Avian gut microbial communities are complex and play a fundamental role in regulating biological functions within an individual. Although it is well established that diet can influence the structure and composition of the gut microbiota, foraging behaviour may also play a critical, yet unexplored role in shaping the composition, dynamics, and adaptive potential of avian gut microbiota. In this review, we examine the potential influence of coprophagic foraging behaviour on the establishment and adaptability of wild avian gut microbiomes. Coprophagy involves the ingestion of faeces, sourced from either self (autocoprophagy), conspecific animals (allocoprophagy), or heterospecific animals. Much like faecal transplant therapy, coprophagy may (i) support the establishment of the gut microbiota of young precocial species, (ii) directly and indirectly provide nutritional and energetic requirements, and (iii) represent a mechanism by which birds can rapidly adapt the microbiota to changing environments and diets. However, in certain contexts, coprophagy may also pose risks to wild birds, and their microbiomes, through increased exposure to chemical pollutants, pathogenic microbes, and antibiotic-resistant microbes, with deleterious effects on host health and performance. Given the potentially far-reaching consequences of coprophagy for avian microbiomes, and the dearth of literature directly investigating these links, we have developed a predictive framework for directing future research to understand better when and why wild birds engage in distinct types of coprophagy, and the consequences of this foraging behaviour. There is a need for comprehensive investigation into the influence of coprophagy on avian gut microbiotas and its effects on host health and performance throughout ontogeny and across a range of environmental perturbations. Future behavioural studies combined with metagenomic approaches are needed to provide insights into the function of this poorly understood behaviour.

中文翻译：

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食粪觅食行为对禽类肠道微生物组的影响

禽类肠道微生物群落非常复杂，在调节个体生物功能方面发挥着重要作用。尽管饮食可以影响肠道微生物群的结构和组成已是公认的事实，但觅食行为也可能在塑造禽类肠道微生物群的组成、动态和适应潜力方面发挥着关键但尚未探索的作用。在这篇综述中，我们研究了食粪觅食行为对野生鸟类肠道微生物组的建立和适应性的潜在影响。食粪涉及摄入来自自身（自食）、同种动物（同种动物）或异种动物的粪便。与粪便移植疗法非常相似，食粪可以（i）支持年轻早熟物种肠道微生物群的建立，（ii）直接和间接提供营养和能量需求，以及（iii）代表鸟类可以快速适应微生物群的机制。改变环境和饮食。然而，在某些情况下，食粪也可能通过增加对化学污染物、病原微生物和抗生素抗性微生物的接触而对野生鸟类及其微生物组构成风险，对宿主的健康和性能产生有害影响。考虑到食粪对鸟类微生物组的潜在深远影响，以及缺乏直接调查这些联系的文献，我们开发了一个预测框架，用于指导未来的研究，以更好地了解野生鸟类何时以及为何进行不同类型的食粪，以及这种觅食行为的后果。需要全面研究食粪对禽类肠道微生物群的影响，及其在整个个体发育和一系列环境扰动中对宿主健康和性能的影响。未来的行为研究需要与宏基因组方法相结合，以深入了解这种知之甚少的行为的功能。