A family of White-tailed Eagles on the Isle of Mull have astonished observers by showing a previously unknown side to their characters and some unusual behaviour which they’ve never experienced before. RSPB Mull Officer Dave Sexton tells us more…..
Last year, a sea eagle nest high in a large ash tree crashed to the ground in unseasonably wild weather at the end of July on land owned by North West Mull Community Woodlands. The two well grown chicks, on the verge of fledging, fell with it and were lost to view in the tangle of broken branches and vegetation at the remote nest site on an offshore island.
There were immediate fears that both chicks may have been killed in the incident, but soon after, one chick emerged, seemingly unscathed and was later seen to be flying well with its parents and being fed. Concerns for the second chick intensified when it was not seen for some days until eventually it was spotted on the shoreline but clearly unable to fly. Instead it was apparently walking everywhere and was sometimes not seen at all for days on end.
Eventually, by the autumn, when its sibling had long since dispersed, the injured youngster finally flew, rather wobbly, into view. It was clear its flight was very erratic and unstable but it was at least managing to get around in a limited way. It was thought highly unlikely that it would survive the long, harsh winter ahead.
Then this spring I was onboard the Lady Jayne run by Mull Charters on an early season sea eagle monitoring check to see which pairs were nesting and where. When we neared the territory of this pair, the male approached the boat as they do and scavenged a fish. As it flew back to shore, I heard the unmistakable sound of a food begging young sea eagle! It’s the kind of screech I usually hear in August after the eaglets fledge but are still being provisioned by their parents. Then, incredibly, in flew the juvenile sea eagle, chasing its parent, and calling for food. The male flew to a newly refurbished nest, followed closely by the youngster. Both landed, the male relinquished the fish and the juvenile fed. I looked at the skipper in astonishment and we both watched on, unable to quite believe what we’d just witnessed.
I was astounded to see this behaviour which was new to me despite four decades of watching sea eagles in the field. Normally, in the autumn and certainly by the winter, all fledged young have naturally wandered away from their parent’s territory and if they’re still loitering when the next breeding season approaches, they aren’t made very welcome. But here we were watching their chick, now over a year old, still in close company with its parents and still being fed!
This unusual change to their normal routine also meant that the adults are not breeding this year despite building a new nest. The continued presence of the young bird has completely disrupted their normal nesting behaviour. As this season has gone on, it’s been clear that the chick is still heavily dependant on the adults and continues to be cared for and any fish suppers are shared with it. A recent photo of the chick in flight shows a severe kink or bulge in the ‘shoulder’ joint of the left wing. We can only conclude that the chick broke its wing when the nest tree fell and that, over time, it has miraculously healed to the extent where the bird can now make short, limited flights.
For the adults to be still tolerating their young and tending to it, well into a new breeding season, is unprecedented in my experience. Each day they share fish from Mull Charters with their disabled offspring and it seems to show a previously unseen type of sea eagle behaviour. We normally think of eagles as ‘hard-wired’ and unemotional but clearly there might be another side to their nature. It’ll be fascinating to watch how long this might go on for. Could they tolerate it and feed it for another year…or two? What would happen as the immature starts to reach the sub-adult stage in 3 to 4 years’ time? It’s hard to imagine this scenario continuing by then but who knows? We’re in uncharted territory.
For now, we’re just enjoying watching this unusual sea eagle family doing what they want to do and caring for their youngster which can’t yet fend for itself. I loved sea eagles before. Now I think I love them just a little bit more.
Main image by Ashley James.