Details

Autor(en) / Beteiligte

• Lambrechts, Marcel M.
• Caro, Samuel P.

Titel

Egg cooling associated with nest size in a passerine bird

Ist Teil von

• Journal of thermal biology, 2022-12, Vol.110, p.103383-103383, Article 103383

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2022

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• Breeders evolved adaptive responses to rapid changes in ambient temperature. In birds, nests are expected to reduce egg cooling when the incubator is temporarily off the eggs. Here we present the results of two complementary laboratory experiments aiming at testing the association between egg cooling and the thickness of the nest under and surrounding the eggs in a non-domesticated avian model species (great tit, Parus major). To simulate incubation behaviour, we exposed nests with 4-egg clutches to a heat source until the eggs reached a normal incubation temperature (ca. 39 °C) and then recorded egg cooling 8 min after removal of the heat source, which corresponds to the time females generally leave eggs unattended during the incubation period. Eggs cooled more quickly when the nest layer under the eggs was thinner and when ambient temperature was cooler. We also show that the wall around the nest cup is important to buffer egg cooling. It is hypothesised that in bird nests, both the thickness of the material under the eggs, and the wall surrounding the nest cup interact to maintain a heat envelope around the eggs for the time the incubating parent is foraging. This could explain why the thickness of the nest base and wall are adjusted to the ambient temperature the birds experience during the nest building phase, to anticipate the thermal conditions during incubation and preserve egg viability. •Bird nests are expected to protect eggs against physical and thermal damages.•Eggs cool down more slowly when the insulation material under the eggs is thicker.•The nest wall around the eggs also contributes to keep eggs warmer.•The nest architecture thus maintains a heat envelope around the unattended eggs.