Penguin Eggs Research Articles

Penguin's Egg by Anna Kemp (review)

Penguin's Egg by Anna Kemp (review)

Diet and Feeding Behavior of the South Polar Skuas Stercorarius maccormicki in the Haswell Islands, East Antarctica

The diet and feeding behavior of South Polar Skuas (Stercorarius maccormicki) are well studied within the species’ breeding range but are poorly understood on the Haswell Islands. The aim of this study was to determine how South Polar Skuas use available resources during the pre-breeding and breeding periods at the Haswell Archipelago (66°31′ S, 93°01′ E, Davis Sea, Southern Ocean) under conditions of prolonged human activity. I studied pellets, spontaneous regurgitation, and stomach contents of feathered birds to study the diet of skuas and used direct observations of their feeding behavior. South Polar Skuas at the Haswell Islands fed primarily on the Emperor Penguin (Aptenodytes forsteri) colony and on terrestrial resources in the Adélie Penguin (Pygoscelis adeliae) and fulmarine petrel colonies. The dominant prey of skuas were breeding Antarctic penguins. Emperor Penguins and Adélie Penguins make up the bulk of the skuas’ diet in the pre-breeding and breeding periods. Surface feeding at sea was observed in the post-breeding period. In recent decades, kitchen waste supported the skua population. Scavenging (placenta and feces of Weddell seals [Leptonychotes weddellii], frozen eggs, chicks and adults of breeding bird species, kitchen refuse) is the dominant strategy for obtaining food. Adélie Penguin eggs and chicks were the main food items of the South Polar Skuas in the Haswell Archipelago. Skua predation could potentially influence the breeding success of Adélie Penguins and fulmarine petrels, but the extent of the impact is unknown. The impact of the South Polar Skua on Emperor Penguins is negligible because skuas feed mainly on frozen chicks and eggs of the species.

Evaluation of Metal Partitioning across Humboldt Penguin (Spheniscus humboldti) Egg Components.

Humboldt Penguin (Spheniscus humboldti) population declines are attributable to several multifaceted anthropogenic impacts. At present, the exposure of Humboldt Penguins to high concentrations of heavy metals in the marine environment is a preeminent concern, due to mining along the Peruvian coast near key rookery sites. Metal and selenium concentrations were determined in eggs collected from September 2020 to April 2021 from a managed-care penguin population at the Brookfield Zoo to establish reference values for health indices conducted on wild populations. Concentrations of 16 elements, with emphasis on those found in mine efflux-arsenic, cadmium, copper, lead, mercury, selenium, and zinc-were assessed via inductively coupled plasma mass spectrometry in yolk, albumen, and eggshell. Data analyses indicate a clear delineation between egg constituents, with lipid-rich yolk displaying notably higher concentrations (μg/g) of arsenic (0.20 ± 0.064), chromium (0.086 ± 0.03), cobalt (0.01 ± 0.003), iron (238.65 ± 54.72), lead (0.32 ± 0.97), manganese (2.71 ± 0.66), molybdenum (0.57 ± 0.14), tin (3.29 ± 0.99), and zinc (64.03 ± 13.01) than other components (albumen and eggshell). These data confirm that heavy metals are partitioned differently across Humboldt Penguin egg components, which provides insight into the potential connection between embryonic nutrient source contamination and subsequent chick viability.

Assessment of the Safety and Efficacy of an Oral Probiotic-Based Vaccine Against Aspergillus Infection in Captive-Bred Humboldt Penguins (Spheniscus humboldti).

