Thesis (Ph. D.)--University of Western Australia, 2004. / Title from PDF t.p. (viewed Feb. 7, 2006). Includes bibliographical references.

Chapter 1 is purely introductory and gives a brief account of the taxonomic status of the subject of this thesis, the Manx Shearwater Puffinus puffinus. The main study area, Skokholm Island, Pembrokeshire is described and a general account of what is already known of the breeding biology of the Manx Shearwater is provided as a background to the more detailed studies described in the present work which was continued over five breeding seasons, 1973-1977. In Chapter 2 I demonstrate that male and female Manx Shearwaters differed in the length of their bills and tarsi but not in wing length. However most of the chapter is concerned with the weights and measurements of shearwaters, most of which were of known age but unknown sex, caught at the colony by night. In 1973 and 1974 the weight of all age groups was highest in March and then declined to a minimum in June and July. Weight increased slightly in August. It was generally true that the older a bird was, the heavier it was in any particular month, and this effect appeared to hold good until the birds were 8-10 years old. Unlike weight, bill and wing length did not alter with age. The implications of these results are discussed in the light of current hypotheses concerning the delayed onset of breeding shown by many seabirds including the Manx Shearwater. In the pre-laying period, covered by Chapter 3, both male and female Manx Shearwaters lost weight up until about two weeks before laying. Males lost weight more rapidly than females and this was related to the fact that males visited the burrow more regularly. In the two weeks prior to laying the male continued regularly to visit the burrow at night but the female was virtually absent from the colony; it appears that she may travel into the Bay of Biscay to feed during this period of absence. In the pre-laying period the weight of breeding birds was not different from the weight of birds which have bred formerly but which were not known to be breeding during the current season. However, breeding birds tended to be heavier than birds which started to breed in a future year. To test the possibility that young birds may be prevented from breeding by a shortage of burrows artificial burrows were dug, and some were occupied by young birds, probably breeding for the first time. A burrow-blocking experiment was also carried out. The possibility that competition for burrows was greater in an area of higher as opposed to lower burrow density was investigated by comparing the pre-laying attendance pattern of breeders in the two areas. No difference was found. Chapter 4 shows that the breeding success of newly-formed pairs was lower than that of established pairs, mostly because newly-formed pairs were less successful at incubation. The lower success of new pairs was not due to the new pairing per se but to the fact that such new pairs tended to include birds without previous breeding experience. Thus experienced birds may avoid the disadvantageous consequences (to breeding success) of forming a new pair if they mate with another experienced bird, and this they did. Divorce and change of breeding burrow were both more likely after a breeding failure than a success. Both the laying date and egg volume of individual female Manx Shearwaters varied little from year to year, once the first few years of breeding were passed. I am unable to reconcile this finding with Perrins' (1970) suggestion that the laying date of the female Manx Shearwater is determined by the difficulties she may encounter early in the season in building up sufficient food reserves to form the egg. Instead I propose that, although early laying would be advantageous from the point of view of chick survival (Perrins 1966), the shearwaters do not lay earlier because of the difficulties that would be encountered in successfully incubating an early egg. Evidence supporting this idea is presented. In each of the four study years the fledging weight of chicks declined as the season progressed, as described in Chapter 5. Various lines of evidence, including an egg-swapping experiment, support the view that this decline was mostly due to a deterioration of feeding conditions late in the season, rather than to a tendency for parents less proficient at rearing heavy young to breed later. It seems that date of fledging and weight at fledging may both influence the fledgling's chances of survival but I am unable to determine the relative importance of these two factors. Different pairs of shearwaters differed in their ability to feed chicks, but chick-feeding performance was not related to age or breeding experience. Chapter 6 evaluates the parameters necessary for the construction of a life table. Of the chicks which fledge from Skokholm at least 25 % survive to breed on Skokholm, whilst adult survival is about 90 %. About 20 % of those adults known to be alive and to have bred previously do not breed in any one year- The age of first breeding, currently about six, has increased over the past ten or fifteen years. Among the birds which have been ringed as chicks on Skokholm and which bred there during the study period there was a 2:1 ratio of males to females. I suggest that about half the females fledging from Skokholm settle to breed in other colonies. The body measurements (used as an indicator of sex) and abundance of Skokholm-ringed birds on nearby Skomer Island support this hypothesis. The Manx Shearwater life table is therefore constructed to take account of immigration to and emigration from the Skokholm colony. Recruitment to the breeding population and loss by mortality are roughly equal. Chapter 7 shows that the calls given by male and female Manx Shearwaters were different. The response of other shearwaters to these calls was investigated by means of playback experiments. Females recognized the calls of their male mates but I am unable to show a selective response of males to the calls of their female mates. This difference is considered to be related to the different roles of the two sexes and to be associated with the fact that most calls heard from the ground were given by males whilst most calls uttered in flight were probably given by females. There is no evidence that nestlings can recognize the calls of their parents. The value of colonial breeding is considered in the concluding Chapter 8. It seems that Manx Shearwaters in the dense Main Colony experienced a lower rate of predation, but they did not have greater reproductive success than those breeding in areas of lower burrow density elsewhere on the island. Although nesting habitat on Skokholm is not fully utilised there may be a limited supply of breeding burrows available. This would create competition for burrows which, together with competition for food, is suggested as an important influence on the breeding biology of the Manx Shearwater. There are four appendices. The first shows that birds first caught in the colony at two years old were caught earlier in the year when three years old than those which were caught for the first time at three. Similarly, birds which have been caught when two or three years old were caught earlier in the year when four years old than those birds which were caught for the first time at four. These differences in time of return to the colony appear not to be associated with sex. Appendix 2 discusses the relationship between the body size of offspring and their parents. In the Manx Shearwater it appears that about three-quarters of the phenotypic variance of body size is due to genetic causes, and may therefore be inherited. Appendix 3 describes a simple experiment designed to test the possibility that vision may be one sense used by Manx Shearwaters attempting to locate their breeding burrow. The result of the experiment was positive but more extensive tests would be required to assess the relative roles of vision and any other senses that may be employed in burrow location. Appendix 4 describes an unsuccessful visit to the Basque coast of northern Spain to assess the status of the Manx Shearwater in the south-east corner of the Bay of Biscay in the pre-laying period, late April. I tentatively suggest that it is only in exceptional circumstances that many shearwaters feed south of about 46° N.

Rakiura Maori continue a centuries old harvest of titi chicks (sooty shearwater, Puffinus griseus) which is governed primarily by Traditional Ecological Knowledge (TEK). The sustainability of titi harvesting is of high cultural, social and ecological importance. Some commentators view contemporary use of TEK as insufficient to ensure sustainability because it is no longer intact, too passive, and/or potentially inadequate to meet new ecological and technical challenges. Such assertions have been made in the absence of detailed description of TEK and associated social mechanisms. This thesis describes Rakiura Maori TEK practices and management systems that are in place and asks whether such systems are effective today, and whether they will remain effective in future. Ecological, social and cultural factors are intertwined in cultural wildlife harvests so the methodology used was a combination of quantitative ecological methods and semi-directive interviews of 20 experienced harvesting elders. The research also used ecological science to evaluate potential harvest monitoring methods and to determine what sets the limits on harvest. These ecological studies focused on harvesting by four families on Putauhinu Island in 1997-1999. Harvest is divided into two parts. In the first period (�nanao�) chicks are extracted from breeding burrows during daytime. In the second period (�rama�) chicks are captured at night when they have emerged from burrows. Nanao harvest rates only increased slightly with increasing chick densities