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The distributions of many marine birds, particularly those that are highly pelagic, remain poorly known outside the breeding period. Here we use geolocator-immersion loggers to study trans-equatorial migration, activity patterns and habitat use of sooty shearwaters Puffinus griseus from Kidney Island, Falkland Islands, during the 2008 and 2009 nonbreeding seasons. Between mid March and mid April, adults commenced a ~3 wk, >15 000 km northward migration. Most birds (72%) staged in the northwest Atlantic from late April to early June in deep, warm and relatively productive waters west of the Mid-Atlantic Ridge (~43−55° N, ~32−43° W) in what we speculate is an important moulting area. Primary feathers grown during the moult had average δ15N and δ13C values of 13.4 ± 1.8‰ and −18.9 ± 0.5‰, respectively. Shearwaters moved into shallow, warm continental shelf waters of the eastern Canadian Grand Bank in mid June and resided there for the northern summer. Migrant Puffinus shearwaters from the southern hemisphere are the primary avian consumers of fish within this ecosystem in summer. During migration birds flew for 78% of the day and 59% of the night, whereas when resident in the northern hemisphere they spent much of their time on the water (70% daylight, 90% darkness). Shearwaters moved south late August to mid September, completing the ~30 000 km figure-of-eight round trip migration in ~2 to 3 wk. The Northern Patagonian Shelf and Argentine Basin were used as a terminal stopover site, where most (79%) shearwaters spent ~1 wk before first returning to the breeding colony for the season. Year-round tracking of seabirds aids the identification of important marine areas and highlights regions where conservation efforts need to be focused.

Fisheries observer data were used to model the distribution of seabird encounters in order to identify potential areas for fisheries closures. Data from the Australian Eastern Tuna and Billfish Fishery (ETBF) in the Tasman Sea were used, and the focal species was the flesh-footed shearwater Puffinus carneipes Gould, 1844 (the species most commonly killed in this fishery). Encounters between flesh-footed shearwaters and longline fishing vessels varied with season, distance from Lord Howe Island, and a number of environmental and oceanographic variables. Encounters were most common south-west of Lord Howe Island, in waters associated with the Tasman Front and the East Australian Current. The resulting model was used to predict overlaps between fisheries and flesh-footed shearwaters during 3 years (1997-98, 2003-04 and 2006-07). During 2003-04, high rates of interaction were predicted in areas with high fishing effort and high observed mortality rates of shearwaters. In 2006-07 most fishing was well to the north of areas with predictions of high interaction rates, and seabird bycatch was low. The shift in fishing locations coincided, and was likely driven by, a change in the fish species targeted by the majority of the fishery. This indicates that the most likely reason for falling bycatch rates in this fishery were movements of the fishing effort away from the birds, rather than changes in fishing technique. These results emphasise the potential of area closures as a method of bycatch mitigation for species that are proving intractable to standard bycatch reduction methods. Our results demonstrate that data collected from fisheries vessels can be used to identify characteristic areas of interactions.

Field-based animal researchers need to balance the potential adverse effects of their research activities against the benefits of research outcomes, but the data required to do this are often lacking. Assessing, and subsequently reporting the effects of researcher activities on wild animal populations can be difficult, so that studies to detect these effects sometimes lack rigour or fail to encompass sufficient time to ensure that the effects are tested under a range of environmental stresses. We monitored the effect of investigators working in colonies of two seabirds, the short-tailed shearwater (Puffinus tenuirostris) and the little penguin (Eudyptula minor). Disturbance of breeding birds while checking nests or the weighing of chicks to monitor growth are very common activities for demographic and ecological studies, but how these activities may influence the birds is rarely measured. We investigated differing levels of disturbance during both activities between 2002-03 and 2008-09 to assess their effect on egg laying, chick survival and growth rate and observed no effect for nest checking or handling of short-tailed shearwaters and indeterminate effects for handling in little penguins. Over a period of several years the study has observed a large-scale decline in the number of breeding shearwaters and includes years when control nests had above and below average breeding success.

The secretive breeding behaviour of petrels makes monitoring their breeding populations challenging. To assess population trends of Cory’s Shearwater Calonectris diomedea, Bulwer’s Petrel Bulweria bulwerii and Macaronesian Shearwater Puffinus baroli in Tenerife from 1990 to 2010, we used data from rescue campaigns that aim to reduce the mortality of fledgling petrels attracted to artificial lights as proxies for trends in breeding population size. Despite increases in human population size and light pollution, the number of rescued fledglings of Cory’s Shearwater and Bulwer’s Petrel increased and remained stable, respectively, whereas numbers of rescued Macaronesian Shearwaters sharply declined. In the absence of more accurate population estimates, these results suggest a worrying decline in the Macaronesian Shearwater’s breeding population.

Small black-and-white shearwaters of the genus Puffinus are distributed globally, and their phylogenetic relationships are complex and uncertain. In 1963 a small shearwater collected at Midway Atoll in the North Pacific Ocean was identified as a Little Shearwater (P. assimilis), but several physical features suggest closer alliance with Audubon's Shearwater (P. lherminieri) and its relatives. Biometrics indicate that the taxon this specimen represents is smaller than any other known shearwater, and phylogenetic analyses indicate it is distinct, with a pair-wise sequence divergence of at least 3.8% from related taxa. We thus propose a new species based on the specimen: Bryan's Shearwater (Puffinus bryani nom. nov.). The breeding and nonbreeding ranges of Bryan's Shearwater are unknown, but a physical resemblance to the North Atlantic boydi (of controversial taxonomic status within Puffinus) suggests an affiliation with subtropical or tropical waters. Bryan's Shearwater is apparently rare and coul...

Procellariiform seabirds accumulate large amounts of lipid during the nestling period. Chick obesity functions as a buffer against irregular attentiveness by parents delivering meals. Surprisingly the assimilation mechanism necessary to attain obesity remains unclear. This study presents the first measurements of assimilation efficiency in relation to age and diet throughout the long nestling period of a Procellariidae. To determine the assimilation efficiency and diet effects on growth, Shorttailed Shearwater Puffinus tenuirostris chicks were fed in captivity on different diets of marine organisms (krill Euphausia superba, squid Nototodarus sloani and fish Hyperlophus vittatus) from age 10 to 85 days. Assimilation efficiency was highest (mean 93.7%) among young chicks (10–29 days old) then declined, becoming stable (mean 80.9%) among older (70–85 days old) pre-fledging chicks. It was noted that the krill-fed chicks showed consistently higher assimilation efficiencies, not only when young (mean 9...