Aspergillosis is a fungal infection caused mainly by Aspergillus fumigatus that often results in respiratory disease in birds. Aspergillosis is a major cause of morbidity and mortality in captive-bred penguin species. Currently, there is no registered vaccine to prevent aspergillosis. Recent research demonstrated that oral administration of gram-negative bacteria expressing high levels of galactose-α-1,3-galactose (α-Gal) modulates anti-α-Gal immunity and protects turkeys from clinical aspergillosis caused by experimental A. fumigatus infection. The role of anti-α-Gal immunity in penguins has not been studied. Here, we tested the distribution of α-1,3-galactosyltransferase (α1,3GT) genes in the fecal microbiome of Humboldt penguins (Spheniscus humboldti). The occurrence of natural anti-α-Gal antibodies (Abs) in sera and eggs of healthy Humboldt penguins was also assessed. A trial was then conducted to test whether oral administration of Escherichia coli Nissle, expressing high α-Gal levels, modulates anti-α-Gal immunity in a colony of Humboldt penguins. Animals in the vaccination and placebo groups were evaluated before the trial and followed for one year for aspergillosis detection using a diagnostic panel including computed tomography scans, capillary zone electrophoresis, 3-hydroxybutyrate levels, and anti-A. fumigatus Abs. Anti-α-Gal Abs were detected in sera (IgM and IgY) and eggs (IgY) of healthy penguins. Microbiota analysis and functional predictions revealed the presence of α1,3GT genes in the microbiota of Humboldt penguins and other penguin species. A strong decrease in anti-α-Gal IgM levels was observed in all animals in the placebo group three months after vaccination protocol. This decrease was not observed in E. coli Nissle-treated penguins. After the vaccination protocol, we found a positive correlation between anti-E. coli IgY and anti-α-Gal IgY in the E. coli Nissle group, suggesting a correlation between the presence of the bacteria and these Abs. During the study period, three penguins exhibited respiratory signs consistent with aspergillosis. Two were from the placebo group whose symptoms resolved with specific treatments, while a single vaccinated individual developed fatal respiratory aspergillosis eight months after the trial. We conclude that E. coli Nissle represents a safe potential probiotic with a protective effect against aspergillosis in Humboldt penguins that deserves to be further explored for therapeutic uses in these animals.

Intraspecific Variation in Mercury, δ15 N, and δ13 C Among 3 Adélie Penguin (Pygoscelis adeliae) Populations in the Northern Antarctic Peninsula Region.

Mercury (Hg) is a pervasive environmental contaminant that accumulates in the organs and tissues of seabirds at concentrations capable of causing acute or long-term adverse health effects. In the present study, Hg concentrations in Adélie penguin (Pygoscelis adeliae) egg membranes and chick feathers served as a proxy for Hg bioavailability in the marine environment surrounding the northern Antarctic Peninsula. Stable isotopes were measured in conjunction with Hg to infer information regarding feeding habits (δ15 N, diet/trophic level; δ13 C, foraging habitat). The Hg concentrations were low relative to toxicity benchmark values associated with adverse health effects in birds and ranged between 0.006 and 0.080 µg g-1 dry weight (n = 65) in egg membranes and 0.140 to 1.05 µg g-1 fresh weight (n = 38) in feathers. Egg membrane δ15 N signatures suggested that females from different breeding colonies had similar diets consisting of lower and higher trophic prey prior to arrival to breeding grounds. In contrast, δ15 N signatures in feathers indicated that chick diet varied by colony. The Hg concentrations demonstrated significant positive relationships with δ15 N, providing support for the hypothesis of Hg biomagnification up the food chain. The δ13 C signatures in both tissue types provided evidence of foraging habitat segregation among populations. The differences in Hg exposure and foraging ecology suggest that each colony has localized foraging behaviors by breeding adults that warrant additional investigation.Environ Toxicol Chem 2021;40:2791-2801. © 2021 SETAC.

Evaluation of PCDD/Fs, PCBs and PBDEs in two penguin species from Antarctica

Persistent Organic Pollutants (POPs) are a global threat, but impacts of these chemicals upon remote areas such as Antarctica remain unclear. Penguins can be useful species to assess the occurrence of POPs in Antarctic food webs. This work's aim was the evaluation of polychlorodibenzo-p-dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in eggs of two penguin species, chinstrap (Pygoscelis antarticus) and gentoo penguins (Pygoscelis papua), breeding in the South Shetland Islands. Results showed a common pattern in POP levels regardless of the species, characterized by a major abundance of PCBs (98 %), followed by PBDEs (1–2%) and PCDD/Fs (<1 %). Concentrations of POPs in chinstrap and gentoo penguin eggs were 482 and 3250 pg/g l.w., respectively. PCBs, PBDEs and PCDD/Fs were found at higher concentrations in chinstrap penguin eggs, being these differences significant for PBDEs. Interspecies differences in POP levels agree well with potential trophic position differences among species due to changes in prey composition and foraging areas. POP profiles were dominated by congeners with a low degree of halogenation. Our results therefore suggest similar sources of POPs in the food webs exploited by both species and in both cases attributable to the long-range transportation rather than to the presence of local sources of POPs. TEQs were found between 1.38 and 7.33 pg/g l.w. and followed the pattern non-ortho dl-PCBs > PCDFs > PCDDs > mono-ortho dl-PCBs. TEQ values were lower than the threshold level for harmful effects in birds of 210 pg/g WHO-TEQ/g l.w.