and birders� harvest rates varied in their sensitivities to changing chick density. Although harvest rates can only provide a general index of population change a monitoring panel, with careful selection of participants, may be the only feasible way to assess population trend and thereby harvest sustainability or the resource�s response to changed management. Rakiura Maori harvesting practice constitutes common property resource management based on birthright and a system of traditional rules. Protection of island habitat and adult birds, and temporal restricitions on harvest are considered most important. Legislation and a belief system of reciprocity and connection to ancestors and environment aid enforcement of the rules. Ecological knowledge is learnt through observation, hands-on experience and storytelling. Younger Rakiura Maori now spend less time harvesting which puts pressure on the transmission of knowledge. Paradoxically, use of modern technology for harvesting aids transfer of essential skills because it is easier and faster to learn, thereby contributing to the continuance of a culturally important harvest. Limits on harvest are passive, with the numbers of chicks taken determined by the time spent harvesting and processing. Processing is more limiting during the rama period. Future innovations that decrease the time to process each chick during rama could greatly increase the total number of chicks caught. Recently introduced motorised plucking machines decrease the time required to pluck each chick. However, on Putauhinu Island, use of plucking machines did not increase the number of chicks harvested, indicating social mechanisms were also limiting. Elders identified changing values between the generations, which may reduce the future strength of social limitations on harvest pressure. Global climate change may reduce the predicability of traditional knowledge. Rakiura Maori have identified this risk and sought to examine ecological science as a tool to complement traditional knowledge for monitoring harvest sustainability. Climate change, declining tītī numbers and potential changes in technology or markets all threaten the effectiveness of current social limits to harvest. Rakiura Maori have previously shown the ability to adapt and must look to add resilience to their institutions to ensure we keep the titi forever.

The marine birds comprising the order Procellariiformes are an ancient and diverse assemblage. A large proportion are both nocturnal and burrow-nesting at their breeding colonies, where in sharp contrast to their behaviour at sea, they are highly vociferous. Virtually nothing is known regarding the adaptive features of this process. Various aspects of vocal behaviour have therefore been investigated from 1981 to 1983 for seven species at breeding stations in both the boreal and sub-tropical North Atlantic Ocean. In addition, the problem of how these birds return to their correct burrows at night has been considered. A detailed study was conducted on the Manx Shearwater Puffinus puffinus. Various approaches showed that immatures contribute most to the calling heard. Males establish and defend burrows, but both sexes partake in aerial calling. Calling at ground level serves both sexual and territorial functions, whereas aerial calling is probably mainly concerned with sexual advertisement. Some males are more silent in flight than others. These probably represent birds as yet without burrows, perhaps the youngest age classes. Flighting activity probably expedites the acquisition of burrows and mates in these birds which are awkward on land, and aerial calling probably improves signalling efficiency in attracting mates. Six other species (Bulweria bulwerii, Calonectris diomedea, Puffinus assimilis, Hydrobates pelagicus, Oceanodroma castro, Pelagodroma marina) were studied. As with Puffinus puffinus, sexual differences in voice exist for all except Bulweria and Pelagodroma, which also lack aerial calls. Thus a functional link exists between flight calls and their sexual divergence. Selection probably favours such divergence in species where males leave burrows to display in flight; the sexual identity of those species whose males do not is unambiguous as they remain in burrows and call. The calls of Puffinus puffinus and Hydrobates pelagicus were compared at local and regional levels. Divergence exists between but not within islands. Vocal drift in Puffinus puffinus is also apparent after several years. The calls of the nocturnal Procellariiformes are reviewed and discussed in relation to their systematics. The potential use of calls in petrel systematics is also evaluated and shown to be useful. Observations on Puffinus puffinus showed that olfactory and auditory cues are not used for burrow homing. Experiments also confirmed this, and point to sufficient visual development in this species, although other senses may be emphasised in different ecological situations.

