predator‐free habitat. In such cases, seabird colonies can potentially be re‐instated with active restoration via chick translocations or social attraction methods, which can be risky and expensive. We used biogeographic and species‐specific behavioral data in the Hauraki Gulf, New Zealand, a global hotspot of seabird diversity and predator eradications, to illustrate the use of geographic information systems multi‐criteria decision analysis to prioritize islands for active seabird restoration. We identified nine islands with low observed passive recovery of seabirds posteradication over a 50‐year timeframe, and classified these as sites where active seabird management could be prioritized. Such spatially explicit tools are flexible, allowing for managers to choose case‐specific criteria such as time, funding, and goals constrained for their conservation needs. Furthermore, this flexibility can also be applied to threatened species management by customizing the decision criteria for individual species' capacity to passively recolonize islands. On islands with complex restoration challenges, decision tools that help island restoration practitioners decide whether active seabird management should be paired with eradication can optimize restoration outcomes and ecosystem recovery.

Seabirds maintain offspring provisioning rate despite fluctuations in prey abundance: a multi‐species functional response for guillemots in the North Sea

Summary Seabirds that consume more than one prey type may adjust their foraging to maintain provisioning rates for their chicks. How energetically effective are these strategies, and what are the implications for the management of seabirds and their marine habitat? A multi‐species functional response links consumption rates to the availability of multiple prey types, but fitting multi‐species functional responses to field data can be difficult, requiring consumption measurements over a range of different prey abundances. Such detailed data may be especially difficult to obtain in marine ecosystems. We used annual time‐series data on chick provisioning for the common guillemot Uria aalge together with abundance indices for its two main prey (lesser sandeel Ammodytes marinus and sprat Sprattus sprattus) to parameterize a multi‐species functional response for parents provisioning chicks at a major North Sea colony from 1992 to 2005. The fitted model reproduced changes in diet and consumption rate which were consistent with changes in local prey abundance including a long‐term decline in sandeels. The model predicted that energy intake by chicks would be more sensitive to changes in sprat abundance than sandeel abundance. Guillemots appeared able to adjust their foraging tactics over a wide range of prey abundances to maintain a consistent energetic intake rate for chicks. Synthesis and applications. Our results suggest guillemot chicks obtain adequate calorific intake from their parents despite fluctuating prey abundances, conferring some resilience in the face of environmental variation. The parameterized multi‐species functional response model can be used to estimate levels of severe prey shortage that compromise provisioning. It also enables us to interpret predator consumption rates so that these can be used as a metric of prey availability. Further, quantifying trophic links between marine prey and apex predators is needed to support the development of multi‐species models in which the predators can be included. Such models are needed as tools to effectively manage the marine ecosystem, taking into account the objectives of fishing, conservation and the need to maintain Good Environmental Status.

Potential consequences of discard reform for seabird communities

Summary Upcoming reform of the European Union (EU) Common Fisheries Policy will be the biggest change in European fisheries management for a generation. A central plank of this reform is a proposed ban on discards, to aid the creation of economically and environmentally sustainable fisheries. This, together with a global trend for declining discards, may have unforeseen knock‐on consequences for the large number of scavenging seabirds that consume this plentiful subsidy. Discards have shaped many aspects of seabird foraging, distribution and population dynamics. Here, we review these effects and consider the potential for both negative and positive impacts of discard reforms for seabirds, with particular focus on the EU, and propose recommendations for ongoing research and conservation. EU seabird scavengers are dominated by a relatively small number of large generalist taxa. Many of these occur at globally significant numbers within the EU, but may be able to buffer a decline in discards by switching to feed on alternative foods. A discard ban may have negative consequences by creating a food shortage for scavenging birds. Some species may offset this by feeding more on other birds, with potentially negative population‐level impacts, or by moving into novel environments. Benefits of a discard ban may be a reduction in seabird bycatch in fishing gears, as well as a reduction in populations of large generalist species that currently dominate some seabird communities. Synthesis and applications. Reform of the Common Fisheries Policy and global discard declines are essential components towards creating sustainable fisheries, but may have both detrimental and beneficial effects on seabird communities. The nature of these impacts is still poorly understood, highlighting the need for detailed long‐term seabird monitoring, as well as building resilience into populations through policy measures that incorporate remedial action on major seabird conservation priorities. Research should focus on understanding how seabird foraging, in terms of functional responses and searching behaviour, is influenced by both changing discards and natural fish prey availability, and how they impact upon fitness. It is also essential to link individual‐level responses with population‐, community‐ and ecosystem‐level change. Understanding these links is fundamental to ongoing seabird management and conservation, and an ecosystem‐based approach to fisheries management.

