Storm Petrel Research Articles

Fat reserves and perceived predation risk in the great tit, Parus major.

The fat reserves of small birds are built up daily as insurance against starvation. They are believed to reflect a trade-off between the risks of starvation and predation such that in situations of high predation risk birds are expected either to reduce their fat reserves in response to mass-dependent predation risk or to increase them in response to foraging interruptions. We assessed the effect on fat reserves of experimentally altering the perceived (but not the actual) risk of predation of wild great tits at a winter feeding site. The perceived predation risk was alternated between 'safe' and 'risky'. Increasing the perceived risk of predation involved 'swooping' a model sparrowhawk over the feeder at four unpredictable times each day using a remote mechanism We produce evidence that the experiment was suceessfull in altering the perceived risk of predation. As predicted from the hypothesis of mass-dependent predation risk, great tits (Parus major) carried significantly reduced fat reserves during the 'risky' treatment. Furthermore, dominant individuals were able to reduce their reserves more than subordinates. As birds returned to feeders within seconds after a predator 'attack', the reduction in fat reserves cannot be attributed to an interruption in feeding.

Some aspects of the population structure of Storm Petrels Hydrobates pelagicus breeding on a Mediterranean island

Between 1986 and 1998 1,374 adults and 1,708 chicks of Storm Petrels Hydrobates pelagicus have been ringed on Marettimo Is. (Sicily, Italy); 207 (15.1%) adults and 31 (1.8%) chicks were subsequently controlled. Only eight adults (0.6%) were recovered twice in different years after ringing. Site tenacity within the study site was observed, both of individuals ringed as adults and of those ringed as chicks, together with high intrapopulational turnover (neither adults after more than six years since ringing, nor individuals ringed as chicks aged more than seven years were recovered). This helps to explain eight cases of individuals ringed as chicks and recovered as breeding adults between one and three years after fledging.

The planimetric unfold method of fullerene cage structure

Two kinds of planimetric diagrams, which consist of the boat form F6 and F5, the storm petrel form F6 and F5, respectively, were proposed to express the geometric structure of fullerene cage in this study. There are two chief advantages using the diagrams: (i) the spatial symmetrical characteristic of fullerene cage is not destroyed; (ii) the coordination forms of F5 and F6 in the structure can be clearly expressed. This work has laid the foundation for studying the structural geometry of fullerene cage and its quantum chemistry and property.

Conservation value of ringing seabirds in Britain and Ireland

Large numbers of seabirds have been ringed in Britain and Ireland by volunteers and, to a lesser extent, professional ornithologists. At present, the species with about 5,000 or more ringed per year are Guillemot, Storm Petrel, Herring Gull, Puffin, Arctic Tern and Lesser Black‐backed Gull. Storm Petrel, Cormorant, Shag, Herring and Lesser Black‐backed Gulls and Guillemot provide in excess of 200 recoveries per annum per species. The wintering grounds and general migration routes of most British and Irish seabirds are known but most analyses are rather dated. This might hinder the prediction of effects of threats to British and Irish Seabirds arising away from colonies. Recoveries have proved extremely useful in highlighting seabird conservation issues, such as the killing of terns in West Africa and the drowning of auks in fishing nets. The finding of long‐term population studies of colour‐ringed seabirds is under threat. In future we may have to rely more on analyses of metal ring recoveries for obtaining the demographic data that are essential if the United Kingdom and Republic of Ireland are to conserve their internationally important seabird populations and meet their international obligations. Ringing studies have shown that seabirds are less philopatric than once thought. This may lessen the effect of a local disaster at a colony, but, conversely, other colonies could be influenced by such a disaster. A recent atlas of recoveries of Guillemots ringed in Scotland shows how such maps can be used to assess the seabird colonies that are at risk in a major disaster. Another analysis indicates how recoveries can be used to assess the effects of an unusually severe mortality event on a breeding population. Few papers using the results of seabird ringing have been published in the last five years. Ringing coverage should be maintained at near the current level and a formal review of sample sizes should be undertaken to determine targets for different analytical purposes. More ringing of gulls should be undertaken in Scotland, cliff‐nesting species in England and all species in Ireland. Ringers should be encouraged to ring more adult seabirds and to collect retrap data. Many more analyses of existing data should be undertaken, and published, especially to determine whether the demographic information currently obtained by detailed population studies could be obtained from ring recovery data. Ring subsidies to encourage the ringing of certain species continue to be a useful way of targeting ringing effort towards species of conservation priority.

