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. (2010). Measuring foraging activity in a deep-diving bird: comparing wiggles, oesophageal temperatures and beak-opening angles as proxies of feeding.
. J. Exp. Biol., 213(Pt 22), 3874–80.
Abstract: Quantification of prey consumption by marine predators is key to understanding the organisation of ecosystems. This especially concerns penguins, which are major consumers of southern food webs. As direct observation of their feeding activity is not possible, several indirect methods have been developed that take advantage of miniaturised data logging technology, most commonly: detection of (i) anomalies in diving profiles (wiggles), (ii) drops in oesophageal temperature and (iii) the opening of mouth parts (recorded with a Hall sensor). In the present study, we used these three techniques to compare their validity and obtain information about the feeding activity of two free-ranging king penguins (Aptenodytes patagonicus). Crucially, and for the first time, two types of beak-opening events were identified. Type A was believed to correspond to failed prey-capture attempts and type B to successful attempts, because, in nearly all cases, only type B was followed by a drop in oesophageal temperature. The number of beak-opening events, oesophageal temperature drops and wiggles per dive were all correlated. However, for a given dive, the number of wiggles and oesophageal temperature drops were lower than the number of beak-opening events. Our results suggest that recording beak opening is a very accurate method for detecting prey ingestions by diving seabirds at a fine scale. However, these advantages are counterbalanced by the difficulty, and hence potential adverse effects, of instrumenting birds with the necessary sensor/magnet, which is in contrast to the less accurate but more practicable methods of measuring dive profiles or, to a lesser extent, oesophageal temperature.
Keywords: Animals, Beak, Beak: physiology, Behavior, Animal, Behavior, Animal: physiology, Body Temperature, Body Temperature: physiology, Diving, Diving: physiology, Ecosystem, Esophagus, Esophagus: physiology, Feeding Behavior, Feeding Behavior: physiology, Food Chain, Male, Predatory Behavior, Predatory Behavior: physiology, Remote Sensing Technology, Remote Sensing Technology: instrumentation, Remote Sensing Technology: veterinary, Spheniscidae, Spheniscidae: physiology,
Programme: 394
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. (2012). King penguins adjust their diving behaviour with age
. J. Exp. Biol., 215(Pt 21), 3685–3692.
Abstract: Increasing experience in long-lived species is fundamental to improving breeding success and ultimately individual fitness. Diving efficiency of marine animals is primarily determined by their physiological and mechanical characteristics. This efficiency may be apparent via examination of biomechanical performance (e.g. stroke frequency and amplitude, change in buoyancy or body angle, etc.), which itself may be modulated according to resource availability, particularly as a function of depth. We investigated how foraging and diving abilities vary with age in a long-lived seabird. During two breeding seasons, small accelerometers were deployed on young (5 year old) and older (8/9 year old) brooding king penguins (Aptenodytes patagonicus) at the Crozet Archipelago, Indian Ocean. We used partial dynamic body acceleration (PDBA) to quantify body movement during dive and estimate diving cost. During the initial part of the descent, older birds exerted more effort for a given speed but younger penguins worked harder in relation to performance at greater depths. Younger birds also worked harder per unit speed for virtually the whole of the ascent. We interpret these differences using a model that takes into account the upthrust and drag to which the birds are subjected during the dive. From this, we suggest that older birds inhale more at the surface but that an increase in the drag coefficient is the factor leading to the increased effort to swim at a given speed by the younger birds at greater depths. We propose that this higher drag may be the result of young birds adopting less hydrodynamic postures or less direct trajectories when swimming or even having a plumage in poorer condition.
Keywords: Aging, Animals, Behavior, Animal, Biomechanical Phenomena, Diving, Energy Metabolism, Female, Male, Motor Activity, Spheniscidae, Swimming,
Programme: 137
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Cunningham Gregory B, Bonadonna Francesco, . (2015). King penguins can detect two odours associated with conspecifics.
. The Journal of experimental biology, 218(Pt 21), 3374–6.
Abstract: Recent studies on olfaction in penguins have focused on their use of odours while foraging. It has been proposed for some seabirds that an olfactory landscape shaped by odours coming from feeding areas exists. Islands and colonies, however, may also contribute to the olfactory landscape and may act as an orienting map. To test sensitivities to a colony scent we studied whether King penguins (Aptenodytes patagonicus) could detect the smell of sand, feathers or feces by holding presentations beneath their beaks while they naturally slept on the beach. Penguins had a significantly greater response to the feathers and feces presentations than to sand. Although only a first step in exploring a broader role of olfaction in this species, our results raise the possibility of olfaction being used by King penguins in three potential ways: (1) locating the colony from the water or the shore, (2) finding the rendezvous zone within the colony where a chick or partner may be found, or (3) recognizing individuals by scent, as in Humboldt penguins (Spheniscus demersus).