Rakiura Maori continue a centuries old harvest of titi chicks (sooty shearwater, Puffinus griseus) which is governed primarily by Traditional Ecological Knowledge (TEK). The sustainability of titi harvesting is of high cultural, social and ecological importance. Some commentators view contemporary use of TEK as insufficient to ensure sustainability because it is no longer intact, too passive, and/or potentially inadequate to meet new ecological and technical challenges. Such assertions have been made in the absence of detailed description of TEK and associated social mechanisms. This thesis describes Rakiura Maori TEK practices and management systems that are in place and asks whether such systems are effective today, and whether they will remain effective in future. Ecological, social and cultural factors are intertwined in cultural wildlife harvests so the methodology used was a combination of quantitative ecological methods and semi-directive interviews of 20 experienced harvesting elders. The research also used ecological science to evaluate potential harvest monitoring methods and to determine what sets the limits on harvest. These ecological studies focused on harvesting by four families on Putauhinu Island in 1997-1999. Harvest is divided into two parts. In the first period (�nanao�) chicks are extracted from breeding burrows during daytime. In the second period (�rama�) chicks are captured at night when they have emerged from burrows. Nanao harvest rates only increased slightly with increasing chick densities and birders� harvest rates varied in their sensitivities to changing chick density. Although harvest rates can only provide a general index of population change a monitoring panel, with careful selection of participants, may be the only feasible way to assess population trend and thereby harvest sustainability or the resource�s response to changed management. Rakiura Maori harvesting practice constitutes common property resource management based on birthright and a system of traditional rules. Protection of island habitat and adult birds, and temporal restricitions on harvest are considered most important. Legislation and a belief system of reciprocity and connection to ancestors and environment aid enforcement of the rules. Ecological knowledge is learnt through observation, hands-on experience and storytelling. Younger Rakiura Maori now spend less time harvesting which puts pressure on the transmission of knowledge. Paradoxically, use of modern technology for harvesting aids transfer of essential skills because it is easier and faster to learn, thereby contributing to the continuance of a culturally important harvest. Limits on harvest are passive, with the numbers of chicks taken determined by the time spent harvesting and processing. Processing is more limiting during the rama period. Future innovations that decrease the time to process each chick during rama could greatly increase the total number of chicks caught. Recently introduced motorised plucking machines decrease the time required to pluck each chick. However, on Putauhinu Island, use of plucking machines did not increase the number of chicks harvested, indicating social mechanisms were also limiting. Elders identified changing values between the generations, which may reduce the future strength of social limitations on harvest pressure. Global climate change may reduce the predicability of traditional knowledge. Rakiura Maori have identified this risk and sought to examine ecological science as a tool to complement traditional knowledge for monitoring harvest sustainability. Climate change, declining tītī numbers and potential changes in technology or markets all threaten the effectiveness of current social limits to harvest. Rakiura Maori have previously shown the ability to adapt and must look to add resilience to their institutions to ensure we keep the titi forever.

Thesis (Ph. D.)--Murdoch University, 2002. / Includes bibliographical references (p. 311-323).

The sooty shearwater (also known as the muttonbird, Titi, Puffinus griseus) is a long-lived super-abundant, burrow nesting petrel, harvested by Rakiura Maori from breeding colonies, located in southern New Zealand. The harvest is culturally defining and enormously important for Rakiura Maori. The work in this thesis contributes to the Kia Mau te Titi Mo Ake Tonu Atu Research Project being undertaken by Rakiura Maori and the University of Otago, towards assessing ongoing sustainability of the harvest and future threats. Analyses of eight muttonbirder harvest records spanning, 1938 to 2004, show that harvest rates demonstrate, systematic commonalities in seasonal patterns and broad-scale consistency in trends of chick abundance and quality across harvested islands. If co-ordinated and well replicated, harvest records offer Rakiura Maori a low-cost and effective monitoring tool of sooty shearwater reproductive success and long-term population abundance. Hunt tallies provide additional evidence of a dramatic reduction in sooty shearwater abundance from the late 1980s that was also detected