The breeding cycle of the White-tailed Eagle on Mull
commences in late Winter, when courtship display and
prospective nest site selection may take place.
White-tailed Eagles form life-long monogamous
partnerships once they become sexually mature. This
usually happens when birds are around five years of age,
although some individuals may be precocious and attempt
to breed at an earlier age. Two pairs of young adults
that attempted to breed on the Isle of Mull in 2011
failed due to their inexperience. White-tailed Eagles
are remarkably faithful to their partners and to their
chosen nest location. Individuals will only form a fresh
pair bond should an existing partner die.
Photo courtesy of Debby Thorne
White-tailed Eagles are long-lived, with the previous oldest
recorded bird reaching the age of 32 years. The original pair of
birds that settled to breed on the Isle of Mull in the early
1980’s have equalled this longevity record and are probably the
oldest White-tailed Eagles anywhere in the world. These
remarkable birds have chosen well in life and have reaped the
benefit of deciding to settle on the Isle of Mull all these
years ago.
Noisy Individuals
In contrast to Golden Eagles,
White-tailed Eagles can be very vocal, especially during
courtship and at the onset of the breeding season. This frequent
loud calling often takes place in the vicinity of the eyrie and
consists of a series of barks or yelping cries that increase in
tempo and pitch. Should the adults become alarmed, a loud and
far-carrying ‘klee-klee-klee(-klee)’ is uttered, often
dramatically piercing the tranquility of the Isle of Mull
countryside in early Spring.
Sky Dancers
At the dawn
of every New Year, the Isle of Mull’s White-tailed Eagle
population readies itself for the onset of yet another breeding
season. Although monogamous, individual eagles will be keen to
reaffirm their pair bonds with their existing partners and to
show fidelity with their chosen breeding territory. This they do
in a series of circling and soaring flights, often high above
the nest location.
White-tailed Eagles have a
characteristic aerial courtship display, which culminates in the
pair locking talons in mid-air and whirling earthwards at great
speed in a series of spectacular cartwheels. This death-defying
stunt may come to an end only a few feet above the ground or
water before the birds soar upwards again and can be a
thrilling, once-in-a-lifetime experience for many birdwatchers.
Talon-grappling is not confined to courtship display, however,
and may be used, by territorial birds, as a way of discouraging
intruders. Despite their fierce look and awesome power,
White-tailed Eagles often have a pacifistic approach to
confrontation, only engaging in physical combat with other birds
as a last resort.