Technological advances in stable isotope analysis provide ever more insights into animal ecology.

In Focus: Whiteman J. P., Newsome S. D., Bustamante P., Cherel Y., Hobson K. A. (2021). Quantifying capital versus income breeding: New promise with stable isotope measurements of individual amino acids. Journal of Animal Ecology, 90, 1408-1418. The use of bulk stable isotope analysis (SIA) has become a staple in the field of ecology since the 1980s. This approach has proven its utility, but comes with limitations rooted in assumptions and confounding factors. Compound-specific SIA (CS-SIA) has the potential to address questions out of reach of bulk SIA by providing information on physiological pathways as well as dietary sources of consumer isotopes. Whiteman et al. (2021) provide an excellent example of the power of CS-SIA using amino acid stable isotopes to quantify the extent of capital versus income breeding involved in emperor penguin egg production. By doing so, they reframe an important life-history trait as a spectrum, rather than a dichotomy. This showcases the use of CS-SIA as a tool for investigating the resource allocation strategies employed by this species, and the potential for this technique to untangle the life-history strategies of a broad range of species.

Transmission of a novel predatory behaviour is not restricted to kin

Corvids are exceptional predators which can become problematic and difficult to manage due to their adaptability, intelligence, and abundance. On Phillip Island (Victoria, Australia) little ravens (Corvus mellori) prey on the eggs of burrow-nesting little penguins (Eudyptula minor) at an ecologically and economically significant colony. Raven depredation of penguin clutches is intense but appears to have emerged only in recent years. Understanding whether or how the behaviour is transferred provides an opportunity to disrupt this undesirable behaviour. We explore the role genetic relatedness may have on the occurrence of raven burrow-raiding behaviour. We test an hypothesis regarding one specific scenario of possible transmission, namely that ravens preying upon eggs/young in penguin nests share genetic traits that facilitate burrow raiding, and are therefore more genetically related than birds which do not raid burrows. Using 15 microsatellite loci, we found no significant difference in mean relatedness between culprits and other birds. Burrow-raiding behaviour does not appear to be restricted to kin, and targeting ravens based solely on their relationship to culprits is unlikely to reduce depredation rates. However, targeting known culprits may slow transmission of burrow-raiding behaviour.

Restoration of two great auk (Pinguinus impennis) eggs: Bourman Labrey's egg and the Scarborough egg

Most of the approximately 75 known eggs of the extinct great auk ( Pinguinus impennis) are in public museums, with a few in private collections. A small number of these eggs has sustained damage, either at the time of collection or subsequently, and two of these eggs are known to have been repaired. The two eggs suffered rather different types of damage and were subsequently restored using different techniques. The first, known as Bourman Labrey's egg, sustained extensive damage sometime prior to the 1840s, when the shell was broken into numerous pieces. This egg was repaired by William Yarrell in the 1840s, and when it was restored again in 2018, it was discovered that Yarrell's restoration had involved the use of an elaborate cardboard armature. This egg is currently in a private collection. The second egg, known as the Scarborough egg, bequeathed to the Scarborough Museum in 1877, was damaged (by unknown causes) and repaired, probably by the then curator at Scarborough, W. J. Clarke, in 1906. This egg was damaged when one or more pieces were broken adjacent to the blowhole at the narrow end (where there was some pre-existing damage). The media reports at the time exaggerated the extent of the damage, suggesting that the egg was broken almost in two. Possible reasons for this exaggeration are discussed. Recent examination using a black light and ultraviolet (UV) revealed that the eggshell had once borne the words, “a Penguin's Egg”, that were subsequently removed by scraping.

From incubation to release: Hand-rearing as a tool for the conservation of the endangered African penguin.