by counts from boats off the western seaboard of the USA. A conservative estimate of overall decline in hunt success across diaries, for the period 1972 to 2004, is 1.89 % (CI₉₅ 1.14 to 2.65) per annum, a total reduction of 39.2%. The harvesting records show a sooty shearwater mortality event occurred just prior to the 1993-breeding season at the same time as a severe negative anomaly in both the Pacific Decadal Oscillation and Southern Oscillation Indices. The hunting diaries show a decoupling of chick size with harvest success in the early 1990s. This resulted from a decline in harvest success and an increase in its variability, while chick size remained correlated with changing chick abundance and maintained its pre-1990 average. Long- lived seabirds maintain high survival by skipping breeding and abandoning breeding attempts when oceanic conditions deteriorate, increasing variability in chick abundance is also evidence of pressure on adult survivorship. The multiple diaries confirm these were major demographic events not confined to a single island. My survival estimates for The Snares and Whenua Hou were very high 0.952 (0.896-0.979) compared to earlier estimates for this species. Transience at the colonies is high due to the presence ofjuvenile and pre-breeding birds. Both naturally high survival and the large number of transient pre-breeders indicate sooty shearwater are more resilient to harvest than earlier survival models suggested. There was no evidence for directional change in sooty shearwater breeding phenology over 49-years of harvest. Climate fluctuation/change is therefore apparently not altering egg-laying. Peak fledging occurred fairly consistently in the 2nd of May (IQR = 2.91 days). Yearly variability in emergence occurs primarily due to provisioning and localized fledging conditions. Larger chick size was strongly correlated with delayed fledging and is consistent with the traditional ecological knowledge of the birders. There was no evidence for chicks becoming smaller or that years with starving chicks were more common, so increasing mismatch of breeding with optimal forage was not indicated. The past proportion of birders over the last 20 years (1985 - 2005) has been ~2% all of Rakiura Maori. Approximately 376 birders participated in the 2006 season with an estimated of overall harvest intensity 19.4% (CI₉₅ = 13.8 - 24.2%) and a total catch of 381,000 (CI₉₅ = 262,257 - 487,186) chicks. This study found evidence that catch rates reduced with increasing birder competition partially mitigating effects on harvest pressure. The combined effects of potential climate change on bird abundance and increased harvester competition suggests that the proportion of Rakiura Maori whom choose to bird is likely to decrease as tallies reduce and cost recovery becomes more difficult. Rakiura Maori have for many years cherished and maintained their islands and implemented protective measures to safeguarded titi breeding habitat. Future harvest management will have additional issues to contend with, but Rakiura Maori are necessarily confronting these issues as the titi culture rests on the maintenance of their taonga. The information presented in this thesis shows that combining science and traditional knowledge is a powerful tool for managing harvest sustainability.

The discovery and taxonomic history of fluttering shearwater (Puffinus gavia (Forster) and Hutton's shearwater (Puffinus huttoni Mathews) are reviewed. Taxonomic theory, where appropriate to this thesis, is discussed. The external morphology of P. gavia and P. huttoni is compared. No single external measurement or plumage character separates more than 60% of birds examined. The best system of identification is to compare the ratio of different body parts within an individual bird. The distribution of P. gavia and P. huttoni is compared. Hutton's shearwater feeds further out to sea and it is believed to be a migrant species wintering in north west Australian waters. The fluttering shearwater is believed to be a semi-migrant species with only the juveniles spending time in south east Australia. The red cell enzymes of P. gavia, P. huttoni and P. griseus are compared. There are differences in two esterase loci between gavia and huttoni, while P. griseus is more distantly related. Nei's genetic identity values are calculated. The systematic value of electrophoretic data is discussed. The relationship of an undescribed subfossil shearwater to P. gavia and P. huttoni is discussed. An outgroup analysis to other shearwater species is carried out according to phylogenetic (cladistic) theory. The subfossil shearwater is most closely related to the fluttering shearwater, and these two form a sister group to Hutton's shearwater. These three species are a sister group of P. opisthomelas. The relationship between the many P. assimilis subspecies, the black-backed Manx shearwaters, and the gavia, huttoni and opisthomelas group was not resolved. Puffinus nativitatis is more closely related to the Manx and the little shearwaters than to the P. griseus, P. tenuirostris group.

