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Saturday, 4 May 2019

Battersea Power Station - April






Where to start, a lot has happened in April to say the least, the triangular relationship between the Falcon, Immature and adult Tiercel has taken a new turn after observing copulation taking place, albeit distantly between both of the adults. 

Further to this, eggs have now been laid, quite a feat in itself given the current scenario, the father to the eggs being the adult Tiercel.

With the first egg being laid on April 9th, copulation has taken place with the Falcon flying off east to buildings/cranes where the adult Tiercel mated with her, the act undertaken she then flies back to the Power Station. Multiple daily copulation is usually needed for fertility, whether she has copulated enough is another matter in regards to eggs hatching, it could be that given the strained and irregular copulating relationship with the adult Tiercel, fertility may be an issue. I have observed copulation between the 2 adults at least 5 times in early January to the east of the site, hopefully it will be enough, there is no doubt that if they were bonded on site, copulation would happen more, we will see.

The reason behind the long distance meetings regarding copulation between the adults is that the adult Tiercel has not been able to remove the immature Tiercel. This is the single 2018 offspring of the Falcon and the previous resident Tiercel who disappeared in November 2018.Consequently the new adult Tiercel has not become territorial on site, he spends most of his time east of the site near Vauxhall, when he tries to enter the Power Station airspace he immediately clashes with the immature. I have seen this a number of times in April, with the immature seeing the adult off, it certainly happens every time I am present so I would imagine it is a daily occurrence.


A complex relationship, I had my money on the adult Tiercel replacing the immature Tiercel, I didn’t think the immature would be strong enough to keep an adult out, however despite the oddness of the relationship it may just work given that the immature has stepped up.

There is no doubt that the immature has designs on his mother, ledge display between the 2 happened quite a lot in early April, in a few months he will become an adult plumage peregrine and would likely form an incestual relationship with his mother for 2020.Obviously things could change, the father of the eggs cannot spend his time on the sidelines forever unable to fulfil his role surely.

When the first egg was laid, my first thoughts were these, how can the adult Tiercel give a nest relief (incubation changeover) or supply prey if he cannot displace the immature once she had laid the full clutch?

Additionally who will supply her with prey once she is incubating fully after 3 eggs, she cannot do both?

The answer to these questions is the immature, not only is he now supplying prey daily, he is also incubating whilst she feeds or preens before returning to the eggs.

As mentioned before, the Falcon does not interfere when the immature/adult Tiercels clash, she sometimes calls but does not intervene from what I have seen, possibly seeing which is the stronger, her offspring or the adult Tiercel?

When the immature brings in prey, as per normal she takes it from him, however she then still insists on feeding him still, a mother is a mother.



I have to say it is the strangest relationship I have come across in 20 years of watching peregrines, there is always something new to learn from them, interesting times ahead.





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