The Mediterranean Storm Petrel Hydrobates pelagicus melitensis at Cabrera archipelago (Balearic Islands, Spain): Breeding moult, biometry and evaluation of the population size by mark and recapture techniques

The population size of the Mediterranean Storm Petrel Hydrobates pelagicus melitensis breeding on Cabrera archipelago was evaluated by using capture‐recapture techniques (du Feu estimation) with the aid of tape‐lures at the breeding colonies. Both sub‐adult and adult birds were attracted by the tape lures at a similar rate, and both age groups show a high degree of philopatry to their natal site. The recapture of birds ringed in the previous years, that were originally captured as adults or chicks, has provided valuable information for the determination of the age composition of the birds mist‐netted during the breeding season. Sub‐adult birds tend to visit the colonies during the pre‐egg and egg‐rearing stage, while those present at the breeding sites from July on are predominantly adult breeding birds. New information on biometry of the subspecies is given, together with evidence of a breeding moult that includes the flight feathers, and affects sub‐adult non‐breeders and adult breeders. The moult pattern shows clear cut differences in its development and timing for both age groups.

First recorded breeding of Leach's Storm Petrel Oceanodroma leucorhoa in the Southern Hemisphere, at Dyer Island, South Africa

First recorded breeding of Leach's Storm Petrel Oceanodroma leucorhoa in the Southern Hemisphere, at Dyer Island, South Africa

Survey of marine birds and mammals of the South Sandwich Islands

AbstractDuring January and February 1997, two separate surveys of the birds and seals of the South Sandwich Islands archipelago were made, with further data obtained from the northern islands during February 1998. Together, these surveys provide the most recent and accurate estimates of breeding populations of most species, their distributions, and their habitat. Observations were made (1) from a small vessel operating close inshore, which surveyed approximately 92% of the archipelago's coastline, in addition to making shore counts at selected locations; (2) during a six-week shorebased field camp on Candlemas Island; and (3) opportunistically during helicopter-supported landings and airborne operations over all islands in the archipelago. The surveys recorded 16 species of breeding birds, including the first confirmation of breeding by black-bellied storm petrels (Fregetta tropica) and Antarctic terns (Sterna vittata), the second record of incubating king penguins (Aptenodytes patagonicus), and the location of many previously unrecorded seabird breeding sites. The population of chinstrap penguins (Pygoscelis antarctica), at approximately 1.5 x 10 pairs is considerably less than the estimate of 5 x 10 pairs currently in use, and represents about 30% of the world population. Populations of chinstrap penguins, Antarctic fulmars (Fulmarus glacialoides), cape petrels (Daption capense), and snow petrels (Pagodroma nivea) in the South Sandwich Islands are of global significance. Five species of seals were recorded. At the time of the surveys, only Antarctic fur seals (Arctocephalus gazella) were confirmed to be breeding, and several new breeding sites were located. Pup numbers showed a small increase compared with the few earlier records, but the population has not undergone the large increases seen on South Georgia and at sites in the maritime Antarctic. The other four species recorded are considered highly likely to breed either within the archipelago or amongst pack ice that seasonally surrounds the islands.

