Related Experiment Video
Updated: Jan 10, 2026
In Ovo Feeding of Commercial Broiler Eggs: An Accurate and Reproducible Method to Affect Muscle Development and Growth
Published on: September 20, 2021
Chicks of cavity-nesting birds do not 'exercise' prior to fledging
Kate Earle1, Josh Allen1, Brett Lee Hodinka1
1Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
Insights
Starling chicks increase activity before fledging, but this exercise does not improve their physical development or aerobic capacity. Increased voluntary activity does not significantly impact somatic or physiological development prior to fledging.
Area of Science:
- Avian biology
- Animal behavior
- Life-history transitions
Background:
- Fledging is a critical life-history stage for birds, marked by a shift from sedentary nestling to active volant fledgling.
- This transition involves a significant increase in workload and demands on developing birds.
Purpose of the Study:
- To investigate if European starling chicks increase voluntary activity (exercise) before fledging.
- To determine the impact of this pre-fledging activity on somatic and physiological development.
Main Methods:
- Observed European starling (Sturnus vulgaris) chicks in cavity nests.
- Quantified wing flapping and general active behaviours (perching, standing) in the five days preceding fledging.
- Assessed facultative mass loss, wing growth, and haematocrit levels.
Main Results:
- Chicks exhibited increased wing flapping and general active behaviours leading up to fledging.
- Mass loss and wing growth were not correlated with increased activity levels.
- A negative relationship was observed between haematocrit (aerobic capacity) and time spent wing flapping or standing.
Conclusions:
- Pre-fledging exercise in starling chicks does not enhance somatic or physiological development.
- Increased activity does not appear to be a mechanism for improving pre-fledging aerobic capacity.
- Contrary to anecdotal observations in other species, increased activity in starlings does not confer developmental benefits before fledging.
Abstract:
Fledging represents a key life-history transition involving a rapid increase in workload associated with a rapid transition from sedentary nestling to volant, active fledgling. Here, we tested the idea that chicks might prepare for fledging through increased voluntary activity ('exercise') and whether this would impact somatic and physiological development. European starling (Sturnus vulgaris) chicks, in cavity nests, increased levels of putative exercise (wing flapping), and more general active behaviours (e.g. perching, standing) in the five days up to fledging. However, facultative mass loss and wing growth between days 15 and 20 were independent of time spent wing flapping, standing or perching and, counterintuitively, we found a weak negative relationship between haematocrit (a measure of aerobic capacity) and time spent wing flapping or standing. Thus, although exercise is commonly associated with an increase in haematocrit in other species, this does not appear to be a mechanism for increasing pre-fledging haematocrit in chicks. Despite widespread anecdotal observations of flight preparation (e.g. wing flapping) in larger seabirds and raptors, our data suggest that exercise, or increased activity in general, does not contribute to improved development just prior to fledging: starling chicks do not 'exercise' enough to show somatic or physiological effects.
Related Concept Videos
00:55Parental Care
00:48Optimal Foraging
02:07Conservation of Declining Populations
01:56Gastrulation
01:54Convergent Evolution
00:51Energy Budgets