Heart rates (fh) and rates of oxygen consumption (V(dot)O2) were measured in eight black-browed albatrosses (Diomedea melanophrys) when walking on a treadmill, with the aim of using fh to predict V(dot)O2 in free-ranging albatrosses. The resulting relationship between the variables was: V(dot)O2 (ml min-1) = [0.0157fh (beats min-1)]1.60, r2=0.80, P<0.001. In addition to the calibration procedure, six of the albatrosses were injected with doubly labelled water (DLW), and fh and V(dot)O2 were monitored continuously over a 3 day period while the birds were held in a respirometer. During the 3 day period, the birds were walked for up to 3­4 h day-1 in bouts lasting approximately 0.5 h. The heart rate data were used to estimate the metabolic rates of these birds using the above regression. Estimates of metabolic rate derived from fh, DLW and respirometry did not differ (ANOVA; P=0.94), primarily because of the variance between individual birds. There was also no significant difference between the different estimates obtained from the different equations used to calculate energy expenditure from the DLW technique (ANOVA; P=0.95). Mean estimates of V(dot)O2 from fh under active and inactive conditions differed from measured values of V(dot)O2 by -5.9 % and -1.7 % respectively. In addition, the estimates of V(dot)O2 from fh at different walking speeds did not differ significantly from the measured values. It appears that, in the black-browed albatross, fh is as good a predictor of the mean metabolic rate of free-ranging birds as DLW or time­energy budgets combined with either respirometry or DLW. However, the method should be applied to as many individuals and as many instances of a particular behaviour as possible. The heart rate technique offers potential for much more detailed analyses of the daily energy budgets of these birds, and over much longer periods, than has previously been possible.
In the field: an interview with Harald Wolf
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In our new Conversation, Harald Wolf talks about his fieldwork experiences working with desert ants in Tunisia to understand their navigation.
Propose a new Workshop
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Our Workshops bring together leading experts and early-career researchers from a range of scientific backgrounds. Applications are now open to propose Workshops for 2024, one of which will be held in a Global South country.
Julian Dow steps down and John Terblanche joins the JEB team
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After 15 years with the journal, Julian Dow from University of Glasgow, UK, is stepping down as a Monitoring Editor. We wish Julian all the best for the future and welcome John Terblanche, Stellenbosch University, South Africa, who is joining the team. Julian talks about his long association with The Company of Biologists and the journal and John tells us about his life and career in this News article.
The capture of crude oil droplets by filter feeders at high and low Reynolds numbers
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Researchers from the University of Montreal, Canada, reveal how tiny filter feeding barnacles and Daphnia entrap and consume minute droplets of crude oil, introducing the pollutant at the bottom of the food chain.
Patterns and processes in amphibious fish
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In their Review, Keegan Lutek, Cassandra Donatelli and Emily Standen discuss the biomechanics and neural control of terrestrial locomotion in amphibious fish. They explore how locomotor mode depends on body shape, physical constraints and phylogeny.
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