11 pages, 6 figures, 5 tables, While breeding, seabirds are limited to exploiting resources within a restricted area around their breeding site and should exploit the closest productive marine areas within their distribution range. We investigated this hypothesis in one of the most endangered European seabirds, the Balearic shearwater Puffinus mauretanicus (ca. 3200 breeding pairs), restricted to the Balearic Islands. Our aims were (1) to assess whether isotopic evidence (i.e. stable isotopes of δ13C and δ15N) of foraging habitat partitioning occurs among northern, central and southern populations, (2) to geographically locate population-specific potential foraging grounds along the Iberian continental shelf, and (3) to assess whether oceanographic conditions could explain observed patterns of stable isotopes (SI). SI values showed a latitudinal gradient, with birds from the northern population having lower δ15N and δ13C values than central and southern populations. Potential foraging grounds of northern, central and southern populations were centred in Cape Creus, Ebro Delta and Cape La Nao, respectively, results which were supported by habitat models. Oceanographic conditions in each potential foraging ground were different; the northern population used richer, colder and deeper waters compared to the central and southern populations. Chlorophyll a was the main oceanographic variable that explained variation in SI values. We hypothesised that SI differences among Balearic shearwater populations might be a consequence of differences in baseline isotopic values among potential foraging grounds rather than real differences in diet. Our comprehensive study also provides important information for management strategies to conserve this critically endangered shearwater, This study was funded by Govern de les Illes Balears, DISCBIRD (QLRT-2000-00839) and LIFE projects (European Commission) and the Spanish Ministries of Education and Science (ref. BOS2003-01960 and REN2002-00450) and of the Environment (ref. 024A/2002). M.L. was supported by fellowships from Govern de les Illes Balears and Institut Menorquí d’Estudis, as well as by a postdoctoral contract of the Spanish Ministry of Education and Science (ref. EX-2007-1148) and Marie Curie Individual Fellowship (PIEF-GA-2008-220063). J.N. was supported by a researcher contract from of the Spanish Ministry of Science and Innovation (Juan de la Cierva program). M.G.F. and M.G. by Ramon y Cajal and I3P contracts, respectively, of the Spanish Ministry of Education and Science

Bottom trawl fishing provides substantial amounts of normally unavailable demersal prey to seabirds (e.g., discards), affecting their life-history traits and population dynamics, as well as community structure. Within this framework, we studied seabird-trawling interactions throughout the annual cycle in a poorly studied ecosystem in the Mediterranean, the Balearic archipelago, on a both species-specific and a community level. Whereas the species-specific approach showed a significant influence of season (phenology) on shaping seabird’s trawling attendance patterns, the spatio-temporal coupling of regional community was a result of a complex interaction between fisheryrelated variables. The most frequent and abundant species were the yellow-legged gull Larus michahellis and Cory’s shearwater Calonectris diomedea, the latter attending vessels in higher numbers than expected from local population figures. Conversely, the remaining breeding species occurred in lower numbers than expected according to their local breeding populations, suggesting that discards were of relatively little importance. Discarding activity took place over the entire shelf and continental slope surrounding Mallorca, but especially in the southwest, adjacent to the breeding grounds of approximately 12% of the Balearic total seabird breeding population, including 13% the Balearic shearwater Puffinus mauretanicus world population. Overall discards corresponded to 0.74 of landings (range: 0.09‐ 6.00) and consisted primarily of fish followed by crustaceans and molluscs (approximately 80, 15, and 5%, respectively). Seabird-trawling interactions should be taken into account in the frame of an ecosystem-based approach to fisheries management, and particular attention should be devoted to the critically endangered Balearic shearwater.

Research procedures can have a detrimental effect on the reproductive success of the study species. In this study, the frequency of investigator disturbance on Short-tailed Shearwaters Puffinus tenuirostris was examined experimentally throughout the incubation period to assess whether disturbance influences hatching success, pre-fledging chick survival and chick body size. Handling of incubating birds every day, every 3 days and once a week reduced hatching success by 100, 61 and 39%, respectively, compared with pairs that were not disturbed. Most failures resulted from egg abandonment by the parents, particularly during the early stage of incubation. Chick survival did not differ between treatment groups, but control chicks were significantly heavier and had larger bill depths and longer wings. The difference in chick body mass and size observed between the control and disturbed chicks might be due to physiological or behavioural mechanisms in adults or carry-over effects from the incubation stage to the next life-history stage. Reduced offspring quality has the potential to affect post-fledging survival and recruitment. These findings are significant in broader terms because any investigator disturbance that reduces reproductive success, survival and offspring fitness could interfere with the accurate assessment of demographic parameters and exacerbate population declines.

The distribution of wintering seabirds is influenced by biotic and abiotic oceanic processes. Ocean productivity is a main parameter at small and large scales, but the role of abiotic parameters at large scales may be explored indeed. Thus, we conduced bird counting between Rio grande and Rio de Janeiro (Brazil) onboard NApOc Ary Rongel from 11 until 13 april, 2009. The samples comprised 10 minutes each hour, from sunrise until sunset. Abiotic data were collected by NApOc Ary Rongel equipments. Data were analysed through CDA, PCA of species and CDA functions, and Multiple Regressions of CDA functions with sum of all Antarctic and Subantarctic abundances, and sum of all tropical and subtropical abundances. We verified Through PCA Thalassarche chlororhynchos and T. chrysostoma are associated with greater wind speed and air temperature, Calonectris diomedea and Puffinus gravis are associated with greater depths, sea temperature and atmospheric pressure. As a group, Antarctic / Subantarctic species are associated with higher wind speed, higher air temperature, lower atmospheric pressures and lower depths. Tropical / subtropical birds did not responded to any CDA functions. At small scales, seabirds tend to respond to gradients of productivity, chlorophyll concentrations, depth and salinity. Nonetheless at larger scales, Seabirds may be mainly driven by wind, associated with low pressures zones. At larger scales, the ability of disperse over greater distances may play a fundamental role.

Seabirds and large fishes are important top predators in marine ecosystems, but few studies have explored the potential for competition between these groups. This study investigates the relationship between an observed biennial change of pink salmon ( Oncorhynchus gorbuscha ) biomass in the central Bering Sea (23 times greater in odd-numbered than in even-numbered years) and the body condition and diet of the short-tailed shearwater ( Puffinus tenuirostris ) that spends the post-breeding season there. Samples were collected with research gill nets over seven summers. Both species feed on krill, small fishes and squid. Although the mean pink salmon catch per unit effort (in mass) over the study region was not related significantly with shearwater's stomach content mass or prey composition, the pink salmon biomass showed a negative and significant relationship with the shearwater's body mass and liver mass (proxies of energy reserve). We interpret these results as evidence that fishes can negatively affect mean prey intake of seabirds if they feed on a shared prey in the pelagic ecosystem.

Incidental capture of seabirds is a conservation concern because such periodic ‘bycatch’ may cause population declines. Not all birds die upon capture, but distinctions between total and dead captures are rarely done. Thus, it is currently unclear whether using total captures is an adequate simplification, for example when studying factors associated with bycatch. We investigated this question by analysing total and dead procellariiform seabird captures of 663 trawling operations between 1996 and 2008 in the Exclusive Economic Zone of New Zealand. As potential factors associated with bycatch, we considered eleven technical and seven environmental characteristics recorded by onboard observers during commercial trawling. A total of 1 231 procellariids were recovered as bycatch, with sooty shearwaters (Puffinus griseus) comprising 98% of the bycatch sample. Our analyses indicated that specific technical (headline height) and environmental factors (month, daylight, sea state, area code) influenced both total and dead captures of sooty shearwaters, with similar results for both response variables. Using total captures may thus be an adequate simplification in the interpretation of sooty shearwater captures in New Zealand trawl fisheries, and practices that mitigate the overall capture of birds will be most effective.