Assessing aural and visual cueing as tools for seabird management

AbstractSocial attraction, that is, mimicking of active and productive colonies via audio playback of calls of breeding conspecifics and the use of decoys, is commonly used to attract birds to newly established or restored breeding sites. However, little is known about the relative importance of aural versus visual cues for identify nesting areas. Such information is important for design and evaluation of management protocols. We studied the effectiveness of decoys (visual cues) and playbacks (audio cues) as methods for restoring a colony of common terns (Sterna hirundo) at Muskeget Island, Massachusetts, USA. We used a 2‐year, crossover experiment with 3 treatment areas: audio and visual, audio only, and visual only. We reversed treatment areas in the second year to control for previous nesting area or substrate preference. In both years, nests were built 9–101 m downwind of loudspeakers. There was no overlap in areas used for nesting between years and no nests were built within decoy plots in either year. Behavioral observations showed that birds responded to decoys only when within range of sound treatments. Conspecific vocalizations appear to be important proximate cues for seabird colony site selection and should be given priority in management protocols using social attraction. © 2011 The Wildlife Society.

Optimal foraging in chick-raising Common Guillemots (Uria aalge)

The Norwegian population of the Common Guillemot Uria aalge has declined by >95% since the 1960s, and is classified as critically endangered in the Norwegian Red List. Much of the recent decline has been attributed to reduced food availability, but without extensive documentation of adult diet. Instead, chick diet has been considered a proxy of adult diet during the breeding season in many Norwegian studies. However, central-place foraging theory, especially for single-prey loaders, predicts that this may not be so, and this study directly compares the diet of adult and chick Common Guillemots during the breeding season at a colony in NE Norway. Whereas chicks were fed mainly capelin (Mallotus villosus) and sandeels (Ammodytes sp.), most of the adult diet consisted of the two youngest year classes of Gadidae, probably cod (Gadus morhua) and haddock (Melanogrammus aeglefinus). A successful ecosystem management of seabirds is dependent on a full understanding of how prey quality, abundance and availability influence seabird populations and their viability, such that knowing the true diet of adult Common Guillemots has important implications in the modelling and management of the Norwegian populations.

Changing Seabird Management in Hawai'i: from Exploitation through Management to Restoration

Fossil evidence indicates that diverse and abundant seabird communities were once found in the main Hawaiian Islands. However, these seabird populations have severely decreased, or even disappeared, as a result of human disturbance, habitat loss and predation from introduced mammals. Today, the vast majority of Hawai'i's seabirds nest on low-lying and uninhabited atolls in the Northwestern Hawaiian islands, some of which will not be able to withstand projected sea-level rises. As a result, populations of many seabird species will be further reduced unless suitable nesting habitat in the main Hawaiian Islands can be restored against predators.The history of seabird management in the Hawaiian Islands is examined, tracing three overlapping stages. The first emphasized exploitation, the second recognized the damage done by humans and developed methods to remove the causes. The third and current stage focuses on restoration, initially of seabirds, and most recently of ecosystems. Restoration will require a scientific approach and documentation of successes and failures, improving the chances of success for future interventions.

Understanding and addressing seabird bycatch in Alaska demersal longline fisheries