The African penguin (Spheniscus demersus) population is estimated at 25,000 breeding pairs, approximately 5% of that at the start of the 20th century, and the species is currently classified as Endangered. In the last two decades, the hand-rearing of penguin chicks that were abandoned by their parents due to oil spills or other circumstances has become a valuable conservation tool to limit mortality and to bolster the population at specific colonies. We summarize and evaluate the techniques employed by the Southern African Foundation for the Conservation of Coastal Birds (SANCCOB) to incubate and hand-rear African penguin eggs and chicks. From 2012 to 2016, a total of 694 eggs and 2819 chicks were received by SANCCOB’s Chick Rearing Unit. It was estimated that 13% of the eggs were infertile, and 81% of the fertile eggs hatched successfully. The overall release rate for chicks was 77%, with a higher release rate for chicks that were pre-emptively removed (93%) followed by chicks that had been abandoned by their parents (78%), chicks admitted due to avian pox lesions (61%), chicks that hatched from artificially-incubated eggs (57%), and chicks admitted due to injuries or deformities (25%). Rescuing and hand-rearing eggs and chicks has been a successful strategy for African penguins, and might be also applicable for the conservation of other threatened seabird species whose population are critically low or during natural or anthropogenic events that could have disastrous population impacts (e.g. oil spills, disease outbreaks, catastrophic weather events, strong El Niño years, etc.).

A 50-year retrospective of persistent organic pollutants in the fat and eggs of penguins of the Southern Ocean

Persistent organic pollutants (POPs) such as dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), and polychlorinated biphenyls (PCBs) have been spreading to Antarctica for over half a century. Penguins are effective indicators of pelagic concentrations of POPs. We synthesized the literature on penguins to assess temporal trends of pelagic contamination in Antarctica, using fat and eggs to monitor changes from 1964 to 2011. DDT/DDE ratios suggest long-range atmospheric transport. Average DDT in fat (ww) increased from 44 ng g−1 in the 1960s, peaked at 171 ng g−1 in the mid-1980s, and then declined slowly to the present level of 101 ng g−1. Temporal trends in HCB contamination rose into the 1990s before declining. ∑HCHs in fat was ∼5 ng g−1 from 1960 to 1979, peaking at 33 ng g−1 during the period 1980–1989 before declining to ∼5 ng g−1 from 1990 to present. PCBs rose substantially from 1970 to 2009 in fat, varying more than DDTs and HCB in both fat and eggs. Antarctic penguins are good biological indicators of global DDT and HCB emissions, but the existing data are insufficient regarding HCHs and PCBs.

Organohalogenated contaminants in plasma and eggs of rockhopper penguins: Does vitellogenin affect maternal transfer?

Although many studies have investigated organohalogenated contaminants (OHCs) in yolk, little is known about the mechanisms and timing of transfer of OHCs from the female to the egg. Vitellogenin, a yolk precursor, has been suggested to play a role in this transport.We here report for the first time the temporal changes in OHC and an index of vitellogenin concentrations in female plasma from the pre-laying period to clutch completion in free-living birds: the southern rockhopper penguin (Eudyptes chrysocome chrysocome) breeding in the Falkland/Malvinas Islands. In addition, OHC concentrations in the corresponding clutches were analysed. OHC concentrations in female plasma and in the yolk of both the first (A-) and the second (B-)eggs followed a similar pattern, with hexachlorobenzene (HCB) > Σpolychlorinated biphenyls (PCBs) > Σdichlorodiphenyltrichloroethanes (DDTs) > Σmethoxylated polybrominated diphenyl ethers (MeO-PBDEs) > Σchlordanes (CHLs) > Σpolybrominated diphenyl ethers (PBDEs) ≈ Σhexachlorocyclohexanes (HCHs). The higher concentrations of MeO-PBDEs compared to PBDEs indicate a diet containing naturally-produced MeO-PBDEs. All OHC compounds except for PBDEs increased from the pre-laying period to A-egg laying and subsequently declined from A-egg laying to B-egg laying, and female plasma vitellogenin showed the same pattern. For ΣPCBs and ΣMeO-PBDEs, we found positive correlations between female plasma during A-egg laying and both eggs, and for HCB between female plasma and A-eggs only. During pre-laying, only ΣMeO-PBDEs correlated between both eggs and female plasma, and no correlations between OHC concentrations in eggs and female plasma were found during B-egg laying, highlighting that maternal transfer of OHCs is time- and compound-specific. Finally, female vitellogenin concentrations did not significantly correlate with any OHC compounds in either female plasma or eggs, and our results therefore did not confirm the suggested role of vitellogenin in the maternal transfer of OHC molecules into their eggs.

