The significance of the eagle
Almost 641 sea-eagle bones, the remains of at least eight birds, were found inside the Isbister cairn and earned the site its nickname - The Tomb of the Eagles.
These magnificent birds, with their two-metre wingspan, were once common in Orkney and the quantity of eagle remains inside the cairn – apparently found not only in the structures foundations but also alongside the human remains and later infill - prompted the theory that the birds held some special significance to the cairn builders and were perhaps a totem animal.
But more recent research appears to show otherwise.
In 2006, the publication of radiocarbon dates from eagle bone recovered from Isbister suggested that the birds were not deposited by the original builders. Instead, the birds were actually placed in the cairn up to 1,000 years after it was built.
The dates, obtained in a project by Finbar McCormick, Queens University Belfast, and Alison Sheridan, National Museums of Scotland, revealed that the eagles had died between 2450 BC and 2050 BC.
So what does this mean to the cairn?
What it confirms is that Orkney’s chambered cairns remained a focus of activity for centuries after their construction and initial period of use.
At Isbister, although the original tomb builders may not have regarded the eagles as particularly significant, over the following centuries there was a change.
The rise of the sea-eagle
The nature of this change is open to debate.
Was there a change in the population? Did a new group of people take up residence in the area or was it simply a gradual change in the belief system or the builders’ ancestors?
Or could there have been a more mundane reason, such as the initial appearance of sea-eagles in the area, or perhaps an increase in their number?
Did the sea-eagle come to symbolise the tribe, who came to regard it as a sacred animal.
If so, was it connected it to the rituals undertaken in and around the cairn? Or was it merely placed in the cairn as an offering?
At Isbister, like Orkney's other chambered cairns, the bones of the deceased were brought in and stored in communal groups - a fact that indicates the flesh was removed from the corpses before they were interred.
Did the sea-eagles become connected to the excarnation process? Tearing the flesh from a laid-out body, were the feeding birds seen as carrying the soul or spirit of the dead to the otherworld or perhaps seen as mythical protectors, interred with the ancestors to guard them in the afterlife?
Theories abound but unfortunately, like many other aspects of ancient Orkney, we will never fully know the truth.