Using feather corticosterone to assess the effects of non-breeding season conditions on breeding of Atlantic puffins (Fratercula arctica) and rhinoceros auklets (Cerorhinica monocerata)

In order to fully understand factors that affect animals during distinct parts of their annual cycle, it is important to consider that processes acting in one season may carry over to influence an individual’s success in the following season. Measuring conditions over multiple seasons and life history stages allows carry over effects to be identified and places an individual's current condition into a broader context. Corticosterone levels measured in blood reflect hypothalmic-pituitary-adrenal (HPA) activity in birds in response to challenges that threaten homeostasis. Circulating corticosterone is integrated into growing feathers and can provide physiological information about birds during times when they are unavailable for blood sampling. Here, we used a commercially-available enzyme immunoassay kit to measure corticosterone in alcid feathers, demonstrated the benefits of acetonitrile/hexane purification of samples, and showed that blood and feather corticosterone are biologically-meaningful, albeit non-identical, measures. We used our enzyme-immunoassay and purification method in tandem with stable isotope analysis to measure corticosterone and stable isotopes in feathers and blood collected from rhinoceros auklets Cerorhinca monocerata nesting on three widely-dispersed colonies during years with different oceanographic conditions. We found that individuals from different colonies could be distinguished by their δ15N and δ13C stable isotope values during, but not prior to the breeding season, and that corticosterone levels were consistent with this pattern. Furthermore, we found that rhinoceros auklets had significantly lower corticosterone levels in a year and on a colony assumed to have less favourable feeding conditions, which is opposite to results for other taxa. In a relative of the rhinoceros auklet, the Atlantic puffin Fratercula arctica, we found that egg mass increased in relation to female corticosterone and δ15N values in feathers grown in the months prior to breeding, indicating that physiological state of females prior to the breeding season can influence egg mass. In contrast, we found that pre-breeding corticosterone and δ15N values of rhinoceros auklet females were not correlated with egg mass or egg protein levels (pilot study). Overall our results support our hypotheses that corticosterone levels vary with environmental conditions and that differences in corticosterone levels during pre-breeding correlate with egg size in the subsequent season (breeding). However, our results also indicate that interpreting these relationships requires careful consideration of ecological and physiological characteristics of the individual or taxa in question

Episodic-like memory in purebred and crossbred Yucatan minipigs (Sus scrofa)

Episodic memory is a human ability that involves mental re-creation of a personally experienced past event. Its existence is controversial in animals because it requires demonstration of self-consciousness and mental time travel. Episodic-like memory (simultaneous recall of what, where, when aspects of a past event) has been demonstrated in non-humans and appears to depend on the hippocampus. We explored the potential for episodic-like memory in pigs, a previously un-studied species reported to have high mental capacity. As was done for rats, we adopted a definition of episodic-like memory that equates recall of time ("when") with recall of context ("which"). We tested pigs' ability to remember what (object), where (location) and which (context). Through novel object recognition, pigs identified the less familiar of two object/location/context configurations. Since configuration familiarity differed only if all aspects were remembered simultaneously, we concluded that pigs were able to recall what/where/which, providing evidence of episodic-like memory

Data from: The chemical basis of a signal of individual identity: Shell pigment concentrations track the unique appearance of Common Murre eggs

In group-living species with parental care, the accurate recognition of one’s own young is critical to fitness. Because discriminating offspring within a large colonial group may be challenging, progeny of colonial breeders often display familial or individual identity signals to elicit and receive costly parental provisions from their own parents. For instance, the Common Murre (or Common Guillemot: Uria aalge) is a colonially breeding seabird that does not build a nest and lays and incubates an egg with an individually unique appearance. How the shell’s physical and chemical properties generate this individual variability in coloration and maculation has not been studied in detail. Here, we quantified two characteristics of the avian-visible appearance of murre eggshells collected from the wild: background coloration spectra and maculation density. As predicted by the individual identity hypothesis, there was no statistical relationship between avian-perceivable shell background coloration and maculation density within the same eggs. In turn, variation in both sets of traits was statistically related to some of their physico-chemical properties, including shell thickness and concentrations of the eggshell pigments biliverdin and protoporphyrin IX. These results illustrate how individually unique eggshell appearances, suitable for identity signaling, can be generated by a small number of structural mechanisms

The chemical basis of a signal of individual identity: shell pigment concentrations track the unique appearance of Common Murre eggs.