Using measurements to predict laying order in harvested Northern Rockhopper Penguin (Eudyptes moseleyi) eggs

The sustainable and responsible exploitation of natural populations for subsistence requires a scientific basis for management. Eggs of the Endangered Northern Rockhopper Penguin (Eudyptes moseleyi) in the Tristan da Cunha archipelago have been harvested since the 19th century with no restrictions on which (A- or B-eggs) can be harvested, despite the larger B-egg being much more likely to produce fledged offspring. Our objective was to create a discriminant function to predict the laying order of harvested eggs. We found that the discriminant function of D = 0.58 x Length + 0.39 x Breadth -57.48 successfully classified 91% of eggs as A- or B-eggs. When applied to previously collected harvest data, the discriminant function identified at least 36% of eggs as B-eggs. The method we describe here provides a mechanism around which one aspect of a management framework for the sustainable harvest of Northern Rockhopper Penguin eggs can be built.

Predation by New Zealand sea lions and Brown Skuas is causing the continued decline of an Eastern Rockhopper Penguin colony on Campbell Island

Identification of factors causing population declines is a critical prerequisite for conserving threatened species. The most likely cause of dramatic decreases in numbers of the ‘Vulnerable’ Southern Rockhopper Penguin (Eudyptes chrysocome) in the twentieth century is oceanographic change reducing food availability. For example, the massive decline of the Eastern sub-species (E. c. filholi) on Campbell Island, New Zealand (94.6 %, 1942–2012), has been attributed to climate change. This decline reversed in the mid-1990s after a shift to favourable conditions, but a localized decline continued at a small, fragmented population in Penguin Bay, where one of five sub-colonies went extinct in 2010, and the number of breeding pairs fell from 7360 in 1984 to 3012 in 2012. Emerging concerns for Eudyptes penguins are the effects of increased predation from native predators. At Campbell Island, monitoring demonstrated that penguin eggs and chicks in smaller sub-colonies were most vulnerable to predation by Brown Skuas (Catharacta antarctica lonnbergi), so that average reproductive success was 25 % lower at the smallest sub-colony than at the largest. ‘Endangered’ New Zealand sea lions (Phocarctos hookeri) were estimated to depredate 6 % of the adult penguin population each year, which modelling identified as the most important driver of the population’s negative exponential growth rate (λ = 0.905, −9.5 % per year). Although occasional years of very poor food availability may exert a larger ‘bottom–up’ effect on penguin demographic rates, the ‘top–down’ effects of high avian and pinniped predation rates can be sufficient to drive the decline of small penguin populations.

Relationship between legacy and emerging organic pollutants in Antarctic seabirds and their foraging ecology as shown by δ13C and δ15N

Foraging ecology and the marine regions exploited by Antarctic seabirds outside of breeding strongly influence their exposure to persistent organic pollutants (POPs). However, relationships between them are largely unknown, an important knowledge gap given that many species are capital breeders and POPs may be deleterious to seabirds. This study investigates the relationship between Antarctic seabird foraging ecology (measured by δ13C and δ15N) and POPs accumulated in their eggs prior to breeding. Organochlorinated pesticides, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and dechlorane plus (DP) were measured in eggs of chinstrap, Adélie, and gentoo penguins (Pygoscelis antarctica, P. adeliae, P. papua), as well as south polar skua (Catharacta maccormicki), sampled on King George Island. Total POP levels were as follows: skua (3210±3330ng/g lipid weight)>chinstrap (338±128ng/g)>Adélie (287±43.3ng/g)>gentoo (252±49.4ng/g). Trophic position and pre-breeding foraging sites were important in explaining POP accumulation patterns across species. The most recalcitrant compounds were preferentially accumulated in skuas, occupying one trophic level above penguins. In contrast, their Antarctic endemism, coupled with influence from cold condensation of pollutants, likely contributed to penguins exhibiting higher concentrations of more volatile compounds (e.g., hexachlorobenzene, PCB-28 and −52) than skuas. Regional differences in penguin pre-breeding foraging areas did not significantly affect their POP burdens, whereas the trans-equatorial migration and foraging sites of skuas were strongly reflected in their pollutant profiles, especially for PBDEs and DPs. Overall, our results provide new insights on migratory birds as biovectors of POPs, including non-globally regulated compounds such as DP, from northern regions to Antarctica.

