Sabina I. Wilhelm

The effects of variable foraging conditions on common murre (Uria aalge) corticosterone concentrations and parental provisioning

This study investigated how total corticosterone concentrations, chick-feeding rates, and adult body mass changed with food availability from 1998 to 2000 in the same individually marked common murres (Uria aalge). Capelin, the main prey species, arrived inshore by the onset of murre chick hatching in 1998 and 1999 (prey match years); whereas in 2000, hatching began approximately 1 week before the capelin arrived inshore to spawn (prey mismatch year). Serum corticosterone concentrations were higher in the same individuals in the prey mismatch year than they were in either of the match years. Birds sampled before peak capelin spawning in the mismatch year had higher corticosterone levels than murres sampled after peak spawning. Murres with higher corticosterone levels had higher chick-feeding rates and less mass loss in the mismatch year (compared to the match year 1999) than birds with lower levels. Corticosterone levels did not differ between birds that had not foraged for at least 12 h (brooded chick overnight) and those that had, suggesting that short-term food deprivation did not affect corticosterone concentrations. Taken together, these findings suggest that the difference between years reflects a baseline shift in corticosterone levels, particularly in the high-quality birds that were able to increase both corticosterone concentrations and foraging effort.

Divorce in common murres ( Uria aalge ): relationship to parental quality

Behavioral precursors of 12 divorces were examined in 30 color-banded pairs of common murres (Uria aalge) over six breeding seasons. Common murres are long-lived seabirds that typically return each year to the same mate and nest site in dense colonies. At least one parent is present continuously from egg lay to chick fledging. Murres, therefore, have considerable opportunities to compare their mates’ parental behavior with that of several familiar neighbors. Previous reproductive success was lower for divorcing birds than for reuniting pairs. As predicted by the better option hypothesis, there were clear ‘choosers’ (seven females and five males) that initiated divorce by moving to a new bird’s site or by courting a new partner at their current site. Choosers improved their reproductive success after the divorce, whereas their previous partners, the ‘victims’ did not. Yearly divorce rates (average 8.2% per year) were significantly correlated with yearly mortality rates. Divorces appear to be opportunistic: pairs divorced after varying numbers of reproductive failures with the immediate precursor usually being the disappearance (death) of a murre from a successful neighboring site. In contrast to the delays experienced by victims, choosers formed new pairs quickly and laid their eggs no later than reuniting pairs. Prior to the divorce, victims fed their chicks less often than choosers, and some engaged in other behaviors that compromised egg or chick survival. These observations suggest that deficiencies in parental behavior were precursors to the divorce. This report is one of the first cases where reproductive failure of divorcing pairs has been linked to deficits in the parental behavior of the subsequent divorce victim.

Re-evaluating the use of beached bird oiling rates to assess long-term trends in chronic oil pollution

The oiling rate (oiled birds/total birds) has become the international standard to analyze beached bird survey data. However, this index may not reliably track long-term changes in marine oil pollution in regions where other activities that kill seabirds vulnerable to oil, such as hunting and gill-netting, are also changing. We compare the oiling rate from beached bird surveys conducted in southeastern Newfoundland between 1984 and 2006 to an alternative approach, namely trends derived from a model examining the linear density of oiled birds (birds/km). In winter, there was no change in the oiling rate since 1984, while in summer oiling rates significantly increased. In contrast, the number of oiled birds/km showed a significant decline in both winter and summer. The discrepancy in these trends was attributed to steep declines in the number of unoiled birds found in both seasons. In winter, the decline in unoiled birds/km was related to a reduction in the legal murre hunt and less onshore winds, while in summer a reduced cod fishery resulting in fewer murres drowning in nets and warming summers may have lead to the decline. The significant declines in oiled birds/km over the past three decades are hopefully an indication of less oil being present in the marine environment. Although oiled bird densities since 2000 have remained relatively low for the region (winter: 0.58 birds/km, summer: 0.27 birds/km), they still exceed densities reported elsewhere in the world.