Influence of phylogeny, diet, moult schedule and sex on heavy metal concentrations in New Zealand Procellariiformes

Mercury, cadmium, zinc and copper concentrations were analysed in the liver and kidney tissues of 14 species of albatross and petrel. These birds were obtained as by-catch of the long-line tuna fishing industry in New Zealand waters, and provided a unique opportunity to compare heavy metal accumulation in a group of closely related species. Mercury levels in the liver of the wandering and royal albatrosses were among the highest recorded for free-living birds. In multiple regression analyses, much of the inter-specific variation in cadmium and mercury levels was related to the importance of Crustacea in the diet, to phylogeny, or to the duration of the moult cycle. Species in which crustacea constituted >33 % of the diet had significantly lower cadmium concentrations in liver tissues, and mercury concentrations in both liver and kidney tissues, than those in which birds consumed mainly or entirely squid and fish. This accords reasonably well with information on relative mercury and cadmium content of prey species. After accounting for dietary variation, Procellariidae (petrels, shearwaters and prions) and Hydrobatidae (storm petrels) still exhibited higher cadmium concentrations in the liver than Diomedeidae (albatrosses). In addition, albatrosses which took more than a year to moult accumulated higher mercury concentrations in their livers, probably because of a restricted ability to excrete mercury into growing feathers.

Ectoparasite Effects on Nestling European Storm-Petrels

-A colony of European Storm-petrels (Hydrobates pelagicus) on Benidorm Island was studied during 1996 breeding season. We experimentally tested whether ectoparasites affected growth and health of nestling stormpetrels. Four species of ectoparasites were found on nestlings; the most common were a dermanyssid mite and the flea Xenopsylla gratiosa. We manipulated ectoparasite loads on chicks by assigning them to one of three treatments: fumigated with insecticide, ectoparasite addition, or control. Nestlings in the fumigated group gained mass at a higher rate than those in the control group, and nestlings from the parasite addition treatment gained mass at the lowest rate. Because slower mass gain may delay fledging or reduce survival, ectoparasites may be an important selective force on European Storm-petrels. Received 31 March 1999, accepted 17 April 1999. Key-words.-Ectoparasites, fleas, growth, hematocrit, mites, European Storm Petrel, Hydrobates pelagicus. Waterbirds 22(2): 297-301, 1999 Research over the last 20 years has demonstrated the influence of parasites on many aspects of host life histories (Price 1980; Loye and Zuk 1991; Moller 1997). In birds, many of the studies have focused on parasitism and host reproductive success (Loye and Zuk 1991; Moller 1990; Merino et al. 1996). Parasitism may affect reproduction of hosts; nestlings supporting high numbers of parasites may grow slower and suffer higher mortality rates (reviewed in Moller et al. 1990; Lehman 1993). In addition, parasitism can be an important cost of coloniality in birds, because high nest densities can enhance transmission of ectoparasites and diseases (Brown and Brown 1986; Shields and Crook 1987). Several works report high costs of parasitism, mainly due to nestling mortality and nest abandonment of colonial seabirds (Converse et al. 1975; King et al. 1977; Feare et al. 1994). In addition, in many underground-nesting seabirds, chicks frequently move between neighboring nests, interacting with other chicks or adults (Winkler and Walters 1983) and increasing the probabilities of horizontal transmission of ectoparasites, a factor related to high parasite virulence (Frank 1996). The European Storm-petrel (Hydrobates pelagicus) is an endangered colonially-nesting seabird that breeds on islands along European coastlines. It is a small, nocturnal petrel that nests in crevices. It raises one chick per breeding attempt; fledging occurs about 63 days after hatching (Davis 1957). Although young chicks tend to remain at their nest-sites, older chicks progressively increase their activity and movements out of the nest (Minguez 1997). During routine field work, a high infestation by ectoparasites was observed on nestlings at two colonies on Benidorm Island (38'30'N, 0008'E), off the Mediterranean coast of Spain, where about 400 pairs of European Storm-petrel breed (Minguez 1994). The aims of this study were to identify the ectoparasite fauna infesting storm-petrels and to investigate whether parasites imposed costs to growing chicks in terms of development rate (wing length and mass attained, increase in growth measures and different rates of growth during experimental treatment). In addition, we checked for differences in the hematocrit value, a measure that may be related to ectoparasite effects and nestling health (i.e. anemia).