Corvids congregate to breeding colonies of a burrow-nesting seabird

Egg predation is a major cause of reproductive failure among birds, and can compromise the viability of affected populations. Some egg predators aggregate near colonially breeding birds to exploit the seasonal increase of prey resources. We investigated spatial and temporal variations in the abundance of an egg predator (little raven Corvus mellori; Corvidae) to identify whether ravens aggregate spatially or temporally to coincide with any of three potential prey species: burrow-nesting little penguin (Eudyptula minor; Spheniscidae), short-tailed shearwater (Ardenna tenuirostris; Procellariidae), and surface-nesting silver gull (Chroicocephalus novaehollandiae; Laridae). We derived spatially explicit density estimates of little ravens using distance sampling along line transects throughout a calendar year, which encompassed little penguin, short-tailed shearwater and silver gull breeding and non-breeding seasons. High raven abundance coincided temporally with penguin and gull egg laying periods but not with that of shearwaters. The spatial distribution of raven density corresponded with the little penguin colony but not with shearwater or gull colonies. Thus, the presence of little penguin eggs in burrows correlated strongly with little raven activity, and this implies that little ravens may have learnt to exploit the plentiful subsurface food resource of little penguin eggs. Corvid management may be required to maintain the viability of this socially and economically important penguin colony.

Older female little penguins Eudyptula minor adjust nutrient allocations to both eggs

How individuals allocate resources to reproduction is a fundamental concept in animal life history theory. While it is crucial to quantify the relative allocation of somatic reserves to reproduction by avian females; variation at the individual and intra-clutch level has generally been neglected. We investigated nutrient allocation to eggs of little penguins (Eudyptula minor, Forster, 1781) using automated body-mass recording and natural δ13C and δ15N values for plasma and blood cells of incubating females, and down feathers of their chicks. Further, we evaluated the role of female age (a proxy for experience or senescence) and condition as drivers of individual strategies within this population. Little penguins increased their body masses during a short period prior the onset of reproduction, suggesting that they were accumulating resources to cope with reproductive requirements. Estimated endogenous contribution to eggs was relatively low (~20%), and female age was revealed as a major factor modulating individual variations in resource allocation strategies. Older females accumulated larger amounts of reserves before laying (up to 40% body mass increases) and relied more on endogenous resources (up to 45%) for clutch production than younger females. Our findings suggest that females were able to adjust their endogenous investment between their two chicks, with somatic reserve inputs to heavier siblings showing a bimodal distribution (mean±SD; 16.7±5.9% and 36.5±4.4%) that contrasted with the unimodal distribution observed for lighter siblings (17.8±8.7%). Here, we provide evidence pointing to age and age-related changes as major factors modulating individual decisions on the amount of somatic reserves allocated to eggs. We additionally identified two distinct allocation strategies at the intra-clutch level that may favour siblings with greater chances to fledge, revealing a novel clutch size reduction strategy in seabirds that produce two eggs of similar size but involving a differential nutrient investment in eggs.

