Foraging plasticity in Chilean flamingos: influence of water depth, food abundance and intra-flock distances

Abstract

In a natural context, many avian species exhibit the ability to assess and balance factors such as food availability, food quality, and energy expenditure when making foraging decisions. However, avian behaviours can also diverge from the predictions, influenced by a range of variables, including social behaviours, predation pressures, and individual personalities. Chilean flamingos, popular social birds native to South America, remain relatively underexplored in terms of their foraging ecology and the interplay between environmental conditions and foraging behaviours, especially within the context of conservation. To address this knowledge gap, we conducted a comprehensive study, collecting monthly physical and biological data from foraging flocks of Chilean flamingos at Lagoa do Peixe National Park, a vital contra-nuptial site located in southern Brazil, spanning from October 2021 to September 2022. We employed Generalized Linear Mixed Models to establish correlations between this dataset and the relative frequency and duration of four identified foraging behaviours: Pecking up, Head-dipping, Feet-trembling, and Dredging. Our findings substantiate that the foraging patterns exhibited by Chilean flamingos in this region are intricately linked to the trade-off between energy expenditure and the rewards obtained, primarily influenced by factors such as lagoon depth and the availability of food resources. Moreover, our results unveil a parabolic pattern in the distances maintained between individual flamingos in the flock, potentially attributed to facilitate foraging dynamics within larger groups, despite the concurrent increase in aggressive interactions. In summary, our study underscores the multifaceted variables that influence the foraging strategies of Chilean flamingos in a significant contra-nuptial area in southern Brazil. It sheds light on the behavioural adaptability of these birds and underscores the potential repercussions of this dynamic on individual and population performance and fitness.

Highlights

• Water depth, food type and food availability are the main variables influencing the foraging behaviors of Chilean flamingo in a natural environment;

• There are a trade-off between energetic reward and energetic expenditure while performing different foraging behaviors;

• The intra-flock distance also influence the foraging behaviors characteristics, with a balance between intraspecific competition and foraging facilitation;

Key Words:

• feeding behaviour
• foraging ecology
• Phoenicopteridae
• optimal foraging theory
• trade-off

ACKNOWLEDGMENTS

We thank the Lagoa do Peixe National Park for helping with logistics and accommodation during fieldwork and for the support to conduct this research.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the authors.

ETHICAL STANDARD

The methods of observation and data collection employed in this study adhere to a stringent protocol aimed at preventing any form of human interference with the Chilean flamingo population in the designated areas. The approach aims to have minimal impact on their natural behaviours while mitigating any potential stress to the birds. Observers stationed themselves discreetly, maintaining a safe distance from the animals and allowing for a habituation period. Moreover, the collection of water and sediment samples was conducted with utmost care to minimize stress on the local fauna. The method protocol underwent thorough scrutiny and received approval from the Sistema de Autorização e Informação em Biodiversidade (SISBIO), the Brazilian organization responsible for overseeing ethical and impactful considerations in scientific research. The study was conducted under the SISBIO 81,081 license, ensuring adherence to ethical standards and environmental protection measures.

AUTHOR CONTRIBUTION

H.C. Delfino and C.J. Carlos conceived the paper. H.C. Delfino collected the data, performed the statistical analysis, and drafted the initial version. All authors engaged in discussions, shared ideas, and collaborated on subsequent drafts.

SUPPLEMENTAL DATA

Supplemental Data for this article can be accessed at https://doi.org/10.1080/03949370.2024.2307025

Additional information

Funding

H.C. Delfino is supported by a PhD fellowship from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and C.J. Carlos was supported by a Postdoctoral fellowship from the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).