Development of playback census methods for Storm Petrels Hydrobates pelagicus

The factors affecting the probability of nest site attendance and response to playback were examined on Mousa, Shetland, during 1996 with the aim of developing a standard method of censusing Storm Petrels using diurnal playback. Nest site attendance by breeding birds peaked at 90% during July. Site attendance by non-breeding birds was much lower at 15% and this increased as the season progressed. Studies of breeding phenology at colonies throughout Britain and Ireland demonstrated that the average laying dates at most colonies were in late June, but those at Mousa were on average two weeks earlier and at Inish Glora one week later. This analysis also suggested that site attendance is highest in mid-July and so this represents the best time of year to conduct playback censuses at colonies in Britain and Ireland. Rates of response to playback of the male purr call were highly variable, with evidence for effects of the environment, colony location, playback equipment and year. This suggests that the application of a single correction factor to playback survey data collected at different colonies is likely to result in serious errors in estimation of population status. We recommend that the probability of detecting a nest is examined during each survey so that a colony-specific correction factor can be applied to the census data.

Migration and arrival of immature Storm Petrels Hydrobates pelagicus in Shetland

Mark‐recapture estimates of the size of a Storm Petrel population which is attracted to tape‐lures in Shetland in early July average 8,000 birds. There was a massive influx towards the end of July, which increased the population estimates to about 123,000 birds, which then declined to about 20,000 birds until sampling ceased in August.

First record of Leach’s storm petrel Oceanodroma leucorhoa for King George Island, South Shetlands, Antarctica

First record of Leach’s storm petrel Oceanodroma leucorhoa for King George Island, South Shetlands, Antarctica

Speciation through temporal segregation of Madeiran storm petrel (Oceanodroma castro) populations in the Azores?

Madeiran storm petrelsOceanodroma castrobreed on three small islets in the Azores: Vila, off Santa Maria, and Praia and Baixo, off Graciosa. Analysis of data on brood patch, incubation periods, chick body size and recaptures of adults provides evidence of the existence of two distinct populations (hot– and cool–season) breeding annually on Baixo and Praia, out of phase by four to five months and overlapping in colony attendance during August and early September; on Vila only the cool–season population is present. Analyses of adult morphology indicate highly significant phenotypic differentiation between the sympatric hot– and cool–season breeders, whereas an almost complete phenotypic uniformity characterizes allopatric breeders within the same season. The hot–season birds are 10% smaller in egg and body mass but have longer wings and tails than cool–season birds. The two groups were readily separated by discriminant analysis. The preference to breed in the cooler season is interpreted as a consequence of greater food availability in that period. Morphological differentiation between seasonal populations is interpreted as an adaptative response to different environmental conditions in the two seasons. The hypothesis is given that the hot–season population has evolved from the cool–season population owing to density–dependent constraints on crowded colonies, forcing birds to time–share nest sites. These populations may represent a case of sympatric speciation through temporal partitioning of reproduction and may be better treated as sibling species.

A Theoretical Analysis of Sea-anchor Soaring

This study presents a concise mathematical model that accounts for sea-anchor soaring, a special flight technique used by sea birds, in particular storm petrels. Conventional wing theory is used to reveal the mechanics of sea-anchor soaring. The feasibility and existence of an equilibrium are summarized by formulae giving the wind velocity criteria. The stability of the equilibrium is also revealed: among two possible equilibria, the equilibrium at the very low velocity to water is shown to be stable. Numerical examples show the following: sea-anchor soaring is almost always stable; Wilson's storm petrel can soar at 0.256 ms−1in wind with 4.79 ms−1under the best conditions. Larger sea-birds like albatrosses need gusty winds to soar, but such strong winds make the sea choppy and hence prevent soaring. Foot-web size regulates the size of a bird utilizing sea-anchor soaring at low velocities to water.