[Truncated abstract] Ecosystem engineers are organisms that physically modify habitat in a manner that modulate resource flows and species within ecosystems. Ecosystem engineering is distinct from classical interactions (competition, predation, parasitism and mutualism) in that it does not involve direct trophic exchange between organisms. The term ‘ecosystem engineer’ is a recently adopted one, and we are just beginning to investigate the occurrence and impact of engineers in ecosystems. My thesis explores the ecosystem engineering actions of Wedge-tailed Shearwaters, Puffinus pacificus, in a Mediterranean island, heathland ecosystem. I have approached this by (1) describing and quantifying the physical impact of these engineers, and (2) describing and quantifying the effects that these actions have on three major ecosystem components: the soil, the vascular plants, and the vertebrate fauna. Wedge-tailed Shearwaters are procellariid seabirds that excavate nesting burrows on offshore islands. The birds are colonial nesters, and on Rottnest Island, 17 km off the mainland coast of south-western Western Australia, their colonies have expanded considerably in recent decades. The expansion fits the trend observed in other tropicalorigin seabirds that breed in south-western Australia. In the last ten years, two new colonies have appeared (in a total of six) and the number of burrows on the island has almost doubled, to 11 745 ± 1320SE. In the same period the area occupied by the birds has increased by almost half ...

Dans l’optique de la gestion de population du puffin d’Audubon de Martinique, cette thèse a permis d’établir un diagnostic démographique et d’apporter des connaissances indispensables sur l’écologie marine de cette espèce. La population a connu une croissance assez marquée les dernières années, correspondant à une période où les rats ont été exterminés et le suivi de la colonie réduit pour limiter le dérangement. Cependant, le principal facteur ayant expliqué cette augmentation de la population, a été une amélioration des conditions marines favorisant une disponibilité des proies plus importante, particulièrement hors reproduction. L’augmentation de la survie des adultes a été alors expliquée en grande partie par un effet positif des variations de température d’eau de surface de l’océan (SST) hors reproduction et un effet positif du débit de l’Amazone avec un décalage d’un an. En mer, on remarque que le puffin d’Audubon de Martinique a un comportement sédentaire avec une distribution très régionale limitée aux Petites Antilles et proche des côtes du nord de l’Amérique du Sud. Sa niche alimentaire est sous la forte influence d’apports fluviaux de l’Amazone et de l’Orénoque, milieux à faible salinité et à SST élevée. De plus, les zones d’alimentation de la population de Martinique diffèrent de celle de Bahamas et cela suggère une double problématique de gestion de la sous-espèce de la Caraïbe. Ces nouvelles connaissances permettront de mieux orienter les mesures de conservation mais soulignent également le besoin de clarifier la taxonomie de cette espèce à l’échelle de la Caraïbe, la dynamique de la population et d’évaluer plus précisément les menaces en mer. / In the context of management of Audubon’s shearwater population from Martinique, this thesis has established a demographic diagnosis and provided essential knowledge on the marine ecology of this species. The population has experienced a fairly marked growth in recent years, corresponding to a period where the rats were exterminated and monitoring of colony was limited to reduce the disturbance. However, the main factor that explained the increase in population was improved marine conditions favoring greater availability of prey, especially outside reproduction. The increase in adult survival was then explained in large part by a positive effect of changes in ocean surface water temperature (SST) out of reproduction and a positive effect of the flow of the Amazon with a lag one year. At sea, we notice that the puffin Audubon Martinique has sedentary behavior with very limited regional distribution and the Lesser Antilles near the northern coast of South America. Its food niche is under the strong influence of riverine inputs of the Amazon and Orinoco, low salinity and high SST environments. In addition, foraging areas of Audubon's Shearwater from Martinique differ from that of the Bahamas and this suggests a double subspecies of the Caribbean management problematic. This new knowledge will help guide conservation measures but also underline the need to clarify the taxonomy of this species throughout the Caribbean, the dynamics of the population and to more accurately assess its threats at sea.