In group-living species with parental care, the accurate recognition of one's own young is critical to fitness. Because discriminating offspring within a large colonial group may be challenging, progeny of colonial breeders often display familial or individual identity signals to elicit and receive parental provisions from their own parents. For instance, the common murre (or common guillemot: Uria aalge) is a colonially breeding seabird that does not build a nest and lays and incubates an egg with an individually unique appearance. How the shell's physical and chemical properties generate this individual variability in coloration and maculation has not been studied in detail. Here, we quantified two characteristics of the avian-visible appearance of murre eggshells collected from the wild: background coloration spectra and maculation density. As predicted by the individual identity hypothesis, there was no statistical relationship between avian-perceivable shell background coloration and maculation density within the same eggs. In turn, variation in both sets of traits was statistically related to some of their physico-chemical properties, including shell thickness and concentrations of the eggshell pigments biliverdin and protoporphyrin IX. These results illustrate how individually unique eggshell appearances, suitable for identity signalling, can be generated by a small number of structural mechanisms.& 2019 The Author(s) Published by the Royal Society. All rights reserved. This document is the authors' final accepted version of the journal article. You are advised to consult the published version if you wish to cite from it

Ocean-wide drivers of migration strategies and their influence on population breeding performance in a declining seabird

Which factors shape animals’ migration movements across large geographical scales, how different migratory strategies emerge between populations, and how these may affect population dynamics are central questions in the field of animal migration [1] that only large-scale studies of migration patterns across a species’ range can answer [2]. To address these questions, we track the migration of 270 Atlantic puffins Fratercula arctica, a red-listed, declining seabird, across their entire breeding range. We investigate the role of demographic, geographical, and environmental variables in driving spatial and behavioral differences on an ocean-basin scale by measuring puffins’ among-colony differences in migratory routes and day-to-day behavior (estimated with individual daily activity budgets and energy expenditure). We show that competition and local winter resource availability are important drivers of migratory movements, with birds from larger colonies or with poorer local winter conditions migrating further and visiting less-productive waters; this in turn led to differences in flight activity and energy expenditure. Other behavioral differences emerge with latitude, with foraging effort and energy expenditure increasing when birds winter further north in colder waters. Importantly, these ocean-wide migration patterns can ultimately be linked with breeding performance: colony productivity is negatively associated with wintering latitude, population size, and migration distance, which demonstrates the cost of competition and migration on future breeding and the link between non-breeding and breeding periods. Our results help us to understand the drivers of animal migration and have important implications for population dynamics and the conservation of migratory species

North Atlantic winter cyclones starve seabirds

Each winter, the North Atlantic Ocean is the stage for numerous cyclones, the most severe ones leading to seabird mass-mortality events called “winter wrecks.” During these, thousands of emaciated seabird carcasses are washed ashore along European and North American coasts. Winter cyclones can therefore shape seabird population dynamics by affecting survival rates as well as the body condition of surviving individuals and thus their future reproduction. However, most often the geographic origins of impacted seabirds and the causes of their deaths remain unclear. We performed the first ocean-basin scale assessment of cyclone exposure in a seabird community by coupling winter tracking data for ∼1,500 individuals of five key North Atlantic seabird species (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia, and Rissa tridactyla) and cyclone locations. We then explored the energetic consequences of different cyclonic conditions using a mechanistic bioenergetics model and tested the hypothesis that cyclones dramatically increase seabird energy requirements. We demonstrated that cyclones of high intensity impacted birds from all studied species and breeding colonies during winter but especially those aggregating in the Labrador Sea, the Davis Strait, the surroundings of Iceland, and the Barents Sea. Our broad-scale analyses suggested that cyclonic conditions do not increase seabird energy requirements, implying that they die because of the unavailability of their prey and/or their inability to feed during cyclones. Our study provides essential information on seabird cyclone exposure in a context of marked cyclone regime changes due to global warming