Ground baiting was carried out in an operational pest control program between 1993 and 1995 aimed at eradicating Black rats Rattus rattus from Bowen Island in Jervis Bay. Rattus rattus was abundant across most of the Island and given their propensity to prey on ground nesting sea birds, were identified as a threat to Shearwaters (Puffinus spp.) in the Bowen Island Management Plan 1988. Small mammal trapping and spotlighting surveys were carried out prior to baiting in 1993 to assess the non-target species at risk of poisoning. No native mammal species were captured, although 97 R. rattus were trapped over 353 trap nights and two were spotlighted on two survey nights. Twenty three baiting transects spaced 50 metres apart in dense vegetation were hand cut across the Island and bait stations (n=228) were placed every 50 metres along each transect. An additional 50 bait stations were placed on rock platforms for the last two of twelve baiting events. Two rodenticides were used to avoid bait shyness (Brodificoum and Bromadiolone). Chew sticks were deployed on two occasions, in 1996 and 2002, to detect R. rattus presence and no sign of R. rattus were recorded. In 2004, trapping and spotlighting surveys were carried out to determine the success of the control program and determine if native species had responded to R. rattus control. There was still no sign of native ground dwelling mammals. The lack of gnawing on the chew sticks supported our conclusion that R. rattus have been eradicated from Bowen Island.

A survey of the at-sea distributions of 1) planktivorous Short-tailed Shearwater Puffinus tenuirostris, migrating to their northern summering area and 2) piscivorous Rhinoceros Auklet Cerorhinca monocerata, breeding in the northern Sea of Japan off Hokkaido, was carried out by ship, from 16 to 28 May 2008. Avian censuses were combined with: acoustic surveys aimed at measuring prey density, and sea surface temperature (SST) surveys. Surface Chlorophyll a distribution was obtained using satellite imagery. The density of shearwaters was correlated positively with 200 kHz SA (the index of density of zooplankton including krill) at the 10 km scale, and 200 kHz SA was correlated negatively both with SST and Chlorophyll a. However, shearwater densities were not correlated significantly with SST and Chlorophyll a. The result suggest that migrating shearwaters may be able to find patches of krill in cold water. In contrast, the density of Rhinoceros Auklets was not correlated with 38 kHz SA (the index of pelagic fish density) or 200 kHz SA at any scale.

A fossil skull of Puffinus sp. (Aves: Procellariidae), 85 mm long, is reported from the mid-Pliocene Taihape Mudstone (3.220–3.110 Ma; Waipipian Stage) at Mataroa, near Taihape, central North Island, New Zealand. This is the first described evidence for Puffinus in New Zealand's pre-Pleistocene fossil record. The skull belonged to a shearwater of a species close in skull size and proportions to the present-day wedge-tailed shearwater (P. pacificus). It could be conspecific with P. pacificus, or of the ancestral species from which P. pacificus evolved. Certainty on that point is difficult with a sample of one and less than perfect preservation and exposure, however. The Mataroa fossil, and undescribed fossil evidence from Hawera, Taranaki, establish the presence of a shearwater fauna of at least several species in Pliocene coastal waters off the North Island of New Zealand. This is unsurprising given the importance of procellariiforms in New Zealand's current avifauna.

During nesting periods, seabirds are known to exhibit considerable inter-annual vari- ability in diets, yet little is known about the diets of pelagic seabirds during non-breeding periods. Over 5 yr (2005 to 2009), we studied dietary partitioning between sympatric greater and sooty shear- waters, Puffinus gravis and P. griseus, during migratory staging periods in the Northwest Atlantic. Stable-isotope (SI; n = 253) and fatty-acid (FA; n = 127) signatures from blood samples were used to assess inter-annual patterns in diet and quantify prey choices. In addition to significant effects of year, capture site, and body condition, SI signatures revealed subtle, but consistent, dietary partition- ing between species. In all years, greater shearwaters fed at slightly higher trophic levels (overall mean δ 15 N = 13.6‰) and lower δ 13 C (-19.1‰) than sooty shearwaters (δ 15 N = 13.3‰, δ 13 C = -18.9‰). SI mixing models revealed that sooty shearwaters relied more heavily on euphausiids Meganyc- tiphanes norvegica, while greater shearwaters consumed more herring Clupea harengus, squid Illex illecebrosus, and, in some years, mackerel Scomber scombrus. In 2005/2006, bird diets consisted pri- marily of herring and krill, but demonstrated a shift towards krill and squid during 2007-2009. FA from bird plasma showed little inter-specific partitioning but a strong signal of annual variation for both species. We used a subset of prey FA and a modified multivariate approach to model bird diets and obtained dietary preferences broadly in agreement with SI results. The present study revealed inter-annual variability and dietary partitioning in sympatric species of pelagic seabirds, and high- lights potential shifts in prey availability to predators in the Bay of Fundy.

Tristan Thrushes or Starchies Nesocichla eremita are known to feed on seabird eggs. We show they are able to open the eggs of birds as large as small albatrosses. Starchies were involved in almost half of all egg losses by Great Shearwaters Puffinus gravis during the early incubation period in a small study colony at Inaccessible Island, South Atlantic Ocean. They also enter burrows to remove and kill petrel chicks up to at least 70 g. Starchies are thus potentially significant predators of seabird eggs and chicks, and may select against egg neglect and early cessation of brooding by burrowing petrels at the Tristan islands. Starchies previously were recorded killing adult White-bellied Storm Petrels Fregetta grallaria at Inaccessible Island. This behaviour now includes White-faced Storm Petrels Pelagodroma marina. It is likely that the Starchies hunt adult storm petrels directly, taking them from their burrows.

Estimating the population of burrow-nesting seabirds is a challenging task, as human presence in the colony creates disturbances and can damage burrows and occupants. Here, we present a novel method using aerial photographs taken with Unmanned Aerial Vehicles (UAVs) to estimate the population size of a burrow-nesting seabird, the Black-vented Shearwater (Puffinus opisthomelas), on Natividad Island, Mexico. Our results provide a census of burrows in the colony, with very low detection error (5.6%). This is greater accuracy compared to other methods based on extrapolating results from sample plots to total colony area. We then combined this burrow census with ground truth data on occupancy to estimate population size. We obtained a population estimate of 37,858 and 46,322 breeding pairs for 2016 and 2017 respectively. The proposed method provides a cost effective and repeatable approach for monitoring numbers of burrows occupied in a colony, thereby enabling easier and faster estimates of population trends. We suggest this method can be valid for other burrow-nesting species in habitats without dense vegetation cover.

Identifying the primary foraging grounds of abundant top predators is of importance in marine management to identify areas of high biological significance, and to assess the extent of competition with fisheries. We studied the search effort and habitat selection of the highly abundant short-tailed shearwater Puffinus tenuirostris to assess the search strategies employed by this wide-ranging seabird. During the chick-rearing period 52 indi- viduals were tracked performing 39 short foraging trips (1-2 days), and 13 long trips (11-32 days). First-passage time analysis revealed that 46% of birds performing short trips employed area-restricted searches, concentrating search effort at an average scale of 14 5 km. Foraging searches were more continuous for the other 54%, who travelled faster to cover greater distances, with little evidence of area-restricted searches. The prey returned indicated that continuous searchers consumed similar prey mass, but greater prey diversity than area-restricted search birds.On long trips 23% of birds travelled 500-1000 km to neritic (continental shelf) habitats,showing weak evidence of preference for areas of higher chlorophyll a concentration, and foraged at a similar spatial scale to short trips. The other 76% performed rapid outbound flights of 1000-3600 km across oceanic habitats commuting to regions with higher chlorophyll a. The spatial scale of search effort in oceanic habitat varied widely with some performing broad-scale searches (260-560 km) followed by finer-scale nested searches (16-170 km). This study demonstrates that a range of search strategies are employed when exploiting prey across ocean basins.The trade-offs between different search strategies are discussed to identify the value of these contrasting behaviours to wide-ranging seabirds.

