Curious: how do light levels explain the weaverbird eggs variety of colours?
Kam-Yung Soh

having never been to sub-saharan Africa to see these birds myself, i am going to make a guess. i suspect these birds, which are reported to nest in a wide range of habitats from open to semi-open habitats, are either specialising on a particular sort of habitat (forest vs riparian areas) or their bodies can sense light levels and adjust pigments in the eggs appropriately. i am assuming that colour variations exist between different birds’ clutches, and possibly between one clutch and another (depending upon location), and that all the eggs in each clutch that the birds lay will be the same colour.