Breaking News – A New Resident Female
It’s now over four weeks since the traumatic scenes at Leicester Cathedral were captured on our webcams. The intrusion by a female falcon at the nest on April 27th, that led to the failure of the clutch with just a few days remaining before the four eggs started to hatch. We know from our watch days and independent reports that intruding birds were not unusual in the city and the resident pair have always fought them off. It is our belief that this pair of Peregrines have been breeding in the city at a number of sites since at least 2013. We are relatively sure that the same female has been active since that time so she would be in the region of ten years old or more, and therefore an experienced and successful individual.
There had been a number of recorded incursions into the territory since the start of 2020, not unusual, but they were seemingly more frequently reported. Unfortunately, due to the Covid-19 Lockdown, no one could physically visit the Cathedral after the last week of March to observe or confirm what had been happening. It was my assumption that the actions of the pair during the period were indicative of an intruding bird(s), but I could not be 100% certain.
Since the event on 27 April, I have been watching with deepening interest as to what would unfold and what the future was for the site; was this the start of a long-term battle for the territory? We are limited in what can be seen from the webcams but I have reviewed hundreds of hours of activity both before and after the event and to say that I have been perplexed by what I have seen is an understatement; this is now what I believe happened.
On 3 April, the female left in a hurry, calling loudly, almost damaging the eggs on exit. Things then seemed quiet until 12 April when the female leaves in a hurry again during mid-afternoon and also on the 15th, 16th and 22nd. On 23 April, she flies out calling loudly early in the morning and the pair got very agitated (especially the male). Later in the day, around 19:40, the male drops onto the platform in a panic and almost knocks the female from the eggs, he is obviously very distressed, and the female flies out returning ten minutes later. There appears to be another incursion the following day. Early in the morning of the 25th, the female stands on the platform looking agitated and calling loudly and throughout the day she keeps leaving the eggs unexpectedly. From early morning on the 26th, there was a lot of calling and flying in and out haphazardly. At around 13:55, a passing Peregrine was captured on camera flying very close to the nest – the first confirmation that an intruding bird was in fact present in the area.
On 27 April, the female is on the eggs until the male arrives at 3:30 and takes over incubation whilst the female sits on the platform. The intruding falcon can be seen flying past the platform at 3:40. After a while, the resident female sits on the ledge and starts to doze. The male flies out at 5:00 and the female returns to the eggs. The male lands on the platform at 5:20 and is joined by the female. There is a lot of calling and he flies out and she follows soon after.
The next activity is the male landing briefly at 6:50 and leaving immediately on the arrival of a female a few seconds later. After checking lots of videos and screengrabs, it is now my belief that this is the intruding female and the first time she has landed on the platform. It would also account for some unusual behaviour by ‘the female’ over the next 24 hours. She goes into the box and kicks one of the eggs on her route to the rear of the box. She walks towards the eggs and stands slightly on one whilst she is continually looking around. She does not incubate the eggs but instead hops over them and goes into the corner still calling. She then walks onto the platform calling and looking all around the sky before returning to the box. Again, she ignores the eggs but instead makes a scrape in the opposite side of the box. She then goes back onto the platform, still calling. She takes a short flight at 7:20 but is back in the box five minutes later still calling and makes another small scrape and is then back on the platform looking out into the sky and calling. She walks towards the eggs but ignores them and once again makes a scrape, this time quite an extensive one, right next to the eggs. She sits on the ledge at 7:45 scanning the sky, and seems to have settled only calling occasionally, then returns to the box after ten minutes. Once again, she ignores the eggs and flies out at 8:00. The male lands a few moments later (presumably to incubate the eggs) but is buzzed by the intruding female who lands. She walks to the platform calling incessantly and flies out at 8:10. The male flies in at 8:25 and covers the eggs remaining on them until the altercation starts at 10:55 when he flies out when the intruding female arrives.
The bird defending the box is now known to be the intruder and the attacking female with the blood-stained chest was the resident. The struggle between the two well-matched females (both ringed on their right legs) lasted for over two hours and certainly took its toll physically and most probably mentally. Not only were they comparable in size but also similar in plumage and there was very little to separate them easily. At one stage or another each bird had the upper hand, but the opponent always fought back. Both birds ended up injured, each being on the receiving end of powerful, sustained talon grabs to the chest. There were long periods of fighting with rests in between, and loud and incessant calling. It ended with both females falling from the platform with talons still interlocked. There was the distinct possibility that neither would survive the fall unless they disentangled. A cliff-hanging scene worthy of an episode of any soap!