Flight speed of seabirds in relation to wind speed and direction

We studied flight speed among all major seabird taxa. Our objectives were to provide further insight into dynamics of seabird flight and to develop allometric equations relating ground speed to wind speed and direction for use in adjusting seabird density estimates (calculated from surveys at sea) for the effect of bird movement. We used triangulation at sea to estimate ground speeds of 1562 individuals of 98 species. Species sorted into 25 “groups” based on similarity in ground speeds and taxonomy. After they were controlled for differences inground speed, the 25 groups sorted into eight major “types” on the basis of response to wind speed and wind direction. Wind speed and direction explained 1664% of the variation in ground speed among seabird types. For analyses on air speed (ground speed minus apparent wind speed), we divided the 25 groups according to four flight styles: gliding, flap‐gliding, glide‐flapping and flapping. Tailwind speed had little effect on air speed of gliders (albatrosses and large gadfly petrels), but species that more often used flapping decreased air speed with increase in tailwinds. All species increased air speeds significantly with increased headwinds. Gliders showed the greatest increase relative to increase in headwind speed and flappers the least. With tailwind flight, air speeds were greatest among species with highest wing loading for each flight style except gliders, which showed no relationship. For headwind flight, species with higher wing loading had higher air speeds; however, the relation was weaker in flappers compared with species using some amount of gliding. In contrast, analyses for air speed ratio (i.e. difference between air speed in acrosswinds [with no apparent wind] and speed flown into headwinds, or with tailwinds, divided by speed acrosswind) revealed that among species using some flapping, and with lower wing loading (surface‐feeding shearwaters, small gadfly petrels, storm petrels, phalaropes, gulls and terns), adjusted air speeds more than those with higher wing loading (alcids, “diving shearwaters”, “Manx‐type shearwaters”, pelicans, boobies and cormorants). As a result, most flappers of low wing loading flew much faster than Vmr (the most energy efficient air speed per distance flown) when flying into headwinds. We suggest that better‐than‐predicted gliding performance with acrosswinds and tailwinds of large gadfly petrels, compared with albatrosses, resulted from a different type of “soaring” not previously described in seabirds.

Energy expenditure, body‐weight and foraging performance of Storm Petrels Hydrobates pelagicus breeding in artificial nesting chambers

Many avian species, such as Storm Petrels Hydrobates pelagicus, are intolerant of disturbance at the nest, which complicates the collection of data relating to metabolic rate and the use of body reserves during incubation. I describe the design of an artificial nest chamber, which is simple and inexpensive to construct and facilitates the collection of such data. Eighty‐one nest chambers situated in a large colony of breeding Storm Petrels had high occupancy rates (29/81 in each of 2 years), and the breeding success of birds nesting in boxes was similar to that of pairs nesting in natural crevices. Direct measurement of carbon dioxide production using standard respirometry techniques and estimations of metabolic rate based on the rates of mass loss during incubation indicated close agreement between the two methods of estimating energy consumption. Assuming the metabolic requirements during incubation are furnished entirely from stomach oil, 76% of the daily mass lost represented stomach oil catabolism. The duration of incubation shifts was unrelated to the body mass, and presumably to body reserves, of Storm Petrels on arrival at the nest. Shifts were usually terminated by the return of the foraging partner. The body mass of birds returning from foraging was relatively constant and was unrelated to the amount of time spent foraging at sea, indicating that the decision rule to return from foraging was the acquisition of a threshold level of body mass (about 31 g). There was a negative relationship between the duration of foraging trips and the body mass of Storm Petrels at departure from the nest and a positive relationship between trip duration and the net mass gain at sea. The use of nestboxes based on the design described here would have a wide variety of applications in facilitating data collection for many cavity‐or burrow‐nesting species which are sensitive to disturbance.

