Well, the last four or five weeks have certainly been a real ‘harrier roller-coaster ‘ here on Geltsdale! And what a convoluted saga it’s been; all the harder to make sense of since the birds decided set up residence in a remote gulley that we couldn’t actually view without getting so close that we might inadvertently unsettle the birds – something we obviously wanted to avoid at all costs. This, then, is a brief summary of the events that unfolded:
An immature male (still in his beige, ‘ring-tail’ livery) was observed holding territory and building so-called ‘cock’s nests’ in a very remote part of the reserve. Cock’s nests are made by males from heather sprigs, to impress potential partners with their house-keeping abilities and readiness to breed (these ‘nests’ are never actually used to lay eggs in, as the female always builds her own nest).
At about the same time, a much darker, big adult female had also been sighted in the same area, and at least one food transfer between the two was seen. However, no sustained sky-dancing or tandem gliding was ever witnessed (though any copulation would probably not have been observed because of our restricted vantage points).
At this stage, round-the-clock surveillance was swiftly set up in order to protect both birds from any accidental/deliberate disturbance or persecution. The male was regularly seen foraging, carrying food back to the nest gulley, and even continuing to build ‘cock’s nests’ (rather unusual behaviour at this stage). However, sightings of the female, always scarce, seemed to dry up completely.
We hoped that this was because she was sitting tight whilst incubating. But after a week without seeing her we became concerned that she might not actually be there anymore.
In addition, the male was now suddenly in full-blown sky-dancing mode. He was seen up to three kilometres away in high-level advertising display – the sort of behaviour one expects when a male is trying to pull a new female. Had he indeed seen another female in the area? And was the original female still there? Males can sometimes be polygamous, servicing and provisioning more than one nesting female. Perhaps we might even get two nests?
So eventually we decided we had to go in and check the nest gulley, to find out just what was happening. But, sadly, it was not what we had hoped for. We found only a single, long-abandoned egg lying in the heather. There was no real nest, with just a couple of bits of loose heather in the vicinity (almost looking as though they had been dropped in as an afterthought).
The female had obviously now deserted the site, leaving her one unhatched egg behind. This was indeed a bitter blow, given all our efforts. So, what had happened here? Was this a case of predation, not enough food being supplied by the male, or something else? All the observational and physical evidence has proved inconclusive, so we’ll probably never know the true cause of failure for sure. All in all, a most disheartening sequence of events for the whole wardening team.
But our disappointment soon turned to fresh hope, as our male was now to be seen in the company of a new female – herself also a young bird. Was this the bird he was earlier trying to impress with his spectacular aerobatic display? The birds were observed together sky-dancing, close tandem flying, and dropping into areas of leggy heather – all typical behaviour when birds are pair-bonding and looking to select a nest site. This activity continued for a couple of days across a large swathe of suitable ground, and optimism was again high.
However, frustratingly, since then we’ve had only sporadic sightings of solo ring-tails. And as our young harriers are both very pale-plumaged individuals, it is usually quite difficult to say which bird we’re watching unless they’re together for direct size comparison. No nest-building or food-carrying has yet been witnessed, so the signs, realistically, are not all that promising.
Even if they hang around, have these immature birds got the drive, experience and energy to embark on a risky nesting attempt at this late stage of the season? With every day that passes, the likelihood of success seems to be waning. But, who knows, there could still be yet another twist in this convoluted tale. And so we continue our long vigil in hope...