Female-dependent factors affect sex allocation in Lesser Kestrels Falco naumanni

What is it about?

Parental investment involves not only raising the young. Females are known to be able to establish the sex of the embryo at laying the eggs. The question that arises is, which is the preferred sex? Theory protends that the larger females in dimorphic species ensure fitness in future generations but are more energetically expensive to raise. Hence, we attempt to elucidate the age- and body-size-related parameters that possibly influence the sex ratios in the clutches of the different Lesser Kestrel (Falco naumanni) females in our next-box colony in Armenio, Greece. Our results suggest that larger females, in better body condition, preferentially fledge a larger proportion of female offspring.

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