Ecosystem engineers such as burrowing seabirds can increase habitat availability for sympatric taxa – but only if the burrow's owner allows other species to use the newly created shelter site. Our studies on a small Pacific island suggest that an avian burrower (the wedge-tailed shearwater Puffinus pacificus) is both a facilitator and a competitor for amphibious seasnakes. Video camera inspection of 102 burrows revealed frequent usage of these burrows as retreat sites by the snakes, with Laticauda laticaudata restricted to burrows

Cultural evidence suggests that sooty shearwater (Puffinus griseus) chicks have been harvested by Rakiura Māori on islands in southern New Zealand since prehistoric times. Concerns exist that modern harvests may be impacting sooty shearwater abundance. We modeled human-related and ecological determinants of harvest (total no. of individuals harvested) of sooty shearwater chicks on 11 islands and examined the relationship between shearwater abundance and harvesting rates (chicks/hr) and harvester behavior throughout the harvesting season. Models best explaining variation in harvest between harvesting areas (manu), for both the early and late parts of the harvesting season, included harvester-days (included in all models with change in deviance information criteria [ΔDIC], ΔDIC < 8.36 and ΔDIC < 11.5, for the early and late periods, respectively). Other harvest determinants included shearwater density, size of the manu, and number of people helping harvesters (all included in the top 5 models withi...

Capsule When moonlight levels are low, shearwaters and storm‐petrels are attracted to artificial lighting at night at St Kilda and may be killed, but impacts are lessened by deliberate light reduction measures. Aims To determine the scale and impacts of attraction of petrels to artificial lights at St Kilda, investigate influences of the lunar cycle, and assess effects of reducing artificial light emissions. Methods Nightly numbers of Manx Shearwaters Puffinus puffinus, Leach's Storm‐petrels Oceanodroma leucorhoa and European Storm‐petrels Hydrobates pelagicus attracted by artificial lights were recorded in September and October from 2005 to 2008. Effects of experimental reductions to light emissions in 2007 and 2008 were assessed, together with variation in annual moonlight, mortality rates, and age of birds found. Results Reductions to light emissions caused a decrease in numbers of Leach's Storm‐petrels attracted, but had less effect on attraction of Manx Shearwaters. Only juveniles were found, the maj...

The ability of Manx shearwaters (Puffinus puffinus) to locate their nesting burrows at night was investigated using observation and experiments. Shearwaters walking to their burrows did so at random with respect to the wind direction, and did not vocalize, suggesting that visual cues are important to successful burrow homing. Experiments to test whether vision, audition or olfaction functioned in guiding birds back to burrows supported this conclusion.

1. Seabirds killed incidentally in Australia's eastern tuna and billfish (ETBF) longline fishery between September 2001 and June 2006 were examined to evaluate species composition and to relate, where possible, capture events to operational and environmental factors. 2. During this period 2.129 million hooks on 2202 shots were observed, and 369 birds were reported killed. The majority (78%) of these were flesh-footed shearwaters ( Puffinus carniepes ), 53% of which were male and 44% female. Smaller numbers of medium to large sized albatrosses ( Diomedeidae , predominantly female) and other shearwaters ( Puffinus spp.) and petrels ( Pterodroma spp.) dominated the remainder of the bycatch. 3. Of the 369 birds reported taken as bycatch, 280 were available for necropsy, and species identifications performed in situ by observers were assessed. While observer identifications were generally correct for common species, performance was poor for less common ones. 4. The geographical location (latitude) of shots, season, time of day at which shots were set, and bait type and life status (dead or alive) influenced the seabird bycatch rate. The majority of captures (87% overall) occurred between 30 and 35°S, with bycatch being lowest in winter, and remaining at similar levels across the other seasons. 5. The use of live fish bait was generally associated with increased captures of both seabirds overall, and flesh-footed shearwaters in particular.

The extinct species Puffinus parvus Shufeldt of Bermuda is shown to be synonymous with the living taxon Puffinus boydi of the Cape Verde islands. This species occurred on Bermuda throughout the last 400 000 years, during both glacial and interglacial intervals, and into the Holocene up until the arrival of humans when introduced predators evidently caused its extirpation. Subsequently, the island was colonized briefly by the Caribbean species Puffinus lherminieri, which in turn was extirpated from the island in the 20th Century. The indications are that P. boydi successfully outcompeted P. lherminieri on Bermuda until it was removed through human agency, thus closely paralleling the situation documented for two species of Megadyptes penguins in New Zealand. Thus P. lherminieri and P. boydi have long functioned as biological species and should be considered as full species along with the cold-water species Puffinus baroli of the North Atlantic. Restoration efforts for small shearwaters on Bermuda should now focus on P. boydi rather than P. lherminieri. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 699–707.

We analysed mercury levels in the breast feathers of several breeding seabirds – White-tailed Tropicbird (Phaethon lepturus), Audubon’s Shearwater (Puffinus lherminieri), Lesser Noddy (Anous tenuirostris), White Tern (Gygis alba), Sooty Tern (Onychoprion fuscata) and Roseate Tern (Sterna dougallii) – on Aride Island in the Seychelles during three periods between 1996 and 2005. Mercury concentrations tended to be higher in the second sampling period (2002–03) than the first (1996–97), particularly for inshore-feeding species. El Nino events in 1997–99 and 2002–03 might help to explain this pattern, through an increase in mercury bioavailability for seabirds that forage inshore. However, levels of mercury in tissue decreased significantly from the first period (1996–97) to the third period (2004–05) for inshore-foraging species (Lesser Noddy mean ± s.e.: 0.82 ± 0.02 μg g–1 v. 0.53 ± 0.06 μg g–1 respectively) and more wide-ranging, offshore-feeding species (Sooty Tern: 1.16 ± 0.05 v. 0.59 ± 0.04; White-tailed Tropicbird: 1.82 ± 0.05 v. 1.43 ± 0.09). Wide-ranging species of seabirds are more likely to be useful bioindicators at large spatial scales, with such species suggesting a decreasing trend in mercury pollution in the western Indian Ocean.

To characterize the environmental factors affecting seabird population trends in the central portion of the California current system (CCS), we analyzed standardized vessel-based surveys collected during the late spring (May–June) upwelling season over 22 yr (1985–2006). We tested the working hypothesis that population trends are related to species-specific foraging ecology, and predicted that temporal variation in population size should be most extreme in diving species with higher energy expenditure during foraging. We related variation in individual species abundance (number km � 2 ) to seasonally lagged (late winter, early spring, late spring) and concurrent ocean conditions, and to long-term trends (using a proxy variable: year) during a multi-decadal period of major fluctuations in the El Nino-Southern oscillation (ENSO) and the Pacific decadal oscillation (PDO). We considered both remote (Multivariate ENSO Index, PDO) and local (coastal upwelling indices and sea-surface temperature) environmental variables as proxies for ocean productivity and prey availability. We also related seabird trends to those of potentially major trophic competitors, humpback (Megaptera novaeangliae) and blue (Balaenoptera musculus) whales, which increased in number 4–5-fold midway during our study. Cyclical oscillations in seabird abundance were apparent in the black-footed albatross (Phoebastria nigripes), and decreasing trends were documented for ashy storm-petrel (Oceanodroma homochroa), pigeon guillemot (Cepphus columbus), rhinoceros auklet (Cerorhinca monocerata), Cassin’s auklet (Ptychoramphus aleuticus), and western gull (Larus occidentalis); the sooty shearwater (Puffinus griseus), exhibited a marked decline before signs of recovery at the end of the study period. The abundance of nine other focal species varied with ocean conditions, but without decadal or long-term trends. Six of these species have the largest global populations in the CCS, and four are highly energetic, diving foragers. Furthermore, three of the diving species trends were negatively correlated with the abundance of humpback whales in the study area, a direct competitor for the same prey. Therefore, on the basis of literature reviewed, we hypothesize that the seabirds were affected by the decreasing carrying capacity of the CCS, over-exploitation of some prey stocks and interference competition from the previously exploited, but now increasing, baleen whale populations. Overall, our study highlights the complexity of the ecological factors driving seabird population trends in the highly variable and rapidly changing CCS ecosystem.