The incidental catch of seabirds in longline fisheries is a global conservation concern. In Alaska, annual seabird bycatch in demersal longline fisheries ranged between 10,300 and 26,300 birds (1995–2001). We explore the relationship between four categories of potential forcing factors (temporal, spatial, environmental, and fisheries-related) and seabird bycatch rates in Alaska demersal longline fisheries to provide practical management alternatives that could significantly reduce seabird bycatch. Separate generalized linear or additive models (GLM or GAM, respectively) were created for several combinations of seabird group, fishery and large geographic region. Across nearly all models, “vessel” was the most influential factor explaining seabird bycatch rate variation. Rather than a single variable, vessel is an amalgam of unmeasured forcing factors many of which could not be separated out in this data set (e.g., longline sink rate, vessel setting speed, line deployment location relative to propeller direction). A separate vessel-specific analysis also supported the multivariate results that performance of an individual vessel is overwhelmingly important (i.e., some vessels have consistently high or low bycatch rates from year to year). Therefore, vessel-specific performance is a critical management option. The effects of temporal (annual, month, and breeding phenology) and spatial variables were also moderately influential on seabird bycatch rates. Our results suggest that seasonal adjustments in the Alaska longline fishery have potential for overall bycatch reductions, but vague seabird management objectives could have huge unintended and undesirable consequences when implementing temporal adjustments. Other variables (environmental and other fishing-related factors) were frequently significant but contributed a small amount to overall explained deviance. Based on this study, we conclude that a vessel-specific management approach would be the most effective and efficient means to reduce seabird bycatch in Alaska.

APPLICATION OF TRACKING AND DATA-LOGGING TECHNOLOGY IN RESEARCH AND CONSERVATION OF SEABIRDS

The Auk A Quarterly Journal of Ornithology Vol. 125 No. 2 April 2008 The Auk 125(2):253–264, 2008  The American Ornithologists’ Union, 2008�� Printed in USA. Perspectives in Ornithology Application of Tracking and Data-logging Technology in Research and Conservation of Seabirds A lan E. B urger 1,3 and S cot t A. S haffer 2,4 Department of Biology, University of Victoria, Victoria, British Columbia V8W 3N5, Canada; and Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California 95060-5730, USA Seabirds are the most conspicuous and mobile of all pe- applications, illustrate the roles that seabirds might play in mon- lagic marine organisms. Because most species breed colonially, itoring this watery planet, and discuss the application of new researchers can study statistically large technology in the conservation and samples with relative ease. These attri- management of seabirds. We focus butes have long made seabirds valuable here on La Grangian approaches, . advances in electronic for interpreting conditions in the sur- concerned with a sequence of data technology have greatly changed rounding oceans (Furness and Cam- values at points occupied by an in- phuysen 1997, Boyd et al. 2006, Piatt et dividual organism (Schneider 1994), the way we study seabirds, al. 2007). Until recently, such studies in contrast to studies of populations were usually based on data obtained or communities made at colonies or providing unprecedented insights at breeding colonies or from vessels, from vessels or aircraft. into their locomotion, physiology, but in the past two decades, advances in electronic technology have greatly A dvancing T echnology foraging behavior, migration, changed the way we study seabirds, demographics, and exposure to providing unprecedented insights into The burgeoning market for consumer their locomotion, physiology, foraging electronics and communication (e.g., anthropogenic risks at sea.” behavior, migration, demographics, satellite and cell-phone communica- and exposure to anthropogenic risks at tion) is partly responsible for the ad- sea. In oceans that are rapidly chang- vances and miniaturization of sensors, ing as a result of human activities and global climate change, this memory storage, and batteries that are revolutionizing marine or- information from tagged birds is timely and essential for developing nithology (see reviews in Wilson et al. 2002a, Ropert-Coudert and conservation and management strategies for such wide-ranging or- Wilson 2005). We review some recent developments, focusing on ganisms. In addition, seabirds are increasingly being viewed as tools devices that tell us where birds go (satellite tracking, geolocators, for oceanography and climatology—capable of providing essential global positioning system [GPS] loggers, and depth recorders) and physical and biological information on the sea itself. what they are doing (sensors coupled with data loggers). Here, we highlight some of the exciting new techniques Tracking devices.—Before 1990, conventional VHF radio tags and data that are emerging, discuss some current and future were used to monitor colony attendance and near-colony foraging E-mail: aburger@uvic.ca Department of Biology, California State University, San Bernardino, California 92407, USA. The Auk, Vol. 125, Number 2, pages 253–264. ISSN 0004-8038, electronic ����������������  2008 by The American Ornithologists’ Union. All rights reserved. Please ISSN������������ direct all requests for permission to photocopy or reproduce article content through the University of California Press’s Rights and Permissions website, http://www. ucpressjournals.com/reprintInfo.asp DOI: 10.1525/auk.2008.1408

Ecology, Conservation, and Management of Seabirds

Ecology, Conservation, and Management of Seabirds