Many challenges still exist in the empirical measurement of population size or density of burrow-nesting procellariiforms. Although reasonable precision of burrow occupancy estimates can be achieved with 10-15 transect (20 entrances per transect) per site, unknown levels of bias in burrow occupancy estimates currently prevents reliable estimation of burrow-nesting procellariiform abundance or harvest rates. Because it is unlikely that biases in burrow occupancy are similar among colonies, valid comparisons among sites may require estimates of absolute abundance rather than relative measures of burrow occupancy. The reliability and precision of matrix models for procellariids will depend primarily on the reliability and precision of adult survival estimates. Sensitivities, elasticities and uncertainties of population growth rate to demographic parameters for models with differing structures and parameterisations showed an overwhelming importance of adult survival in determining population growth rate and results of perturbation analyses. Estimates of adult survival should be a primary focus of any procellariid research program involving assessment of population status, or questions of population response to perturbations. Juvenile survival, pre-breeder survival and emigration rates were also shown to be relatively important in determining population growth rate and perturbation analyses. The sensitivity and elasticity of population growth rate to survival rates for all immature stages combined were similar in magnitude to the sensitivity and elasticity of population growth rate to survival rates for fecund birds. Estimation of survival rates for immature birds should also be given high priority in procellariid research programs. The variability in these parameters among populations needs to be assessed if results are to be generalised beyound specific colonies from which parameters are estimated. There is evidence that selective harvest of heavier Titi chicks occurs on at least some islands. However, analyses of a demographic model incorporating different quality chicks showed even extremely high degrees of selective harvest had little influence on population growth rate or perturbation analyses unless overall harvest levels were very high. Comparison of population growth rate and perturbation analyses of models differing in the level of detail in parameterisation or in the number of stages included in the model, showed negligible differences in results. This suggests that simple models, even if based on only sparse data, are adequate to set research priorities and evaluate population response to perturbations such as for the assessment of conservation management options, evaluation of possible causes of population change and assessment of the effects of harvest.

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.