Mortality of Migratory Birds from Marine Commercial Fisheries and Offshore Oil and Gas Production in Canada

There is an imminent need for conservation and best-practice management efforts in marine ecosystems where global-scale declines in the biodiversity and biomass of large vertebrate predators are increasing and marine communities are being altered. We examine two marine-based industries that incidentally take migratory birds in Canada: (1) commercial fisheries, through bycatch, and (2) offshore oil and gas exploration, development, and production. We summarize information from the scientific literature and technical reports and also present new information from recently analyzed data to assess the magnitude and scope of mortality. Fisheries bycatch was responsible for the highest levels of incidental take of migratory bird species; estimated combined take in the longline, gillnet, and bottom otter trawl fisheries within the Atlantic, including the Gulf of St. Lawrence, and Pacific regions was 2679 to 45,586 birds per year. For the offshore oil and gas sector, mortality estimates ranged from 188 to 4494 deaths per year due to the discharge of produced waters resulting in oil sheens and collisions with platforms and vessels; however these estimates for the oil and gas sector are based on many untested assumptions. In spite of the uncertainties, we feel levels of mortality from these two industries are unlikely to affect the marine bird community in Canada, but some effects on local populations from bycatch are likely. Further research and monitoring will be required to: (1) better estimate fisheriesrelated mortality for vulnerable species and populations that may be impacted by local fisheries, (2) determine the effects of oil sheens from produced waters, and attraction to platforms and associated mortality from collisions, sheens, and flaring, so that better estimates of mortality from the offshore oil and gas sector can be obtained, and (3) determine impacts associated with accidental spills, which are not included in our current assessment. With a better understanding of the direct mortality of marine birds from industry, appropriate mitigation and management actions can be implemented. Cooperation from industry for data collection, research to fill knowledge gaps, and implementation of mitigation approaches will all be needed to conserve marine birds in Canada. RESUME. Dans les ecosystemes marins, le declin de la biodiversite et de la biomasse des grands predateurs vertebres s’accentue a l’echelle globale et les communautes marines subissent de plus en plus de perturbations. Etant donne la situation, il est important de faire des efforts de conservation et de pratiques exemplaires de gestion pour ces ecosystemes. Nous avons examine deux industries du milieu marin qui entrainent des prises accessoires d’oiseaux migrateurs au Canada : 1) la peche commerciale; et 2) l’exploration, le developpement et l’exploitation du petrole et du gaz au large des cotes. Afin d’evaluer l’ampleur et les sources de mortalite, nous avons compile l’information issue de la litterature scientifique, y compris de rapports techniques, et presentons les resultats d’analyses recentes. La peche commerciale etait responsable du plus grand nombre de prises accessoires d’oiseaux migrateurs : les prises accessoires combinees de la peche a la palangre, aux filets maillants et aux chaluts de fond a panneaux dans les regions de l’Atlantique (y compris le golfe du Saint-Laurent) et du Pacifique, s’echelonnaient de 7 579 a 38 798 oiseaux par annee. En ce qui concerne l’industrie petroliere et gaziere extracotiere, les estimations se situaient entre 188 et 4 494 oiseaux morts par annee, en raison de la decharge d’eau souillee qui forme un film d’hydrocarbures, et des collisions avec les plateformes et les navires. Cependant, ces estimations pour le secteur petrolier et gazier marin sont fondees sur de nombreuses premisses non verifiees. En depit de ces incertitudes, nous pensons que la mortalite causee par ces deux industries n’affectera vraisemblablement pas les communautes d’oiseaux marins au Canada, mais que la peche commerciale est susceptible de causer certains effets sur les populations locales. De plus amples recherches et suivis seront necessaires pour : 1) obtenir de meilleures estimations de la mortalite causee par la peche pour les especes vulnerables et les populations pouvant etre affectees a l’echelle locale; 2) determiner Coastal & Freshwater Group, Cawthron Institute, Canadian Wildlife Service, Environment Canada, Cognitive and Behavioural Ecology, Memorial University of Newfoundland, Faculty of Environmental Studies, York University, Wildlife Research Division, Environment Canada, Population Ecology Division, Bedford Institute of Oceanography, Department Fisheries & Oceans Avian Conservation and Ecology 8(2): 4 http://www.ace-eco.org/vol8/iss2/art4/ l’effet des films d’hydrocarbures issus des rejets d’eau souillee, de meme que l’attraction des plateformes et la mortalite qui y est associee (collisions, lumiere et brulures par torcheres), afin d’obtenir de meilleures estimations de la mortalite causee par l’industrie petroliere et gaziere extracotiere; et 3) determiner les impacts associes aux deversements accidentels, qui ne sont pas pris en compte dans notre analyse. Grâce a une comprehension accrue de la mortalite directe des oiseaux marins par l’industrie, des mesures d’attenuation et de gestion appropriees pourront etre instaurees. Afin de conserver les oiseaux marins au Canada, il sera necessaire d’obtenir la cooperation de l’industrie pour la collecte des donnees, la poursuite des recherches destinees a pallier le manque de connaissance et la mise en place de mesures d’attenuation.