Programme: 354
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. (2014). Variation in body condition during the post-moult foraging trip of southern elephant seals and its consequences on diving behaviour.
. J. Exp. Biol., 217(Pt 14), 2609–19.
Abstract: Mature female southern elephant seals (Mirounga leonina) come ashore only in October to breed and in January to moult, spending the rest of the year foraging at sea. Mature females may lose as much as 50% of their body mass, mostly in lipid stores, during the breeding season due to fasting and lactation. When departing to sea, post-breeding females are negatively buoyant, and the relative change in body condition (i.e. density) during the foraging trip has previously been assessed by monitoring the descent rate during drift dives. However, relatively few drift dives are performed, resulting in low resolution of the temporal reconstruction of body condition change. In this study, six post-breeding females were equipped with time-depth recorders and accelerometers to investigate whether changes in active swimming effort and speed could be used as an alternative method of monitoring density variations throughout the foraging trip. In addition, we assessed the consequences of density change on the swimming efforts of individuals while diving and investigated the effects on dive duration. Both descent swimming speed and ascent swimming effort were found to be strongly correlated to descent rate during drift dives, enabling the fine-scale monitoring of seal density change over the whole trip. Negatively buoyant seals minimized swimming effort during descents, gliding down at slower speeds, and reduced their ascent swimming effort to maintain a nearly constant swimming speed as their buoyancy increased. One per cent of seal density variation over time was found to induce a 20% variation in swimming effort during dives with direct consequences on dive duration.
Keywords: Animals, Behavior, Animal, Behavior, Animal: physiology, Biomechanical Phenomena, Body Composition, Diving, Diving: physiology, Female, Oceans and Seas, Seals, Earless, Seals, Earless: physiology, Swimming, Swimming: physiology, Telemetry,
Programme: 109
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. (2015). Modulation of heart rate response to acute stressors throughout the breeding season in the king penguin Aptenodytes patagonicus.
. The Journal of experimental biology, 218(Pt 11), 1686–92.
Abstract: 'Fight-or-flight' stress responses allow animals to cope adaptively to sudden threats by mobilizing energy resources and priming the body for action. Because such responses can be costly and redirect behavior and energy from reproduction to survival, they are likely to be shaped by specific life-history stages, depending on the available energy resources and the commitment to reproduction. Here, we consider how heart rate (HR) responses to acute stressors are affected by the advancing breeding season in a colonial seabird, the king penguin (Aptenodytes patagonicus). We subjected 77 birds (44 males, 33 females) at various stages of incubation and chick-rearing to three experimental stressors (metal sound, distant approach and capture) known to vary both in their intensity and associated risk, and monitored their HR responses. Our results show that HR increase in response to acute stressors was progressively attenuated with the stage of breeding from incubation to chick-rearing. Stress responses did not vary according to nutritional status or seasonal timing (whether breeding was initiated early or late in the season), but were markedly lower during chick-rearing than during incubation. This pattern was obvious for all three stressors. We discuss how 'fight-or-flight' responses may be modulated by considering the energy commitment to breeding, nutritional status and reproductive value of the brood in breeding seabirds.
Programme: 119
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David Grémillet. (2017). Les oiseaux marins de l'Arctique face aux changements climatiques.
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. (2012).
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. (2019). Applying science to pressing conservation needs for penguins (Vol. n/a).
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Hubert G, Federico CA, Pazianotto MT, Gonzales OL, . (2016). Long and short-term atmospheric radiation analyses based on coupled measurements at high altitude remote stations and extensive air shower modeling
. Astroparticle Physics, 74(N.A.), 27–36.
Keywords: ATMORAD, Atmospheric radiation environment, Extensive air shower, High altitude stations, Neutron spectrometer,
Programme: 1112
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. (2008). Polarization in aurorae: A new dimension for space environments studies, ., 35, L08804. GEOGRAPHICAL RESEARCH, 35(L08804).
Abstract: The polarization of emission lines is a noteworthy
observational parameter in astronomy. However, it has
never been detected without ambiguity in planetary upper
atmospheres. Theoretical considerations have suggested that
the polarization of the thermospheric oxygen red line
(630 nm) could exist in the polar cap region. We present
here its first successful measurement at Svalbard in January
2007, during active geophysical conditions. We assign its
origin and variability to complementary effects between
permanent low-energy electron precipitation and sporadic
auroral events. Implications in physics, geophysics and
planetary science are foreseen. In physics, it raises the
question of the polarization of a forbidden transition by
electron impact which is still unknown. In geophysics, it
provides a new parameter to constrain the thermospheric
models. In planetary science, it makes it possible to derive
the local configuration of the magnetic fields. It therefore
opens new perspectives for future space missions towards
other planets.
Programme: 1026
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