In Wales, Glesni has laid her clutch of three eggs. Photo courtesy Dyfi Osprey Project.
It’s early May, and all over the northern hemisphere, ospreys are starting their families. They’ve spent some time sprucing up the nursery, lining the nest with soft materials like grass, and females should be laying their eggs right about now.
Male and female ospreys return from their winter holidays separately (more info on migration here). Sometimes, a male arrives to find an interloper in the nest and must chase him off. Sometimes, a mate does not return. At the Dunrovin Ranch in Montana, Harriet was left without a mate when Ozzie died last summer. Harriet arrived back at the ranch this spring, did some renovations in the nest, and waited nearly three weeks for a new mate to arrive. Enter Heiko, a sleek young male who needs to learn a thing or two about being a parent.
A female osprey will lay her eggs 10 to 30 days after she and her mate have arrived at their summer nest. The eggs are mottled, with reddish-brown blotches on a creamy coloured background. They are a little larger than a chicken egg. Usually a female will lay 3 eggs a few days apart. Young females sometimes lay only two eggs, but rarely will a female lay four. Bird enthusiasts are keeping a close eye on osprey nests – many via nest cameras – awaiting the eggs.
The clutch (eggs) will be incubated for 35 to 45 days. The female spends the most time on the nest, particularly at night, and the male will hunt for both of them. Extreme temperatures or exposure can put the eggs at risk, and marauders like crows, eagles, raccoons, and even other ospreys may attack the nest. On April 28, Heiko and Harriet successfully defended their nest from aggressive birds.
The six weeks or so before hatching seem to take forever! If you are watching the nest cams, there is still potential for drama as the relationship develops between the nesting pair. Nature always seems to toss in a few surprises, like a hail storm.
Eventually the eggs will begin to hatch. They don’t all hatch at the same time – they weren’t all laid at the same time! The first may hatch as many as five days before the last. This launches the chicks into their first test of survival, as the oldest chick will have a head start. But that’s the subject of another blog. For now, we watch and wait for the eggs with great anticipation.
