Diet of common diving-petrels (Pelecanoides Urinatrix Urinatrix) in Southeastern Australia during chick rearing

Unlike conspecifics in the subantarctic region, which typically begin breeding in mid-spring to summer, Common Diving-petrels Pelecanoides urinatrix urinatrix in southeastern Australia (towards the northern limit of the species\u27 distribution) commence breeding mid winter. Knowledge of the foraging ecology of this species is crucial to understanding the factors that influence its timing of breeding in the region, yet there is currently little information available. Analysis of 43 stomachs of breeding adults, collected opportunistically after they were killed in a fire which burned through their colony, indicated that their diet was dominated by two taxa: a euphausiid Nyctiphanes australis which comprised 87% of the diet by number; and a hyperiid amphipod Themisto australis which constituted a further 12.5%. Mean lengths (&plusmn;SE) of N. australis (n = 39) and T. australis (n = 41) were 12 mm (&plusmn;0.3) and 5.2 mm (&plusmn;0.2), respectively. The importance of N. australis in the diet of Common Diving-petrels is discussed in relation to their timing of breeding and the euphausiid\u27s potential role in the Bass Strait pelagic ecosystem.<br /

Timing of breeding and diet of the Black-faced cormorant Phalacrocorax fuscescens

Previous anecdotal reports have suggested that Black-faced Cormorant Phalacrocorax fuscescens breeds only in winter in southeastern Australia, but detailed reports confirming this are lacking. Here we examine the timing of breeding in Black-faced Cormorants at Notch Island in northern Bass Strait in 2006. Peak laying occurred during winter (ca 26 July). The diet of Black-faced Cormorants was predominantly fish (97% of identified prey) and varied between breeding and post-breeding periods. Black-faced Cormorants consumed a total of 14 different species with four species having a frequency of occurrence in the diet of ?5% during the breeding season and six species during the post-breeding period. We provide data for the first time on the chronology of breeding of Black-faced Cormorants in one year and give a preliminary description of their diet based on pellet analyses. We propose that late winter breeding may be a strategy to avoid the high ambient temperatures in northern Bass Strait during summer, the associated higher thermoregulatory costs for adults and the increased mortality for chicks

Balance: a neglected factor when attaching external devices to penguins

We observed that external attachments on penguins reduced their balance, which may be of as great concern to the individuals as the effect of increased drag. Little penguin Eudyptula minor swimming activity was observed in captivity at the Penguin Parade (r), Phillip Island, Australia. Initially, time-depth recorders (TDRs) were attached centrally to the lower back of the penguins, the point for attachment widely suggested in the literature. In the water, the penguins showed strong signs of imbalance. They tilted from side to side trying to maintain stability, avoided diving and did not move around the pool. When the TDRs were moved forward, closer to the penguins\u27 centre of gravity, the penguins started diving, swimming and preening as they had before having the TDRs attached. These observations suggest that the lower back area may not be the best attachment position for little penguins and that balance could be an important factor to consider when using back-mounted devices

Assemblage, size and abundance bias in a novel sandy shore macro-infaunal sampling technique

Sampling sandy shore macro-invertebrate fauna is critical in enhancing our understanding of beach ecology and conservation, and is a common monitoring approach. The traditional, and almost universal, method of sampling involves sieving sand to locate infauna, but here we describe a novel Hydraulic Sampling Device (HSD), a candidate method for future macro-invertebrate sampling, which has the potential to be faster and more effective at sampling invertebrates. We compared the results obtained by these two methods. Macro-invertebrate fauna of six beaches on Phillip Island, southern Victoria, Australia were sampled in the upper and lower beach. On average, the HSD sampled a smaller size range of fauna than the sieving method, perhaps because of longer handling times and escape of larger individuals. The sieving method found more individuals and a higher species richness. The methods we describe do not produce directly comparable results. On balance, the sieving method is simpler, apparently not as prone to &lsquo;escape bias&rsquo;, and reports higher abundances and richness of beach infauna

Waddling on the Dark Side: Ambient Light Affects Attendance Behavior of Little Penguins

Visible light on Earth largely comes from the sun, including light reflected from the moon. Predation risk is strongly determined by light conditions, and some animals are nocturnal to reduce predation. Artificial lights and its consequent light pollution may disrupt this natural behavior. Here, we used 13 years of attendance data to study the effects of sun, moon, and artificial light on the attendance pattern of a nocturnal seabird, the little penguin Eudyptula minor at Phillip Island, Australia. The little penguin is the smallest and the only penguin species whose activity on land is strictly nocturnal. Automated monitoring systems recorded individually marked penguins every time they arrived (after sunset) at or departed (before sunrise) from 2 colonies under different lighting conditions: natural night skylight and artificial lights (around 3 lux) used to enhance penguin viewing for ecotourism around sunset. Sunlight had a strong effect on attendance as penguins arrived on average around 81 min after sunset and departed around 92 min before sunrise. The effect of moonlight was also strong, varying according to moon phase. Fewer penguins came ashore during full moon nights. Moon phase effect was stronger on departure than arrival times. Thus, during nights between full moon and last quarter, arrival times (after sunset) were delayed, even though moonlight levels were low, while departure times (before sunrise) were earlier, coinciding with high moonlight levels. Cyclic patterns of moon effect were slightly out of phase but significantly between 2 colonies, which could be due to site-specific differences or presence/absence of artificial lights. Moonlight could be overridden by artificial light at our artificially lit colony, but the similar amplitude of attendance patterns between colonies suggests that artificial light did not mask the moonlight effect. Further research is indeed necessary to understand how seabirds respond to the increasing artificial night light levels.Peer reviewe

A novel spatio-temporal scale based on ocean currents unravels environmental drivers of reproductive timing in a marine predator

Life-history strategies have evolved in response to predictable patterns of environmental features. In practice, linking life-history strategies and changes in environmental conditions requires comparable space–time scales between both processes, a difficult match in most marine system studies. We propose a novel spatio-temporal and dynamic scale to explore marine productivity patterns probably driving reproductive timing in the inshore little penguin (Eudyptula minor), based on monthly data on ocean circulation in the Southern Ocean, Australia. In contrast to what occurred when considering any other fixed scales, little penguin's highly variable laying date always occurred within the annual peak of ocean productivity that emerged from our newly defined dynamic scale. Additionally, local sea surface temperature seems to have triggered the onset of reproduction, acting as an environmental cue informing on marine productivity patterns at our dynamic scale. Chlorophyll-a patterns extracted from this scale revealed that environment factors in marine ecosystems affecting breeding decisions are related to a much wider region than foraging areas that are commonly used in current studies investigating the link between animals' life history and their environment. We suggest that marine productivity patterns may be more predictable than previously thought when environmental and biological data are examined at appropriate scales.Peer reviewe