Abstract
Niche partitioning is often vital for the coexistence of ecologically
similar species under limited resources. Here I will report the nesting
strategy of the two sympatric songbirds and the species differences,
which have been overlooked in the past. Blue-capped and red-cheeked
cordon-bleus are socially monogamous, biparental songbirds (family
Estrildidae) that sympatrically inhabit East Africa. My field
observation during their breeding season revealed that red-cheeked
cordon-bleus build their nests near wasp nests more frequently than
blue-capped cordon-bleus. Blue-capped cordon-bleus instead tended to
take over weaver’s old nest more often or use a broader range of nesting
materials compared to red-cheeked cordon-bleus. These nesting strategies
are already described in the literature as common behaviors in both
species. However, the species differences of the adopting strategies
have never been reported. While Estrildid finches are one of the best
well-studied bird families of their behavior under the captive
condition, my finding suggests that we still have limited knowledge of
their wild behaviors and ecological plausibility, which is required to
understand the functions and evolution.