Menu

Javascript is not activated in your browser. This website needs javascript activated to work properly.
You are here

Small birds almost overheat while feeding their young

For decades, researchers have thought that access to food determined the brood size of birds. Now, biologists at Lund University in Sweden have discovered a completely new explanation: the body temperature of small birds can increase by more than 4°C to exceed 45°C when they are feeding their young. Larger broods would require more work, resulting in even higher body temperatures - something the birds would probably not survive.
Baby blue tits with mouths open in nest (Photo by Johan Nilsson)
Blue tits (Photo: Johan Nilsson)

“A body temperature of over 45°C must be close to fatal even for small birds”, says Jan-Åke Nilsson, professor at Lund University.

Small birds, passerines, normally have a body temperature of around 41°C. Jan-Åke Nilsson and his colleague Andreas Nord studied marsh tits, discovering that their body temperature increased considerably as they worked hard, for example when feeding their young.


Flying back and forth to the nest means they do not get the opportunity to get rid of excess heat, resulting in a higher body temperature.

In addition, the study shows that the tits’ body temperature follows the surrounding temperature. When the weather is warm, the birds’ body temperature increases.

“If the climate becomes warmer, it could make small birds more vulnerable. Warmer springs would force them to produce and raise fewer offspring because they cannot feed them as often without risking death”, says Jan-Åke Nilsson.

The researchers conducted the study by manipulating the brood size of the tits, making the broods larger or smaller. This enabled them to increase the variation in how hard the birds were forced to work. When the parents returned to the nesting box, the researchers measured their body temperature.

“It is interesting to observe that the marsh tits’ physiological systems worked even with fluctuations in temperature of the magnitude we have shown. Imagine how humans would feel if our body temperature increased by 4°C”, concludes Jan-Åke Nilsson.

Publication: Testing the heat dissipation limit theory in a breeding passerine

Contact:
Jan-Åke Nilsson, professor
Department of Biology
Lund University
+46 705 26 18 14
jan-ake [dot] nilsson [at] biol [dot] lu [dot] se

Categories

Latest news

17 January 2019

Body-painting protects against bloodsucking insects

Body-painting protects against bloodsucking insects
15 January 2019

Promising bioplastic derived from “poo molecule”

Promising bioplastic derived from “poo molecule”
14 January 2019

Economist with focus on inequality receives new Swedish prize in economics and management

Economist with focus on inequality receives new Swedish prize in economics and management
10 January 2019

New honorary doctors in science at Lund University

New honorary doctors in science at Lund University
20 December 2018

Antennal sensors allow hawkmoths to make quick moves

Antennal sensors allow hawkmoths to make quick moves