Summary 1. Several alternative explanations have been proposed to account for the evolution of nestling obesity in a variety of avian groups. These predict quite different patterns of fat storage, utilization and food solicitation by chicks of different ages, yet surprisingly few studies have measured changes in begging behaviour or use of fat stores during chick development. 2. We tested the applicability of these hypotheses for Manx shearwaters Puffinus puffinus, by direct measurement of changes in plasma lipid metabolites (non-esterified fatty acids and β-hydroxybutyrate) and begging behaviour throughout the chick’s development until fledging. 3. Chicks metabolized fat reserves during periods of parental absence throughout their development but there was no evidence that even the poorest fed chicks were close to exhausting these reserves during the period of mass growth. Chicks begged more vigorously during the period of mass loss at the end of the nestling period than at any previous stage of their development, and mobilization of fat stores was also at a maximum during this period in well-fed chicks, coinciding with a decrease in food provisioning by parents. Increases in lipid metabolite levels occurred at an earlier age in poorly-fed chicks than in well-fed chicks and were followed by a marked decline only in poorly-fed chicks, indicating that they were exhausting their fat stores. 4. These findings are incompatible with several of the proposed explanations for nestling obesity and mainly support the hypothesis that fat stores fuel chicks through a period of several weeks of reduced food provisioning prior to fledging, when parents are unable or unwilling to maintain earlier levels of food provisioning, despite increased solicitation from chicks.

Pelagic seabirds obtain food from oceans where the availability of their prey changes rapidly both seasonally and spatially. Here, we investigated changes in the trophic habits of the critically endangered Balearic shearwater (Puffinus mauretanicus) through the breeding season and tested for dietary differences between sexes and age classes. We analysed δ15N and δ13C values in blood of adults during the pre-incubation, incubation and chick-rearing periods and of their chicks. Using a two-isotope mixing model, we estimated dietary contributions based on isotope values from potential prey species which included small pelagic species available naturally and demersal fish species available only from trawling discards. Balearic shearwaters showed clear isotopic and dietary variation through the breeding season. During pre-incubation, breeding adults appeared to exploit demersal fish, whereas during the incubation and chick-rearing period, they fed mainly on pelagic anchovies (Engraulis encrasicolus) and pilchards (Sardina pilchardus). Similarly, chicks were fed mainly with anchovies, a resource with a high energetic value. This variation in the dietary habits of adult shearwaters during the breeding season was probably related to both natural and fishery-induced seasonal changes in the availability of potential prey species within their main feeding grounds. However, changes in the nutritional requirements of the shearwaters could also play an important role. Indeed, diet differed between sexes during pre-incubation: females fed less on trawling discards and more on small pelagic fish than males. This sexual segregation in diet could be the consequence of higher nutritional requirements of females during this period. Our study reveals the differential importance of both trawling discards and small pelagic fish species for a pelagic seabird depending on the breeding period and illustrates the importance of considering the entire breeding season when making inferences about the importance of specific prey in seabird dietary studies. © Springer-Verlag 2009.

Although seabird population biology is relatively well studied, little data exists on mor- tality at-sea. Beached bird surveys are used to identify patterns of seabird mortality, but resulting pat- terns are difficult to interpret without corresponding data on at-sea density. We examined seabird mortality relative to at-sea density in Monterey Bay, California over 10 yr by integrating data from monthly beachcast seabird and offshore seabird censuses. Beachcast seabird numbers were rela- tively constant (mean 2.82 ± 0.31 seabirds km -1 ) throughout the year. At-sea seabird density (mean 148.9 ± 16.12 seabirds km -2 ) peaked in the summer upwelling period and was least in the winter Davidson period. A principal components analysis of seasonal climatic, prey availability, and anthro- pogenic variables for Monterey Bay derived 3 significant principal components (PCs) (explaining 70% of variance) characterized by storm activity and low prey availability (PC1), river discharge and krill abundance (PC2), and oiling (PC3). These principal components were used in detailed analyses of the 2 most abundant seabird species and indicate that sooty shearwater Puffinus griseus relative mortality is greatest during decreased productivity and increased storm activity. While relative mor- tality of common murres Uria aalge cannot be explained by the derived principal components, rela- tive mortality increased in late winter when prey availability decreased concurrent with the annual increase in reproductive stress. Beachcast seabird data is difficult to interpret in isolation; however, when linked to at-sea densities of seabirds, it becomes a powerful tool to examine the relative impacts of oceanography and direct human perturbations on seabird demography.

Breeding sooty shearwaters Puffinus griseus cycle between long (11 to 14 d) and short (1 to 2 d) foraging bouts at sea, but no information exists on bird behavior during these trips. We tested the hypothesis that shearwaters use these long trips to travel to distant Antarctic waters com- pared to remaining in local waters. Patterns of habitat use of 28 breeding sooty shearwaters were studied using 6 g archival data loggers that recorded location, environmental temperature, and div- ing behavior. Dive activity was compared to remotely-sensed environmental data to characterize the habitats visited by shearwaters on long and short trips. Sooty shearwaters traveled predominantly (70% of all long trips) to cold oceanic waters along the Polar Front (mean ± SD, 1970 ± 930 km from colony) on long trips or remained within warmer neritic waters of the New Zealand shelf (515 ± 248 km from colony) on short trips. Diving depths (mean depth 15.9 ± 10.8 m, max depth 69.9 m, n = 2007 dives) were not significantly different between excursion types. Activity patterns suggest that shearwaters commuted between distant foraging grounds (e.g. Polar Front) and the breeding colony and that more than 95% of diving activity occurred during daylight hours. Although shearwaters traveled primarily to Antarctic waters on long trips, occasional trips around New Zealand waters were observed; all but 2 birds were from the northern-most study colony. Oceanic habitats in Antarc- tic waters were substantially different from neritic habitats around New Zealand, indicating that shearwaters experience dramatically different environmental conditions associated with each excur- sion type. The ability of sooty shearwaters to use 2 vastly different habitats provides greater flexibil- ity for maximizing resource acquisition during breeding and reduces competition near the colony. Contribution to the Theme Section 'Spatiotemporal dynamics of seabirds in the marine environment' OPENEN

We investigated variations in the small- to meso-scale abundance and distribution of the 6 most abundant seabird species in the northern California Current — black-footed albatross Phoe- bastria nigripes, sooty shearwater Puffinus griseus, pink-footed shearwater Puffinus creatopus, fork- tailed storm-petrel Oceanodroma furcata, common murre Uria aalge, and Cassin's auklet Ptycho- ramphus aleuticus — during the upwelling season of 2000 and 2002. Covariates (21 total), with importance assessed using logistic and generalized linear modeling and an information theoretic approach, included physical features such as sea surface temperature, dynamic height (apparent water-column pressure), and pycnocline depth; biological factors such as chlorophyll maximum; and food-web factors such as the density of 3 size classes of zooplankton, the density of potential piscine competitors, i.e. Pacific salmon Oncorhynchus spp., and abundance of fish prey such as zooplankton, northern anchovy Engraulis mordax, and the juveniles of salmon and demersal fishes. The most important factors explaining seabird occurrence changed from mesoscale physical features during a food-rich year (2002; exhibited over 15 to 30 km) to smaller-scale occurrence of actual prey patches during a food-poor year (2000