Local Survival Rates of Common Murres Breeding in Witless Bay, Newfoundland

The common murre (Uria aalge) is the largest living auk and one of the most abundant marine birds breeding in the north Atlantic and Pacific Oceans (Nettleship and Evans 1985). Humans have a long history of using murres (both common and thick-billed U. lomvia) as an important source of eggs and meat; more recently, murre populations have been threatened by a variety of anthropogenic activities (Ainley et al. 2002). Current pressures on common murre populations in the Northwest Atlantic include legal hunts in Canada and Greenland (Elliot 1991), being killed by chronic oil pollution along the shipping routes off Newfoundland (Wiese and Robertson 2004), and incidental capture in various types of fishing gear (Piatt and Nettleship 1987). The hunt of murres (locally called turrs) in Newfoundland and Labrador, Canada, is unique in North America, as the only nonaboriginal hunt of a seabird. This hunt was retained in the province as part of the terms of joining Canada in 1949 on the basis that the murres were an important winter protein source for rural Newfoundlanders (Elliot 1991). Recent amendments to the Migratory Birds Convention Act make provisions for the Newfoundland and Labrador murre hunt to be regulated as any other game bird harvest in Canada. In spite of harvests and other threats faced by common murres, little demographic information is available for this species outside of Europe (Ainley et al. 2002). The purpose of our study was to estimate local adult survival rates of common murres breeding in a large colony in Newfoundland from 1996–2003. We collected data from a small study plot of marked birds that was monitored as part of in-depth behavioral studies (Wilhelm 2004, Moody et al. 2005). As all marked individuals could be sexed behaviorally, we were able to examine possible sex differences in local survival rates.

Plastic and metal ingestion in three species of coastal waterfowl wintering in Atlantic Canada

Relatively little attention has been paid to the occurrence of anthropogenic debris found in coastal species, especially waterfowl. We examined the incidence of ingested plastic and metal in three waterfowl species wintering in Atlantic Canada: American black ducks (Anas rubripes) and mallards (A. platyrhynchos), two species that use marine and freshwater coastal habitats for foraging in the winter, and common eider (Somateria mollissima), a coastal marine species that feeds on intertidal and subtidal benthic organisms. Plastic was found in the stomachs of 46.1% (6/13) of mallards and 6.9% (6/87) of black ducks, the first report of ingested anthropogenic debris in these species, while 2.1% (1/48) of eider stomachs contained plastic. Metal was found in the stomachs of 30.8% (4/13) of mallards, 2.3% (2/87) of black ducks, and in 2.1% (1/48) of eiders. Our results indicate that species using coastal marine and freshwater environments are exposed to and ingest anthropogenic debris.

Evaluation of seabirds in Newfoundland and Labrador, Canada, as hosts of influenza A viruses.

Abstract Influenza A viruses infect a wide range of hosts, including many species of birds. Avian influenza A virus (AIV) infection appears to be most common in Anseriformes (ducks, geese, and swans) and some Charadriiformes (shorebirds and gulls), but many other birds also serve as hosts of AIV. Here, we evaluated the role of seabirds as hosts for AIV. We tested 3,160 swab samples from 13 seabird species between May 2008 and December 2011 in Newfoundland and Labrador, Canada. We also tested 156 serum samples for evidence of previous infection of AIV in Common Murres (Uria aalge) and Atlantic Puffins (Fratercula arctica). Avian influenza A virus was detected in breeding Common Murres and nonbreeding Thick-billed Murres (Uria lomvia), and Common Murres also had high antibody prevalence (44%). From these findings, combined with other studies showing AIV infection in murres, we conclude that murres are important for the ecology of AIV. For other species (Razorbill, Alca torda; Leachs Storm-Petrel, Oceanodroma leucorhoa; Black-legged Kittiwake, Rissa tridactyla; Atlantic Puffin) with good coverage (>100 samples) we did not detect AIV. However, serology indicates infection does occur in Atlantic Puffins, with 22% antibody prevalence found. The possibility of virus spread through dense breeding colonies and the long distance movements of these hosts make a more thorough evaluation of the role for seabirds as hosts of AIV important.

