Aharon-Rotman, Yaara

Körtner, Gerhard

Wacker, Chris B

Geiser, Fritz

2020-11

<p>Precocial birds hatch feathered and mobile, but when they become fully endothermic soon after hatching, their heat loss is high and they may become energy depleted. These chicks could benefit from using energy-conserving torpor, which is characterised by controlled reductions of metabolism and body temperature (T_b). We investigated at what age the precocial king quail <i>Coturnix chinensis</i> can defend a high T_b under a mild thermal challenge and whether they can express torpor soon after achieving endothermy to overcome energetic and thermal challenges. Measurements of surface temperature (T_s) using an infrared thermometer showed that king quail chicks are partially endothermic at 2-10 days, but can defend high T_b at a body mass of ~13 g. Two chicks expressed shallow nocturnal torpor at 14 and 17 days for 4-5 h with a reduction of metabolism by >40% and another approached the torpor threshold. Although chicks were able to rewarm endogenously from the first torpor bout, metabolism and T_s decreased again by the end of the night, but they rewarmed passively when removed from the chamber. The total metabolic rate increased with body mass. All chicks measured showed a greater reduction of nocturnal metabolism than previously reported in quails. Our data show that shallow torpor can be expressed during the early postnatal phase of quails, when thermoregulatory efficiency is still developing, but heat loss is high. We suggest that torpor may be a common strategy for overcoming challenging conditions during development in small precocial and not only altricial birds.</p>

The Journal of Experimental Biology, 223(21), p. 1-10

1477-9145

0022-0949

32978318

https://hdl.handle.net/1959.11/30287

The Company of Biologists Ltd

Do small precocial birds enter torpor to conserve energy during development?

Journal Article

Publication