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:42:51Z No. of bitstreams: 1 S1676-06032009000300004.pdf: 336166 bytes, checksum: 494bad2e5b3c6a977bdeaf682399badf (MD5) Made available in DSpace on 2013-08-22T18:42:51Z (GMT). No. of bitstreams: 1 S1676-06032009000300004.pdf: 336166 bytes, checksum: 494bad2e5b3c6a977bdeaf682399badf (MD5) Previous issue date: 2009-09-01 Made available in DSpace on 2013-09-30T19:30:30Z (GMT). No. of bitstreams: 2 S1676-06032009000300004.pdf: 336166 bytes, checksum: 494bad2e5b3c6a977bdeaf682399badf (MD5) S1676-06032009000300004.pdf.txt: 28674 bytes, checksum: 03d5a4804db9746836ffdc9812c9a104 (MD5) Previous issue date: 2009-09-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:12:19Z No. of bitstreams: 2 S1676-06032009000300004.pdf: 336166 bytes, checksum: 494bad2e5b3c6a977bdeaf682399badf (MD5) S1676-06032009000300004.pdf.txt: 28674 bytes, checksum: 03d5a4804db9746836ffdc9812c9a104 (MD5) Made available in DSpace on 2014-05-20T13:12:19Z (GMT). No. of bitstreams: 2 S1676-06032009000300004.pdf: 336166 bytes, checksum: 494bad2e5b3c6a977bdeaf682399badf (MD5) S1676-06032009000300004.pdf.txt: 28674 bytes, checksum: 03d5a4804db9746836ffdc9812c9a104 (MD5) Previous issue date: 2009-09-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Estômagos de 222 tubarões-azuis coletados ao longo da costa brasileira foram analisados, sendo 116 da região nordeste e 106 da região sul. Um total de 51 táxons de presas foram identificados. Os itens mais importantes na região sul foram baleias Mysticeti, teleósteos, o peixe gempilídeo Ruvettus pretiosus e o nomeídeo Arioma bondi. Cefalópodes foram mais diversos, com preferência pelas espécies migradoras verticais Histioteuthis spp., Cranchiidae e o polvo epipelágico Ocythoe tuberculata. Na região nordeste, o tubarão-azul consumiu principalmente teleósteos, incluindo o peixe alepisaurídeo Alepisaurus ferox e o gempilídeo Gempylus serpens. Entre os cefalópodes, Histioteuthis spp. e o polvo epipelágico Tremoctopus violaceus foram os itens principais. Predação sobre cardumes foi ocasional, como observada para Arioma bondi. Aves também foram consumidas em ambas as regiões. Puffinus gravis foi o quinto item mais freqüente na região nordeste. Durante o ciclo migratório reprodutivo, o tubarão-azul costuma predar nas adjacências da termoclina, que é mais profunda na região nordeste e mais perto da superfície na região sul. Stomachs from 222 blue sharks collected along the Brazilian coast were analyzed - 116 from the northeastern region and 106 from the southern region. A total of 51 prey taxa were identified. The most important prey items in the southern region were Mysticeti whales, teleosteans, the gempylid Ruvettus pretiosus and the nomeid Arioma bondi. Cephalopods were more diverse, with dominance of vertical migrants Histioteuthis spp., Cranchiidae and the epipelagic octopus Ocythoe tuberculata. In the northeastern region, blue sharks consumed mainly teleosteans, including the alepisaurid Alepisaurus ferox and the gempylid Gempylus serpens. Among cephalopods, Histioteuthis spp. and the epipelagic octopus Tremoctopus violaceus were the dominant items. Predation upon schooling prey was occasional, as observed on Arioma bondi. Birds also were consumed in both regions; Puffinus gravis was the fifth most frequent item in the northeastern region. During the reproductive migration cycle, blue sharks likely prey in the thermocline, which is deeper in the northeastern region and closer to the surface in the southern region. Universidade Estadual Paulista Departamento de Biologia Marinha Universidade Federal Rural de Pernambuco (UFRPE) Departamento de Pesca Universidade Estadual Paulista Departamento de Biologia Marinha

Although most Manx shearwaters (Puffinus puffinus) in the UK are protected within Special Protection Areas (SPAs) at their breeding colonies, such site-based protection does not currently extend into the marine environment. Manx shearwaters form rafts (dense flocks of birds) on the sea adjacent to their breeding colony from late afternoon onwards, before coming ashore after nightfall. The ecological and protection requirements of Manx shearwaters in the UK would be more completely addressed if existing SPA boundaries were extended into adjacent marine areas to include those used for rafting behaviour. However the spatial extent of rafts has never been assessed accurately. Because rafting behaviour continues after nightfall, radio-telemetry was used to investigate rafting distributions of Manx shearwaters around the three largest UK colonies: Skomer (south-west Wales), Bardsey (north-west Wales) and Rum (north-west Scotland). Totals of 30, 28 and 30 birds were radio-tagged, with 174, 264 and 385 rafting locations estimated for Skomer, Rum and Bardsey, respectively. Kernel contour analysis was used to describe the ‘rafting range’ around each colony. The maximum extent of the 95% kernel contours was used to determine the area which would encompass most rafting birds. The maximum extents of rafting ranges were 4, 6 and 9 km, respectively for Skomer, Rum and Bardsey. We believe this is the first successful illustration of how radio-telemetry data can potentially be used to define protected areas for birds in the marine environment.

The extent and intensity of artificial night lighting has increased with urban development worldwide. The resulting light pollution is responsible for mortality among many Procellariiformes species which show nocturnal activity on their breeding grounds. Here, we report light-induced mortality of Procellariiformes during a 9-year study (1998‐2006) on Tenerife, the largest island of the Canary archipelago. A total of 9880 birds from nine species were found grounded, the majority being Cory’s Shearwaters Calonectris diomedea (93.4%). For this species the majority of grounded birds were fledglings (96.4%), which fall apparently while leaving their nesting colony for the first time; for the smaller species (storm-petrels) adult birds were more often grounded than fledglings. For almost all species, grounding showed a seasonal pattern linked with their breeding cycle. Certain phases of the moon influenced grounding of Cory’s Shearwater, with the extent of grounding being reduced during phases of full moon. The percentage of fledglings attracted to lights in relation to the fledglings produced annually varied between species and years (0‐1.3% for the Madeiran Storm-petrel Oceanodroma castro; 41‐71% for Cory’s Shearwater). Mean adult mortality rates also varied between species (from 0.4% for the European Storm-petrel Hydrobates pelagicus and the Cory’s Shearwater, to 2.3% for the Manx Shearwater Puffinus puffinus). Here we show that light-induced mortality rates are of concern, at least for petrels and small shearwaters. Thanks to efforts involving civil cooperation, 95% of grounded birds have been returned to the wild. To minimize the impact of artificial lights on petrels we recommend several conservation measures: continuing rescue campaigns, alteration of light signatures and reduction of light emissions during the fledging peaks. Furthermore, we recommend that a monitoring program for petrel populations be implemented, as well as further studies to assess the fate of released fledglings and continued research to address why petrels are attracted to lights.

