Bertalanffy-Pütter models for avian growth.

Area of Science:

• * Avian Ecology
• * Quantitative Biology
• * Bioenergetics

Background:

• * Understanding avian growth patterns is crucial for ecological studies.
• * Traditional growth curve models have limitations in flexibility and parameter interpretation.
• * The ratio of mass at inflection point to asymptotic mass offers insights into growth dynamics.

Purpose of the Study:

• * To explore the utility of the Bertalanffy-Pütter model for analyzing avian growth.
• * To investigate the mass ratio at the inflection point over asymptotic mass in blue tits and great tits.
• * To detect subtle environmental influences on avian growth using this ratio.

Main Methods:

• * Utilized literature data for 81 nestlings of blue tits and great tits.
• * Applied the Bertalanffy-Pütter growth model for its flexibility with growth ratios.
• * Calculated the ratio of mass at inflection point to asymptotic mass for each bird.

Main Results:

• * Observed a wide range of mass ratios, from 0 to 0.835.
• * 48 birds exhibited ratios above 0.5 (characteristic of logistic growth).
• * Blue tits showed slower growth (lower ratio) in areas with light pollution and modified impervious substrate.

Conclusions:

• * The Bertalanffy-Pütter model provides a more flexible approach to avian growth analysis.
• * The mass ratio is sensitive to environmental variations, allowing detection of subtle growth differences.
• * Environmental factors like light pollution can negatively impact avian growth rates.