December 3rd 2022 Introduction
NaturalEngland have given their agreement for several Drone surveys to take place at Parliament, there has been some loose masonry and the Drone surveys are site wide to catalogue, photograph and record all the stonework prior to works. Similar to the Elizabeth Tower which took a few years, this will be much the same.
Obviously in the breeding season the work would be licensable and as such, at a breeding site would require a licence from NaturalEngland.
My role in this has been to monitor the resident pair of peregrines to try and avoid any conflict with the Drone. The key thing here to reduce the risk, is always to know where they are always positioned, and visually if not viewable, to have a good position to be able to see if they are approaching. The more airspace you can see the better, less chance of being surprised if you can see one or both approaching.
Whilst static, watching body language and being able to hear them is a must, obviously its better if they have fed, sitting there with a bulging crop and more lethargic, depending on the time of year, they are hopefully inclined to be less aggressive. Victoria Tower
As part of the wider based Drone surveys taking placed at Parliament, this survey directly targeted one building – Victoria Tower.
This structure as we know is the breeding site of the pair, it houses their nest box, it is where they spend much of the time resting, roosting, feeding, and caching prey. As such it is their ‘core’ structure at Parliament for the very highly territorial pair.
As it was late in the year now, thankfully the 3 juveniles have now left so it was only the resident pair to consider. I cannot speak for NaturalEngland, but if the 3 juveniles were still present earlier in the Autumn, I would have advised against it. A Drone to a young peregrine who is still learning the ropes, chasing and practicing aerial attacks on passing birds, large or small may be too much of a carrot to resist. With 3 present, excitable, and tail chasing/practicing on each other, I would see it as far too much of a risk, even out of the main licensable breeding season.
Of all the Drone surveys to date, there has been others, this was the survey that could possibly provide the most risk of reaction and aggression from the adults. This was due to the very strong breeding link to Victoria Tower and an even stronger link to the nest box. Survey
The 1st flight went up at 9.35a.m, having noted both peregrines positions – the Falcon was on Central Spire and the Tiercel away west, I opted to undertake the potential riskiest side of Victoria Tower – the eastern elevation nest box face. With the pair not present on Victoria Tower, this was the best opportunity.
This I considered, to be the face which offered greater possible reaction to the Drone, possibly triggering aggression and possible alarm/stress.
I was in constant contact with the Drone operator by Walkie Talkie, we had a procedure if there was a reaction, basically drop-drop-drop and I obviously had the Drone in view at all times. Conclusion
For the most part I have to say that both peregrines ignored the Drone when they were present until late afternoon, on 2 occasions previously they showed some slight reaction earlier, with both bird’s stress calling mildly and flying to the nest box and alighting in it, or just above it. Coupled with the calling this was a Drone reaction, albeit fairly mild and lacking aggression as such but more a defence action.
It was noted that the Drone had changed camera on 2 of these occasions and was going slightly closer on both these periods, the Drone was on the east face and not far from the nest box. On both events also, the pair were absent at the time and arriving back from a hunting foray. I would suspect, that perched up say on Central Spire and having watched the Drone for several hours, attaining possible partial conditioning to the Drones presence, there may not have been a reaction, hard to say. After a while though, the pair left on both occasions, to resume normal activities and behaviour.
Pair - Central Spire
The most reactive and biggest encounter came on the 3rd occasion, late in the afternoon, in bad light when the birds were possibly looking to roost on Victoria Tower. The Drone was on the east face again at a fair elevation, fairly close to Victoria Tower, at the time both birds were on the Abbey but were then lost to view behind buildings as they flew.
As the Drone got close to Victoria Tower, both birds suddenly appeared and started to circle above the Drone, not that high above it and it was noted that both birds were stress calling.
As they circled, the Falcon undertook a very shallow mock dive at the Drone, nowhere near it, but showing slight intent, so in communication over the walkie talkie, the Drone was dropped immediately, this they did, and we then called it a day as the light was also going.
After this they, immediately alighted on Victoria Tower. Thoughts
Although Peregrines are no respecters of size when it comes to territorial defence, say from bigger birds of prey, I think in this case the size of the Drone may have helped.
This Drone measured 1.1 metres across so it was of a fair size, the mindset is that a smaller Drone may possibly have stimulated a stronger reaction. I have seen peregrines reactions to smaller Drones; however, this could be coincidental, different pairs, different reaction.
The fact of the matter is that you cannot apply one pairs reaction and logic to every pair and expect the same results. Each pair is individually different, younger pairs are likely more excitable and in turn more aggressive and seeing a Drone for the first time, may well bring on a more aggressive response.
With far more human activity in an urban scenario, it could be that urban pairs, as opposed to rural pairs, have a higher threshold to what constitutes disturbance and reaction, however again this is only based on this pair.
The fact of the matter is, that every pair is different and based on this, Drones should not be flown at a Peregrines nest site, the outcome and reaction to each individual Drone flight cannot be predicted.
Territoriality, all year round in London, goes with the species and there will always be the danger present of the peregrine attacking the Drone.
However, in this case at Parliament, it is necessary due to Health and Safety, it is also providing good data and feedback on Drones.
With works due to start on Victoria Tower, a new nest box with a ledge is being installed closer to the river, facing east as per the normal nest box, it is slightly lower down but hopefully they will take to it.
For 2023 the old box will be closed off but then reopened in the future when works are complete.