We attached 11 g (1.4% body‐mass equivalent) global location sensing (GLS) archival tag packages to tarsi of 25 breeding sooty shearwaters (Puffinus griseus, titi) on Whenua Hou (Codfish Island), New Zealand during the chick‐rearing period in 2005. Compared with chicks reared by non‐handled adults that did not carry tags, deployment of tags on one or both adult parents ultimately resulted in 35% reduction in chick body mass and significantly reduced chick skeletal size preceding fledging (19 April). However, body mass between chick groups was not significantly different after controlling for skeletal size. Effects on chicks were more pronounced in six pairs where both parents carried tags. Chick mass was negatively related to the duration that adults carried tags. In this study, none of the chicks reared by pairs where both parents were tagged, 54% of chicks reared by pairs where one parent was tagged, and 83% of chicks reared by non‐handled and non‐tagged parents achieved a previously determined...

The risk of seabird bycatch in trawl fisheries is increased by high numbers of seabirds attending vessels to feed on fish waste discharged. We conducted an experimental test of whether mincing fish waste prior to its discharge from a factory trawler reduced the number of seabirds attending the vessel. The trial was conducted on a mid-water trawler targeting hoki ( Macruronus novaezelandiae ) in New Zealand waters, and the experiment compared three treatments (1) discharging ‘unprocessed’ waste (fish offal and whole discards), (2) mincing all waste to a small particle size before discharge, or, (3) converting all waste to fishmeal and reducing discharge to sump water. The response to the experimental treatments was determined using seabird abundance within a 40 m-radius semi-circular area centred on the vessel stern. Mincing reduced the numbers of large albatrosses ( Diomedea spp.) feeding astern of the vessel, but had no significant effect on other groups of seabirds. In contrast, reducing discharge to sump water resulted in a significant reduction in numbers of all groups of seabirds. In particular, the abundance of the small albatross group (principally Thalassarche spp.), and some smaller procellarids (e.g. sooty shearwater, Puffinus griseus , and white-chinned petrel, Procellaria aequinoctialis ), was reduced to less than five percent of the number that were within the sweep area when unprocessed discharge was released. While mincing significantly reduced the abundance of large albatrosses at the vessel stern, relatively small numbers of these birds attend trawl vessels in New Zealand waters and associated bycatch rates are low. In contrast, reducing the quantity of fish waste discharge by mealing resulted in reduced abundances of a wide range of seabirds at the vessel. Therefore, compared to mincing, we recommend fish waste retention as a more effective management strategy for reducing seabird bycatch.

Between 2001 and 2006, we systematically sampled the entire coast of Whenua Hou, a rugged offshore island in southern New Zealand, to estimate the population densities of sooty shearwaters (Puffinus griseus) and mottled petrels (Pterodroma inexpectata) by counting the entrances of breeding burrows. A two‐step regression modelling process using binomial errors was used to predict the presence of a colony, and a normal general linear model was used to predict the density of entrances within colonies. Aerial photography, GIS and a Digital Elevation Model were used to extract relevant habitat and location variables, and a combination of both regression models was used to predict the density of breeding burrows within each 5.32 m2 pixel on the island. This complex GIS and habitat prediction modelling approach gave population estimates very similar to a more traditional simple area extrapolation method and gave no improvement in precision. However, correction for the slope of the land increased our sim...

Despite long‐held concerns about the effects of researchers on breeding birds, few studies have focused on the impact of investigators on Procellariiformes. In this review, we summarise published investigations concerning the effects of investigators on physiology, behaviour, reproductive success, offspring quality, and population trends of procellariiform seabirds. Many of the smaller procel‐lariid taxa, such as storm‐petrels (Hydrobatidae, and some shearwater Puffinus species) are particularly sensitive to handling during the incubation period, resulting in lowered reproductive success, burrow shifts, and increased divorce between pairs. However, repeated handling of chicks does not seem to have a discernible effect on chick quality. In larger procellariiforms, the presence of researchers within the breeding colony is associated with significant increases in heart rates. Therefore, researchers seeking unbiased estimates of demographic and ecological parameters of birds should be encouraged to m...

This study of customary harvests of sooty shearwater Puffinus griseus chicks by Rakiura Maori compares the utility of Traditional Ecological Knowledge (TEK) and ecological science for understanding patterns in prey availability. We recorded TEK of 28 muttonbirders about emergence patterns and variation in chick size at different aspects of 14 breeding islands and in their coastal fringe compared to inland areas. Spatial and temporal variation of chick availability were measured using the methods of ecological science in the 2001 harvest season across Putauhinu Island, south west of Rakiura, New Zealand. As predicted by TEK, titi emerged earlier from west than east coast locations on Putauhinu. Scientific measures were also consistent with an earlier emergence in coastal compared to inland areas as asserted by TEK, but conclusive inference is potentially confounded by movement of chicks between burrows just before fledging. A TEK construct predicting heavier chicks on the west coast was not suppor...

We estimated the change in abundance of sooty shearwater (titi, Puffinus griseus) at six Rakiura Titi Islands, New Zealand, by comparing historical and recent surveys of the density of entrances to breeding burrows. We found evidence that entrance density between 1994 and 2006 was lower than it was between 1961 and 1976. Our overall estimate of the annual rate of change in burrow entrance density is ‐1.0% (95% CI ‐2.3 to ‐ 0.1%). Declines have been slower on four islands where Rakiura Maori maintain a traditional harvest of sooty shearwater chicks ("muttonbirding") compared with three unharvested islands. Density‐dependent population processes may explain this difference: rates of decline have been faster in areas of relatively high initial entrance density, and historically the harvested islands have had lower initial density. There was a strong, apparently linear, relationship between entrance density and chick density on breeding colonies, so changes in entrance density probably do indicate a ...

Sooty shearwater (Puffinus griesus, titi) abundance, harvest levels and chick mass were monitored repeatedly on Putauhinu Island, south‐west of Rakiura (Stewart Island) between 1997 and 2005. Putauhinu is the second largest of the Titi Islands and has a relatively high density of chicks distributed over most of the island, so it supports what is likely the second‐largest population of sooty shearwaters in the Rakiura region (after Taukihepa, Big South Cape Island). Rakiura Maori harvested chicks from five “manu” (family birding areas) that covered 56% of the 128.4 ha of breeding colony of the island. Chick density was lower on the unharvested area in the interior of the island than on harvested areas. Burrow entrance density was higher where there was more ground cover (mainly fern) vegetation, but these areas had lower burrow occupancy, so overall chick density was similar at different levels of ground cover. Twenty‐six harvesters present on Putauhinu in 2005 took 31 280 chicks in total, equival...

According to life history theory, it is particularly important for long-lived iteroparous species to balance effort invested in reproduction against risks to future reproductive potential, leading to a conflict between investment in current versus potential future offspring. If providing care for offspring entails a risk of predation, parents must compromise between ensuring offspring growth and survival and ensuring their own survival. We addressed three hypotheses for the outcome of this conflict, which focus on different costs and benefits, and relate variation in parental effort to: (1) the parent's own risk of predation; (2) the reproductive value of the offspring; and (3) the harm that offspring would suffer in the absence of such care. We tested these hypotheses using Manx shearwaters, Puffinus puffinus, which, in common with many burrow-nesting seabirds, are active above ground only at night as a means of reducing attacks by diurnal avian predators. We found that parents were far less likely to return to the colony on moonlit nights, when they were vulnerable to such predators, and tended to delay their arrival until after moonset, which strongly supported hypothesis (1). Also, parents of chicks in good condition were more likely to attend the burrow on moonlit nights than those of chicks in poor condition, which supported hypothesis (2) but not hypothesis (3). Growth of chicks was suppressed on clear nights around the full moon, such that they experienced well-below average growth during one week in four. This could help explain the accumulation of fat stores by the chick that has evolved in some nocturnal seabirds.

