Viblanc VA, Mathien A, Saraux C, Viera VM,
Groscolas R.
Université de
Strasbourg, Institut Pluridisciplinaire Hubert
Curien, Département Ecologie, Physiologie
et Ethologie, Strasbourg, France.
Birds may allocate a significant part of
time to comfort behavior (e.g., preening,
stretching, shaking, etc.) in order to
eliminate parasites, maintain plumage integrity,
and possibly reduce muscular ankylosis.
Understanding the adaptive value of comfort
behavior would benefit from knowledge on the
energy costs animals are willing to pay to
maintain it, particularly under situations of
energy constraints, e.g., during fasting. We
determined time and energy devoted to comfort
activities in freely breeding king penguins
(Aptenodytes patagonicus), seabirds known to
fast for up to one month during incubation
shifts ashore.
A time budget was estimated from focal and
scan sampling field observations and the energy
cost of comfort activities was calculated from
the associated increase in heart rate (HR)
during comfort episodes, using previously
determined equations relating HR to energy
expenditure. We show that incubating birds spent
22% of their daily time budget in comfort
behavior (with no differences between day and
night) mainly devoted to preening (73%) and
head/body shaking (16%). During comfort
behavior, energy expenditure averaged 1.24 times
resting metabolic rate (RMR) and the
corresponding energy cost (i.e., energy expended
in excess to RMR) was 58 kJ/hr. Energy
expenditure varied greatly among various types
of comfort behavior, ranging from 1.03
(yawning) to 1.78 (stretching)
times RMR. Comfort behavior contributed 8.8-9.3%
to total daily energy expenditure and 69.4-73.5%
to energy expended daily for activity. About
half of this energy was expended caring for
plumage.
This study is the first to estimate the
contribution of comfort behavior to overall
energy budget in a free-living animal. It shows
that although breeding on a tight energy budget,
king penguins devote a substantial amount of
time and energy to comfort behavior. Such
findings underline the importance of comfort
behavior for the fitness of colonial
seabirds.
Comprendre
la valeur adaptative des comportements
d'entretien: la pandiculation
Les oiseaux peuvent passer une part
importante de leur temps à des
comportements d'entretien d'eux-mêmes
("faire ses plumes", pandiculer, se
secouer) afin d'élimeiner des parasites;
maintenir l'intégrité de leur
plumage, et peut-être réduire
l'ankylose articulaire.
Comprendre la valeur adaptative des
comportements d'entretien peut enrichir nos
connaissances sur le coût qu'ils
représentent pour l'animal, en
particulier compte-tenu des contraintes
énergétiques (jeûne). Les
auteurs ont calculé le temps et
l'énergie dépensée par des
pingouins royaux en liberté (Aptenodytes
patagonicus), connus pour jeûner un mois
pendnat la couvaison à terre.
