Column: Number of eggs in a nest is just enough for a pair of birds to handle

MAINE SUNDAY TELEGRAM • June 7, 2020

A highly variable feature of bird reproduction among species is clutch size – the number of eggs laid in a nest. Ruby-throated hummingbirds and mourning doves always have a clutch size of two. Herring gulls lay two or three eggs. Most songbirds have clutch sizes in the single digits. For instance, chestnut-sided warbler and black-throated green warblers lay three to five eggs. Some birds are more ambitious. The clutch size of ruffed grouse varies from nine to 14. A female wood duck lays six to 16 eggs. Why the variation? The explanations are complicated, but food availability is a major driver. ~ Herb Wilson