The Sooty Shearwater (Puffinus griseus), also known in New Zealand as tītī or muttonbird, is an abundant, long-lived, trans-equatorial migrant that breeds in colonies in the southern hemisphere during the austral summer and migrates to and forages in the North Pacific Ocean during the boreal summer. That populations of Sooty Shearwaters have been declining has been indicated by falling oceanic counts, and reduced burrow density and declining rates of chick harvest of Rakiura Māori muttonbirders. Accurate estimation of adult survival rate of Sooty Shearwaters is vital if we wish to use a demographic model to help understand the decline and manage the population. Mark–recapture studies were carried out at three breeding colonies: Taiaroa Head, Whenua Hou and The Snares, all in southern New Zealand. Analysis of the data generally involved the use of models in which both transience and trap-dependence were allowed for. In addition, birds were split into two groups, according to whether they had been caught on the surface or under an inspection hatch that was placed over a breeding chamber. Our estimates of the level of transience suggest that a large portion of the population at each colony is composed of juvenile and pre-breeding birds. Model-averaged estimates of the survival rate for resident birds were 0.917 (95% C.I.: 0.860–0.973) at Taiaroa Head, 0.966 (0.933–0.997) at Whenua Hou, and 0.961 (0.706–0.996) at The Snares. A combined estimate for The Snares and Whenua Hou is 0.952 (0.896–0.979). Our estimates are higher than earlier estimates of survival for Sooty Shearwaters and congeners, presumably because transience has been more adequately accounted for than in earlier mark–recapture models.

We examined trends in the abundance and distribution of 12 species of marine birds around the Pribilof Islands, southeastern Bering Sea, over the period from 1977 to 2004. We contrasted patterns among piscivores and planktivores and related these to known and hypothesized changes in the abundance and distribution of prey in the vicinity of the islands. Planktivorous and piscivorous species of marine birds showed different patterns of abundance over time. Planktivorous seabirds that breed away from the Pribilof Islands (e.g., short-tailed shearwaters [Puffinus tenuirostris], fork-tailed storm-petrels [Oceanodroma furcata] and red phalaropes [Phalaropus fulicarius]) were scarce in the 1970s, were abundant in the 1980s, and declined in abundance in the 1990s and from 1999 to 2004. Planktivorous alcids combined (parakeet [Aethia psittacula], crested [A. cristatella] and least [A. pusilla]) that breed on the Pribilof Islands showed a similar remarkable four-fold increase from the 1970s to the 1980s, but then a small increase into the 1990s followed by a rapid decline in the 2000s to numbers similar to those present during the 1970s. The abundance of piscivores kittiwakes (Rissa spp.) and murres (Una spp.) was high in the 1970s and declined through the 1980s, 1990s and 2000s. In 1999 and 2004, the total number of all seabirds at sea around the Pribilof Islands was well below the numbers seen at any other survey period. We hypothesize that changes in the abundances and types of seabirds present through time reflect changes in the structure of the marine ecosystem of the eastern Bering Sea shelf. We suggest that changes in pathways of energy flow may be responsible for these shifts, though the possibility that there has been a reduction in productivity cannot be ruled out given the scarcity of available data.

Many seabirds are killed or injured by fishing gear, contributing to the high proportion of threatened seabirds. This study estimates the impact of the South African deep-water hake Merluccius spp. trawl fishery on seabirds. At least 30 birds were killed in 190 h of dedicated observations of trawl warps during 2004 and 2005. Most were killed when their wings were entangled around the trawl warp and they were dragged under by the force of the water passing over the warp. Albatrosses were killed most frequently: shy albatrosses Thalassarche cauta (43% of all birds killed) and black-browed albatrosses Thalassarche melanophrys (37%), with smaller numbers of white-chinned petrels Procellaria aequinoctialis (10%), Cape gannets Morus capensis (7%) and sooty shearwaters Puffinus griseus (3%). Mortalities occurred mainly during dumping of fishery wastes, and were more frequent in winter, when more birds attended fishing vessels. Average mortality rates were 0.56 (95% confidence interval 0.32–0.82) birds killed per hour during dumping in winter, 0.21 (0.07–0.38) during dumping in summer and 0.09 (0.02–0.19) when not dumping in winter. No birds were killed in the absence of dumping in summer. Albatrosses suffered a disproportionately high mortality rate, with 15% of birds dragged under drowning, compared with 4% of all other species. Deaths resulting from entanglement in fishing nets mainly affected Cape gannets M. capensis, and occurred at an average rate of 3.0 (0.9–5.4) birds per 100 trawls (n=331 trawls). Serious warp incidents were independent of age among albatrosses, but there was a tendency for immature gannets to have a higher interaction rate than adults. Crude extrapolation suggests that total mortality is c. 18 000 (8000–31 000) birds per year, of which 85% are killed on warps and 15% entangled in nets. These estimates are of the same order of magnitude as estimates of long-line bycatch in South African waters. Mitigation measures have been implemented to reduce mortality in this fishery.

Flocks of seabirds attending commercial bottom long-line fishing operations on the coastal shelf off southeastern Brazil show a greater species diversity during the summer than the winter (16 v 9 species), although the number of birds per flock tended to be greater during the cold season. During the summer, the Spectacled Petrel Procellaria aequinoctialis conspi-cillata was the commonest species, followed by the Great Shearwater Puffinus gravis, Cory's Shearwater Calonectris diomedea, skuas Stercorarius spp. and the Yellow-nosed AlbatrossDiomedea chlororhynchus. During the winter, the White-chinned Petrel Procellaria aequin-octialis, Yellow-nosed Albatross and Black-browed Albatross Diomedea melanophrys were jointly the commonest species. Marked differences in the relative abundance of species were observed between the different sampling periods, probably because of migratory movements but also because of seasonal shifts of the sea currents and the influence of cold fronts. Waters off southeastern Brazil are important feeding areas for some seabird populations nesting in the Tristan da Cunha and Gough group, especially for nonbreeding Spectacled Petrels and post-breeding Yellow-nosed Albatrosses.

SUMMARY In this paper the bird bones collected in three separate localities on St. Helena during the British Ornithologists' Union Centenary Expedition to Ascension Island are catalogued and described. At Prosperous Bay there are deposits which appear to be only a few hundred years old, containing many intact bird bones, referable to Puffinus assimilis/lherminieri, Pelagodroma marina, Sula sula, Fregata ariel, and a new rail Aphanocrex podarces. In Dry Gut, north of Bencoolen, are apparently older deposits with bones of a medium-sized Pterodroma sp. and a humerus of Upupa epops. On Sugar Loaf Hill are extensive deposits which may be very old, containing fragmentary bones of a large Puffinus sp., of Puffinus assimilis/lherminieri, Pelagodroma marina, and at least one species of columbid. There is now evidence that thirteen species of oceanic birds have bred on St. Helena at some time (plus one—Sula leucogaster—whose status is still uncertain). Of these, only six species are now known to breed on the island, though two more may do so. The only surviving native land-bird is Charadrius sanctae-helenae, but at least three additional species were present in the past.