About 10 per cent of birds’ eggs fail to hatch, but
the incidence of failure can be much higher in
endangered species.Most studies fail to distinguish
between infertility (due to a lack of sperm) and
embryo mortality as the cause of hatching failure,
yet doing so is crucial in order to understand the
underlying problem. Using newly validated techniques
to visualize sperm and embryonic tissue,
we assessed the fertility status of unhatched eggs
of five endangered species, including both wild
and captive birds. All eggs were classified as ‘infertile’
when collected, but most were actually fertile
with numerous sperm on the ovum. Eggs of captive
birds had fewer sperm and were more likely
to be infertile than those of wild birds. Our findings
raise important questions regarding the
management of captive breeding programmes.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)