Heart rate as a predictor of energy expenditure in undisturbed fasting and incubating penguins

Abstract

SUMMARYHeart rate (f H ) measurement offers the possibility to monitor energy expenditure (EE) in wild animals if the EE/f H relationship for the species, physiological stages and activities of interest is known. This relationship has been extensively studied using oxygen consumption rate (V O2) measurement in captive, repeatedly handled king penguins (Aptenodytes patagonicus). Unfortunately, the potential effects of stress on the observed relationships resulting from handling and confinement were not considered. This study is the first involving undisturbed animals, and determines the EE/f H relationship in naturally fasting and freely incubating or captivity-acclimatized male and female king penguins. EE determination was based on (1) the measurement of body mass loss during periods of phase II fasting, and (2) the calculation of its energy equivalent from changes in body composition, i.e. 23.9kJg. f H levels in freely incubating and captivity-acclimatized birds were found to be 50-70% lower than those previously reported for resting king penguins during V O2 measurements. Significant EE/f H relationships were found in freely incubating and captive males and females (R

Modulation of heart rate responses to acute stressors throughout the breeding season in a colonial seabird, the king penguin

“…Acute HR responses to stressors were measured using external HR loggers (Polar ® model RS800 and RS800CX, Polar Electro Oy, Kempele, Finland) specially adapted for use on king penguins (see Groscolas et al, 2010;Viblanc et al, 2012Viblanc et al, , 2014b. Loggers were made of two units: (1) a sensortransmitter (30-40 g) composed of a HR processor which filtered out electrical background noise received from the electrodes (i.e.…”

“…The whole apparatus weighed less than 1% of the total body mass of the smallest bird. Further details on this method and how it accurately estimates HR of king penguins are provided by Groscolas et al (2010).…”

Rovers minimize human disturbance in research on wild animals

“…Each system included two units: a sensor-transmitter (30-40 g) attached to the back of the bird and a receiver-logger (a recording watch, 30 g) placed on its flipper (see Fig. 1a) as described by Groscolas et al 20 and Viera et al 21 . Penguin HR and its changes have been well studied 3,16,20,21 and provide a sensitive measure of individual stress levels 3 .…”

“…1a) as described by Groscolas et al 20 and Viera et al 21 . Penguin HR and its changes have been well studied 3,16,20,21 and provide a sensitive measure of individual stress levels 3 . Incubating birds were handled after their heads were quickly covered from behind to mask their eyes, and handlers kneeled inside the penguins' territory for approximately 5-10 min to attach the equipment.…”

“…Moreover, the impacts of animal-borne instruments and tags on animal behavior and energetics, such as the drag costs on instrument-bearing sea turtles 5 or flipper-banded penguins 6 , can have dramatic effects that lead to scientific biases 7,8 . Such methods that have a cardio-frequency meters as previously described 20,21 . Briefly, the eyes of incubating birds were masked from behind, and the two units of equipment-a sensor-transmitter (30-40 g) attached to the back of the bird and a receiver-logger (a recording watch, 30 g) placed on a flipper-were attached to the individuals by a human kneeling inside their territory in a 5-to 10-min procedure.…”