- The vast majority of research articles on bird fertility are focused on males, and are also being dominated by studies of poultry and captive populations.
- Researchers have found there are nearly twice as many papers published on male fertility traits compared to female fertility traits.
- 79% of articles on fertility were on captive birds, and more than half of these focussed on just a single species – the domestic chicken
New research from the University of Sheffield, published recently in the Royal Society Open Science journal, has revealed important gaps in our understanding of infertility in birds.
A team led by Katherine Assersohn, from the University of Sheffield’s Animal and Plant Sciences department, has outlined the physiological mechanisms that lead to fertilsation failure in female birds, highlighting where research could be directed to address the lack of information.
Females have traditionally been seen as passive participants in fertilisation. This research shows how female birds can exert far more control over fertilsation than has historically been assumed, but if and how females influence the successful fertilisation of their eggs is often ignored in favour of male processes.
Katherine Assersohn said: “The causes of infertility are generally poorly understood in non-human animals. In this review paper we find that in birds, there is a lack of knowledge on fertility in females and in wild populations. We show that the majority of published papers on bird fertility have focused on males, with research also being dominated by work on captive populations, and domestic poultry in particular.
“To begin addressing these research gaps, we have reviewed the physiological factors influencing female fertility in birds, identifying key stages during the reproductive cycle where fertility can be compromised, and highlighting important areas for future research."
In birds, an average of 10% of eggs never hatch and in threatened species this can be up to 7 times higher. The research is therefore hugely important, as a complete understanding of reproductive failure is essential to improve reproduction under management.
The team found that 79% of academic articles on bird fertility were on captive birds, with more than half of these focused on the domestic chicken.
This serves as a barrier to understanding the causes of reproductive failure of birds in the wild, damaging conservation attempts and our knowledge of reproductive failure in threatened populations.
Researchers acknowledged that a detailed study of variation in female fertility may be difficult in the wild, because information about non-breeders is hard to collect. However, they argued an effort must be made in order to manage threatened populations.