Time Budgets of Common Murres Vary in Relation to Changes in Inshore Capelin Availability

Abstract Changes in capelin (Mallotus villosus) biology since the 1990s have directly or indirectly induced variable breeding conditions for many seabirds in the Northwest Atlantic. Time budgets of the same individual Common Murres (Uria aalge) were examined in relation to annual variations in the arrival of inshore spawning capelin during three consecutive chick-rearing periods (1998–2000) on Great Island in the Witless Bay Ecological Reserve, Newfoundland, Canada. Despite high foraging effort (longer provisioning trips, lower co-attendance time, and faster colony departure after a brooding bout), chick-feeding rates were low during early chick rearing in 2000 due to a mismatch between early egg hatching and the later inshore arrival of spawning capelin. Time budgets of murres breeding on Great Island were examined in relation to those of murres in other nearby colonies and to long-term changes in capelin spawning behavior across decades (1982–1985 versus 1998–2000). Recent overall provisioning rates on Great Island were comparable to those of other nearby colonies during the same time period (with the exception of Funk Island) and to those reported during the 1980s. However, murres breeding in recent years in the reserve exhibited higher foraging effort, which is likely linked to recent changes in the availability of capelin as a result of later spawning, changes in capelin distribution, and their overall smaller size. Murres currently may be constrained to timing their egg laying such that hatching coincides with the arrival of inshore capelin rather than peak capelin abundance and, thus, are vulnerable to sudden changes in the ecosystem.

Development and Validation of a Wing Key to Improve Harvest Management of Alcids in the Northwest Atlantic

Abstract Murres (thick-billed [Uria lomvia] and common [U. aalge]) are legally hunted along the coast of Newfoundland and Labrador, Canada. Razorbills (Alca torda) are also incidentally taken. Only irregular estimates of the total murre harvest are available, so a tool to derive estimates of age- and species-specific harvest is required to effectively monitor the hunt and manage a sustainable harvest. We collected 293 murre and razorbill wings from hunters between 1999–2004, with the goal of identifying wing characteristics that could be used to discriminate age and species. We found that murres and razorbills could be reliably aged (first-yr vs. older) on the basis of molt limits of greater wing coverts. Using a discriminant function (DF) incorporating length of the first primary and second secondary feather, we classified 95–96% of common murres and 99–100% of thick-billed murres correctly to species. First-year thick-billed and common murres also differed in number of pale secondary coverts (median = 12 and 3, respectively), providing another species-specific trait. We developed a key to age and assign species based on these results. We assessed applicability and accuracy of the wing-key with novice observers, who differentiated between murre and razorbill wings using feather-pattern coloration with high accuracy (95 ± 9%) and were able to differentiate between the 2 murres species using 3 techniques: visual assessment of wing shape (83 ± 14% accuracy), the DF (94 ± 6%), and number of worn secondary coverts for first-year birds only (83 ± 5%). Experience increased success rates of aging and species classification using wing shape and number of worn secondary coverts but not using the DF. Despite differences in measurement accuracy and repeatability among observers, the DF proved to be robust. Our results will facilitate implementation of a species composition survey for the murre hunt and will improve identification rates of carcasses found during beached bird surveys in the Northwest Atlantic, aiding in monitoring of alcid populations vulnerable to anthropogenic activities.

Influence of Cyclic Pre-lay Attendance on Synchronous Breeding in Common Murres

Abstract Social stimulation in concert with environmental factors may influence the degree of reproductive synchrony among colonial breeders. Synchronous breeding has been shown to enhance reproductive success by decreasing predation. Although Common Murres (Uria aalge) typically have a cyclic pre-lay attendance pattern, during one of four consecutive breeding seasons we observed one acyclic pre-lay period (1999). The present study investigated how differences in pre-lay attendance patterns may influence breeding synchrony and reproductive success in a Common Murre sub-colony on Great Island, Newfoundland. Compared to the cyclic pre-lay period (2000), the acyclic pre-lay period showed: i) less synchronous egg-laying, ii) pairs spent less time together at their site due to the overall lower attendance by both sexes, but particularly by females, and iii) higher predation during early and first half of peak egg-laying, although overall reproductive success did not differ between years due to high re-laying rates. These results suggest that cyclic attendance during the pre-lay period of Common Murres may influence breeding synchrony within a sub-colony, which may reduce predation during early incubation and late chick rearing.