Human tissue kallikrein 9 in asthmatic patients

albumin in the ISAC test, confirming that IgE binding in the ISAC and ImmunoCap assays was not nonspecific in view of the patient’s elevated total IgE level. It is of interest that sensitivity to the Gal d 5 a-livetin serum albumin (molecular weight 69 kDa) is responsible for the bird-egg syndrome in egg yolk and bird feather extracts.2 Major allergenic bands of similar size to those identified in our patient to penguin serum (molecular weights 20e30 kDa and 67 kDa) have been found in IgE immunoblots of budgerigar, parrot, pigeon, canary, and hen sera, which cross-react with other bird species.3 Previous sensitization and pigeon serum proteins could have increased the risk of our patient’s reaction to cross-reacting or novel African penguin proteins, because the molecular weights identified in the penguin serum (25þ 66 kDa), mucus, and feces are similar to those identified in bird-egg syndrome and bird fanciers asthma, but this would require enzyme-linked immunosorbent assay inhibition studies for further exploration. One of the reasons for the decline in penguin populations has been the illegal consumption of penguin eggs by local populations. To date, allergy to penguin eggs has not yet been reported. Penguin serum albumin has a molecular weight of 66,000 kDa (identified to bovine serum albumin), and a unique pen albumin (61,000 kDa) in antarctic (eg, Adelie) penguin eggs has a high carbohydrate content (15%) and antifreeze properties.4 These proteins have not been characterized in the African penguin. Occupational contact dermatitis resulting from handling fish food (eg, herring in a dolphinarium)5 and other foods6 has been reported, andwe believe our patient’s chronic eczemawas acquired previously from fish handling without glove protection. The acquisition of work-related asthma to exposure to the penguins and their aerosolized feces in our patient indicates that atopy might be a risk factor for asthma development in penguin curators in aquariums around the world. It is recommended that penguin enclosures be well ventilated to decrease the risk of inhalation and sensitization and clinical allergy to penguin, but also to fish proteins, in atopic workers. Further characterization of the

Chlorinated, brominated and fluorinated organic pollutants in African Penguin eggs: 30 years since the previous assessment

The African Penguin population has drastically declined over the last 100years. Changes in food availability due to over-fishing and other oceanographic changes seem to be major causes. However, it has also been 30years since organic pollutants as a potential factor have been assessed. We analysed penguin eggs collected in 2011 and 2012 from two breeding colonies 640km apart: Robben Island near Cape Town on the Atlantic Ocean coast, and Bird Island near Port Elizabeth on the Indian Ocean coast of South Africa. We quantified organochlorine pesticides, brominated flame retardants, and perfluorinated compounds (PFCs). Compared to 30years ago, concentrations of ΣDDT have remained about the same or slightly lower, while ΣPCBs declined almost four-fold. The use of DDT in malaria control is unlikely to have contributed. PFCs were detected in all eggs. Indications (non-significant) of eggshell thinning associated with ΣDDT and ΣPCB was found. It seems therefore that the concentrations of measured organic pollutants the African Penguin eggs are not contributing directly to its current demise, but concerns remain about thinner shells and desiccation. Effects of combinations of compounds and newer compounds cannot be excluded, as well as more subtle effects on reproduction, development, and behaviour.

Out of sight but not out of mind: corvids prey extensively on eggs of burrow-nesting penguins

Context Egg depredation is a major cause of reproductive failure among birds and can drive population declines. In this study we investigate predatory behaviour of a corvid (little raven; Corvus mellori) that has only recently emerged, leading to widespread and intense depredation of eggs of a burrow-nesting seabird (little penguin; Eudyptula minor). Aims The main objective of this study was to measure the rate of penguin egg depredation by ravens to determine potential threat severity. We also examined whether penguin burrow characteristics were associated with the risk of egg depredation. Ravens generally employ two modes of predatory behaviour when attacking penguin nests; thus we examined whether burrow characteristics were associated with these modes of attack. Methods Remote-sensing cameras were deployed on penguin burrows to determine egg predation rates. Burrow measurements, including burrow entrance and tunnel characteristics, were measured at the time of camera deployment. Key results Overall, clutches in 61% of monitored burrows (n = 203) were depredated by ravens, the only predator detected by camera traps. Analysis of burrow characteristics revealed two distinct types of burrows, only one of which was associated with egg depredation by ravens. Clutches depredated by ravens had burrows with wider and higher entrances, thinner soil or vegetation layer above the egg chamber, shorter and curved tunnels and greater areas of bare ground and whitewash near entrances. In addition, 86% were covered by bower spinach (Tetragonia implexicoma), through which ravens could excavate. Ravens used two modes to access the eggs: they attacked through the entrance (25% of burrow attacks, n = 124); or dug a hole through the burrow roof (75% of attacks, n = 124). Burrows that were subject to attack through the entrance had significantly shorter tunnels than burrows accessed through the roof. Conclusions The high rates of clutch loss recorded here highlight the need for population viability analysis of penguins to assess the effect of egg predation on population growth rates. Implications The subterranean foraging niche of a corvid described here may have implications for burrow-nesting species worldwide because many corvid populations are increasing, and they exhibit great capacity to adopt new foraging strategies to exploit novel prey.