Assessing the population size of the European storm petrel () using spatial autocorrelation between counts from segments of criss-cross ship transects

Van der Meer, J., and Leopold, M. F. 1995. Assessing the population size of the European storm petrel (Hydrobates pelagicus) using spatial autocorrelation between counts from segments of criss-cross ship transects. ‐ ICES J. mar. Sci., 52: 809‐818. European storm petrels were counted on criss-cross ship transects on the continental shelf between Ireland and Spain. No element of randomisation was involved in the selection of the sampled area. A geostatistical model which explicitly considers the spatial autocorrelation between observations from transect segments, was therefore used to predict population size in the study area. The model also provides standard errors of the prediction. Although some of the underlying assumptions of the model were questionable, several alternative approaches yielded almost similar predictions, suggesting model robustness. The prediction of the total number of European storm petrels present in the study area is equivalent to 255 000 breeding pairs. This is much higher than previous estimates of the total breeding population of the region, ranging from 50 000 to 100 000 pairs. ? 1995 International Council for the Exploration of the Sea

Dimethyl sulphide as a foraging cue for Antarctic Procellariiform seabirds

MANY Procellariiform seabirds make their living flying over vast expanses of seemingly featureless ocean waters in search of food. The secret of their success is a mystery, but an ability to hunt by smell has long been suspected1–7. Here we present experimental evidence that Procellariiform seabirds can use a naturally occurring scented compound, dimethyl sulphide, as an orientation cue. Dimethyl sulphide has been studied intensely for its role in regulating global climate8–11 and is produced by phytoplankton in response to zooplankton grazing12. Zooplankton, including Antarctic krill (Euphamia super ha)13, are in turn eaten by seabirds and other animals14. Results from controlled behavioural experiments performed at sea show that many Procellariiforms can detect dimethyl sulphide, and that some species (for example, storm petrels) are highly attracted to it. To our knowledge, this constitutes the first evidence that dimethyl sulphide is part of the natural olfactory landscape overlying the southern oceans.

Experimental evidence for regulation of food delivey to storm petrel, Hydrobates pelagicus, nestlings: the role of chick body condition

The existence of a possible feedback mechanism, causally relating the nutritional status of nestling British storm petrels to the subsequent rates of food provisioning by their parents, was examined using a supplementary feeding experiment. There were no differences in parental provisioning behaviour between experimental and control groups before the supplementary feeding regime commenced. Thereafter, chicks receiving supplementary food showed higher levels of body condition (attributable to the experimental protocol), and consequently received smaller and less frequent meals from their parents than controls. The total amount of food received by the experimental group (parental delivery plus supplementary food) was similar to the amount delivered by control parents, indicating compensatory regulation of provisioning. These results support earlier findings at the same colony but are in contrast to similar studies on other procellariiform species elsewhere. The demonstration of regulation of food delivery casts doubt on hypotheses relating slow growth and lipid accumulation of procellariiform nestlings to scarce and unpredictable food resources, and indicates that more recent explanations relating lipid deposition to chronic overprovisioning by the adults are untenable for this species.

Food Delivery to Nestling Storm Petrels: Limitation or Regulation?

1. Temporal variation in food delivery to nestling British Storm Petrels Hydrobates pelagicus was examined by repeated overnight weighing, to determine whether provisioning rates were likely to be determined primarily by the availability of food to adults foraging at sea or by the chick's immediate food requirements. 2. The interval between successive feeds was short, indicating a relatively small foraging range. 3. There was a negative correlation between mean daily wind speed (considered to reflect foraging conditions) and the proportion of adults returning to feed their chicks (but not meal size) the following night, but this was heavily dependent on a few extreme values. There was no correlation between wind speed and feeding frequency during more typical weather conditions. 4. Chicks' requirements for body maintenance increased with chick age, up to about 39 days post-hatching. This was paralleled by an increase in the amount of food consumed on nights when adults fed their chicks, but not feeding frequency. 5. There was evidence of regulation of feeding frequency in relation to recent feeding history. 6. The finding that the frequency of feeding visits to the colony appears to be regulated in response to the chick's short-term nutritional requirements implies that the achieved feeding rates are below the limits set by food availability and that the low rates of delivery may not be the result of low availability of food at sea