Adjustments in the diving time budgets of tufted duck and pochard: is there evidence for a mix of metabolic pathways?

Carbone, C; Leeuw, J. de; Houston, Alasdair I.

doi:10.1006/anbe.1996.0130

Cited by 32 publications

(10 citation statements)

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“…In the case of air-breathing aquatic animals, time-depth recorders have been used to monitor their behaviour, as it is difficult to observe animals foraging underwater. As a result, time-based models have been developed, and empirical data have been used to test predictions derived from the models (Boyd et al, 1995;Carbone et al, 1996;Thompson and Fedak, 2001;Mori et al, 2002;Mori and Boyd, 2004). Longer transit times between the surface and the foraging depth are not beneficial in terms of time efficiency, but a longer transit time does allow birds to move horizontally.…”

Section: Discussionmentioning

confidence: 99%

Why do macaroni penguins choose shallow body angles that result in longer descent and ascent durations?

Sato

Charrassin

Bost

et al. 2004

Journal of Experimental Biology

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SUMMARY It is generally assumed that air-breathing aquatic animals always choose the shortest route to minimize duration for transit between the surface and foraging depth in order to maximize the proportion of time spent foraging. However, empirical data indicate that the body angles of some diving animals are rarely vertical during descent and ascent. Why do they choose shallower body angles that result in longer descent and ascent durations? To investigate this question, we attached acceleration data loggers to eight female macaroni penguins, breeding on the Kerguelen Islands(48°45′–50°00′S,68°45′–70°58′E; South Indian Ocean), to record depth, two-dimensional acceleration (stroke cycle frequency and body angle)and temperature. We investigated how they controlled body angle and allocated their submerged time. The instrumented females performed multiple dives(N=6952) with a mean dive depth for each bird ranging from 24.5±28.5 m to 56.4±75.1 m. Mean body angles during descent and ascent were not vertical. There was large variation in mean descent and ascent angles for a given dive depth, which, in turn, caused large variation in descent and ascent duration. Body angles were significantly correlated with time spent at the bottom-phase of the dive. Birds that spent long periods at the bottom exhibited steep body angles during ascent and subsequent descent. By contrast, they adopted shallow body angles after they had short or no bottom phases. Our results suggest that macaroni penguins stay at the bottom longer after encountering a good prey patch and then travel to the surface at steep body angles. If they do not encounter prey, they discontinue the dive,without staying at the bottom, ascend at shallow body angles and descend at shallow body angles in a subsequent dive. A shallow body angle can increase the horizontal distance covered during a dive, contributing to the move into a more profitable area in the following dive. During the ascent, in particular,macaroni penguins stopped beating their flippers. The buoyantly gliding penguins can move horizontally with minimum stroking effort before reaching the surface.

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Section: Discussionmentioning

confidence: 99%

Why do macaroni penguins choose shallow body angles that result in longer descent and ascent durations?

Sato

Charrassin

Bost

et al. 2004

Journal of Experimental Biology

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“…This was the case, for example, with studies where water depths for the particular population observed were deemed to be unusually shallow for that species (e.g., Cooper 1986). No laboratory-based data were used (e.g., Carbone et al 1996) because of the prominent confounds that experimental work often introduces into the behavior of species (Halsey et al, forthcoming). Where multiple field observations were recorded for the same species at different locations (e.g., Cooper 1986), an average was calculated for each diving variable.…”

Section: Datamentioning

confidence: 99%

A Phylogenetic Analysis of the Allometry of Diving

Halsey

Butler

Blackburn

2006

The American Naturalist

144

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The oxygen store/usage hypothesis suggests that larger animals are able to dive for longer and hence deeper because oxygen storage scales isometrically with body mass, whereas oxygen usage scales allometrically with an exponent <1 (typically 0.67-0.75). Previous tests of the allometry of diving tend to reject this hypothesis, but they are based on restricted data sets or invalid statistical analyses (which assume that every species provides independent information). Here we apply information-theoretic statistical methods that are phylogenetically informed to a large data set on diving variables for birds and mammals to describe the allometry of diving. Body mass is strongly related to all dive variables except dive:pause ratio. We demonstrate that many diving variables covary strongly with body mass and that they have allometric exponents close to 0.33. Thus, our results fail to falsify the oxygen store/usage hypothesis. The allometric relationships for most diving variables are statistically indistinguishable for birds and mammals, but birds tend to dive deeper than mammals of equivalent mass. The allometric relationships for all diving variables except mean dive duration are also statistically indistinguishable for all major taxonomic groups of divers within birds and mammals, with the exception of the procellariiforms, which, strictly speaking, are not true divers.

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“…Houston & Carbone (1992) and also predicted the non-monotonic response of optimal foraging duration to the variation of t. These theoretical predictions were experimentally tested and supported (e.g. Carbone & Houston, 1994;Carbone, De Leeuw & Houston, 1996).…”

Section: Introductionmentioning

confidence: 94%

Optimal choice of foraging depth in divers

Mori

1998

Journal of Zoology

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When prey availability depends on water depth, a diver should choose an optimal depth for foraging. A model that predicts the optimal foraging depth for a diver is presented in this paper. General predictions derived from the model are: (1) optimal foraging depth is always shallower than the depth at which prey density is the highest, even if the depth of the highest prey density is within easy reach; (2) a larger diver should make deeper and longer dives and stay longer on the surface than smaller divers for optimal foraging; (3) foraging ef®ciency of larger divers is not always greater than smaller divers, although the larger divers forage at the depth of higher prey density. These predictions, derived from the model, are consistent with the comparative studies of diving behaviour in marine birds.

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Adjustments in the diving time budgets of tufted duck and pochard: is there evidence for a mix of metabolic pathways?

Cited by 32 publications

References 0 publications

Why do macaroni penguins choose shallow body angles that result in longer descent and ascent durations?

Why do macaroni penguins choose shallow body angles that result in longer descent and ascent durations?

A Phylogenetic Analysis of the Allometry of Diving

Optimal choice of foraging depth in divers

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