Great grey owls are highly specialised predators dependent on cyclical vole populations in boreal forests, with welfare closely tied to prey abundance.
Great grey owls experience dramatic welfare variation across vole population cycles. During vole lows, adult owls struggle to find sufficient food and chicks face starvation. Irruptive southward movements during prey crashes expose owls to collision mortality, window strikes, and electrocution on power lines. Old-growth forest loss removes the large stick nests they require for breeding, forcing birds into suboptimal nest sites or preventing reproduction.