White-tailed eagles mature and breed for the first time when they are 5-6 years old. They form monogamous, life-long pair bonds, although if one of the pair dies, the survivor will readily find a new mate.
Displays and nesting
White-tailed eagles are long-lived birds, with an average adult life span of 21 years, but some reaching 25 years or more. The oldest recorded individual was thought to be about 32 years old.
The breeding season is characterised by frequent loud calling, especially by the male in the vicinity of the eyrie, sometimes taking the form of a duet between the pair. Eagles have a characteristic aerial courtship display which includes flying together, calling and touching talons. They can also be seen ‘talon grappling’. This culminates in two birds locking claws mid-air, whirling earthwards in a series of spectacular cartwheels, and separating sometimes only a few feet above the ground or water and soaring upwards again. This is thought to be more of a territorial and aggressive interaction between an intruding male or female and the resident birds.
Both birds build the nest from twigs and branches, lined with rushes and grasses. They can use the nest on and off for many years, and since new material is added every time, it can attain an enormous size. They will also frequently build new nests especially following a failure to breed successfully the previous year.
Male and female roles
The female lays two or three dull white eggs 2-5 days apart in March or April, and starts to incubate with the first egg for 38 days per egg. She does most of the incubation. The eggs hatch a few days apart. Although the chicks are quite tolerant of each other, there is competition between them, the older one being dominant.
The female does most of the brooding and direct feeding of the young, but the male takes over now and then. He provides the female and the young with all food for the first three weeks after the chicks hatch, after which the female joins in hunting. The young feed themselves in the nest when they are 5-6 weeks old. They fledge at 10-11 weeks and remain close to the nest, dependent on their parents, for a further 5-6 weeks.