The breeding success of the Little Penguin was significantly higher in northern populations compared with documented southern colonies. Several southern colonies including Phillip Island in Victoria and colonies in Tasmania, have been characterised by poor breeding success, increasingly later commencement of breeding, and declining populations. This study aimed to compare and contrast the ecological attributes of a thriving northern population with other documented colonies. I collected long term data on breeding success (1987 to 1997) of the Little Penguin on Bowen Island, and related variability in breeding success to ocean currents and climate patterns, foraging behaviour and diet, nesting habitat, and inter-specific and fisheries competition. The benefits of successional changes to nesting habitat on Bowen Island since active habitat management commenced in 1989 were examined, including the importance of burrow depth, aspect, distance to water from the burrow, and vegetation type on breeding success of the Little Penguin. Morphological measurements of east coast penguins indicated a north-south cline, similar to that described in New Zealand. The Little Penguin was larger at higher latitudes. Whilst adults were sedentary and displayed a high degree of nest site fidelity, juveniles dispersed widely in their first three years, but then returned to the colony, sometimes to their natal burrow, to breed. This appears to be an adaptive mechanism, which selects for high quality nesting habitat. The study confirmed earlier findings that mature vegetation assemblages, namely woodland and forest, support higher breeding success than structurally simpler grassland and herbland habitat. This may contribute to observed differences in breeding success between northern and southern colonies, because many of the southern colonies have degraded nesting habitat. Most important to the diet of the Little Penguin were clupeoids, which dominated the fish species of Jervis Bay. The substantial clupeoid resources were targeted by the tuna fishery for bait, in the same areas and coinciding with maximum demands (chick raising and fledging), as penguins. The potential quantity of baitfish taken from Jervis Bay was over 10, 000 tonnes per year, which was well beyond the quantities raising concerns in other regions, although the fishery remains unregulated. Nevertheless, the foraging range of Bowen Island penguins was smaller than has previously been described Little Penguins on Bowen Island had a heavy reliance on relatively shallow waters of the Bay, within 5 km of the island. Daily foraging distances exceeding 20 km coincided with low breeding success, sometimes below that required for population replacement. Greater daily foraging range during the breeding season in southern Victoria may explain in part why these populations are declining. The principal mechanism for nutrient enrichment of Jervis Bay waters was the East Australia Current (EAC). This is a large and powerful, warm water boundary current of 250 km diameter and 1000 feet depth, which promoted slope water intrusion through upwelling along the New South Wales coast during the study, particularly during the penguin breeding season. The EAC effects northern colonies, but less so southern colonies. The Bowen Island colony was prone to periodic breeding failure, which was related to the El Nino Southern Oscillation (ENSO) phenomenon, indicated in Australia by the Southern Oscillation Index (SOI). ENSO warm events, corresponding with negative values of the SOI, depressed the EAC and caused downwelling, leading in some seasons to increased breeding failure. There was a correlation between both fledging success and adult mortality, and the SOI. The mean breeding success of the Bowen Island colony, at 1.46 chicks per pair over the ten-year study, was the highest recorded for the Little Penguin, and the population was increasing.

This thesis analyses yearly mark-recapture-recovery information collected over a 36- year period, from 1968 to 2003, for 23 686 flipper-banded Little Penguins Eudyptula minor of Phillip Island, in south-eastern Australia. Such a long-term data set is extremely rare for any species. Few studies of any animal have been able to model age dependence for the survival, recapture and recovery probabilities simultaneously. I successfully apply such a modelling scheme and obtain biologically realistic age structures for the parameters. I also provide illustrations of erroneous results that may arise when analyses fail to consider simultaneous age dependence, or fail to detect annual variations that may mask age dependence. I obtain a low survival estimate of 17% in the first year of life, increasing to 71% in the second year, and around 80% thereafter, and declining gradually after age nine years. First-year survival increases with number of chicks fledged per pair, increases with annual average fledging weight and decreases with mean laying date. An increase in first-year survival is associated with warmer sea surface temperatures in the summer and autumn of the previous year, which agrees with biological considerations. Irrespective of this inter-year variation, birds born early in the breeding season, relative to the rest of their cohort, have greatly enhanced first-year survival, when compared to birds born late in that season. Fledglings survive better in years in which the mean fledgling weight is higher, and fledglings of above average weight have a better chance of survival than their underweight counterparts. I next analyse seven years of recapture data from a separate experiment studying the effect of banding on adult Little Penguins. In the year following marking, the i survival probability of banded birds is 6% lower than that of unbanded birds, while in subsequent years the survival is 4% lower for banded birds. Band loss is negligible. Finally, I compare the survival estimates for Phillip Island with those obtained for a six-year study in New Zealand. While first-year survival is significantly higher for New Zealand, there is a marked decline over time, coinciding with an increase in population size.

The Blue Penguin (Eudyptula minor) is assumed to be declining over much of its range, largely due to introduced predators. Anecdotal evidence suggests that one of the areas of declining population is the West Coast of the South Island. The purpose of this study was to determine the reasons for the assumed decline of blue penguins in South Westland. This was done by studying breeding ecology at several blue penguin colonies to assess the importance of breeding success and adult mortality on the penguin population. Three blue penguin colonies in South Westland, at Five Mile and Three Mile beaches south of Okarito, and at the Wanganui River mouth near Harihari, were monitored throughout the 2008/09 breeding season. During each burrow visit the number of eggs and chicks were recorded as well as the date of laying, hatching or fledging. Five colonies of blue penguin were also monitored in Buller over the same breeding season in a study conducted by the West Coast Blue Penguin Trust, a community trust based on the West Coast. The results of both studies were compared to determine the effect of predator control on breeding parameters, such as breeding success. Of 137 eggs laid in South Westland, 108 chicks survived until fledging, giving an overall breeding success of 78.8%. In Buller, 64 chicks survived to fledging from 101 eggs laid, resulting in an overall breeding success of 63.4%. Breeding success was significantly higher at penguin colonies in South Westland, compared to the Buller colonies. There was no evidence that predator control had an effect on breeding success in South Westland or Buller. The mean number of chicks fledged per pair that produced eggs was 1.55 in South Westland and 1.16 in Buller. The overall proportion of occupied breeding burrows compared to the total number of suitable burrows at the South Westland sites was 73.8% (n = 103). At the Buller sites, only 60.3 % (n = 151) of the total number of burrows was occupied. Road kills are a major threat to blue penguins in Buller due to the proximity of colonies to the state highway. Fortunately, incidences of road death in South Westland are rare and due to the distance from roads, do not pose a significant threat to South Westland blue penguins. Further study of blue penguin colonies in South Westland is needed to learn more about annual variation in breeding productivity and to determine if breeding success is consistently high over an extended time period. If this is the case, then the cause of blue penguin decline on the West Coast is unlikely to be due to problems with breeding as the breeding success during this study is one of the highest recorded for blue penguins. Although there was no apparent effect of predator control on breeding productivity during this study there is evidence from other locations that predators, in particular stoats, have contributed to the decline of blue penguin populations. More research into the impact of predators on penguins over a longer period of time is needed on the West Coast before a change is made to how predators are managed.