The ‘victorious’ intruding female returned to the box at 13:20, about ten minutes after falling from the platform, flying off after a further ten minutes. The male arrives 15 minutes later and covers two of the eggs. He looks at the other out-lying eggs but does not bring them closer until 14:10 when he just about manages to get a third egg under his wing. He flies out five minutes later, is back after a further five but leaves as soon as the intruding female lands at 14:20. She goes into the box calling, initially ignoring the eggs but then pulls two of the eggs towards her but does not incubate them. She then pushes them aside and creates another scrape. The male arrives looking well fed at 14:25 (probably to incubate the eggs) but puts the brakes on when he sees the female in the corner of the box. There is a couple of minutes of calling and head bobbing between the two. He keeps looking into the sky, keeping his distance on the platform, whilst the female sits in the box. He quickly flies off. The intruding female walks to the ledge and he flies in. Once again there is distant posturing before the female moves back into the box, still calling. She moves the two eggs once again but does not cover them. It looks like she is unsure what to do and just stands over them, tapping them with her beak occasionally, then walking off. At 14:55, she finally stands by the eggs and starts to doze. All the while, the male sits on the ledge looking in and it appears he has already accepted that the new female will be his partner. He flies off at 15:15 and she follows. He returns ten minutes later and is buzzed twice whilst on the platform and flies off when the new female arrives, but she does not stay long. The male is back at 15:30 but leaves when the new female arrives. She flies off ten minutes later. The male incubates the two eggs at 15:45 but leaves at 16:10, again as soon as she flies in. She ignores the eggs and flies out at 16:45 to be replaced by the male who covers them. He is off again when she flies in at 17:20, leaving five minutes later. He is back on the eggs at 17:45 leaving at 18:20 when the female arrives. She stands over the eggs but does not incubate them. She walks to the platform and at 18:40 and lies down in the stones for 15 minutes! She then flies off and the male is back to continue incubation until she returns at 20:35 and he leaves. She stands in the box before moving to the platform ten minutes later. She sits on the ledge facing into the box at 21:20 – a position the resident female never used. She remains there until 4:50 the following morning.
In summary: there had been an intruding female in the area for most of April and things began to escalate towards the end of the month. A passing intruder was caught on camera on the 26th and it appears this bird took over the nest site on the morning of the 27th. The fight that ensued later that morning was of the intruding female defending the nest site against the resident bird who had already received a blood-stained injury to the chest, no doubt from a fight earlier in the morning away from the cameras. We therefore had a new female in residence. The male could not intervene as he is much too small and could have been fatally injured. He will readily accept a new partner to allow his genes to continue. All the activity between the male and female since the 27th has been a new period of courtship. It may well be that the new female is a relatively young adult and inexperienced as the male has been more dominant than I noticed previously. It seems unlikely that they will have any new viable eggs this late in the season. And so: A new chapter begins at Leicester Cathedral.
This accounts for a number of anomalies: why did she not properly incubate the eggs after 5:15 on the morning of the 27th? Why was it only the male incubating? Why did he always leave when the female arrived or kept his distance until later in May? Why was she generating new scrapes despite there being eggs which could/would have been viable? Why was she sitting in positions on the ledge and in the box that she previously had not done? Why was there so much ‘new courtship posturing’ since the fight? Why there was no copulation on the ledge (as there had been earlier in the year) in readiness for a replacement clutch?
What it does not answer is why would a new female incubate the eggs of a previous female; albeit only for a couple of short periods (one lasting about an hour)? Possibly the innate drive to nest, due to her hormone level? What happened to the original female?
So, you may ask, why did I review all the video again? Well, besides causing me great consternation because certain actions and interactions did not add up, there is a third camera which is not being streamed that was fitted this year to try and capture the ring numbers of the resident pair. I have managed to put together the full number for the male (details awaited) and a few partial numbers for the female. When I tried to add some recent numbers to screenshots I took in March, they did not match and the only explanation was the two-bird theory. As soon as I identified that the intruding bird took over the site earlier than first thought, everything fell into place – I think! Even as I write this, I keep checking the identity of the birds!