Back in 2010, I was given the task of confirming breeding of the peregrines that were territorial on the 3 Cooling Silo’s that have graced the skies since 1962 on this Kent coastline.
Having been sent photos of the 3 silo’s and a tall chimney and studied them, there was not a niche or ledge visible that would offer a nest site to the peregrines, I remember thinking perhaps they nested off site and just favoured the Power Station site.
Juveniles had been seen pretty regularly over the years on site so they were obviously breeding somewhere.
I headed down there on the 1st survey in the hope that I could find the nest site.
The 3 Silo’s were impressive, built in 1962 and 300 foot high they absolutely dominated the area and surrounding landscape for miles.
The basic design was concrete with a narrow opening at the top; it then dropped down, pinched in slightly at the waist and then fanned out at the bottom half. The ground section had an opening all round of around 8 metres high, it was around 80 metres radius at the base of the Silo. There was a massive area of water, presumably this was for cooling, held up on massive pillars, I looked up inside and thought where the hell could they possibly nest?
There appeared nowhere either internal or external.
My arrival was at dawn, at the start of the breeding season, as many will know prime time for peregrine activity. I settled down to watch them so that I could cover all 3 Silo’s and the single chimney.
Plenty of activity early on with the single chimney being used as a hunting launch point by both Falcon and Tiercel, prey was taken and also copulation took place, I again checked all the higher levels on the 3 silo’s.
There was nowhere high up.
In the end it was the Tiercel who gave the game away late morning, I was watching him from distance perched on the very top of one of the Silo’s and he simply disappeared as I was watching him.
He had not flown out from the top of the Silo but had quite simply dropped down inside it!
I was perplexed as I had checked all of these Silo’s inside and out higher up, I made my way over there to have a look inside.
When I got close and looked inside, there was the Tiercel on the far side sitting on a concrete ledge on the side of the Silo, no more than 10 metres off the ground. It had never occurred to me to look this low down, other than a stashing ledge for prey this had to be the nest site.
On seeing me he flew out of the bottom section and I scoped the ledge from the other side, years of guano staining were evident, this had to be it.
It also meant that the Tiercel had dived vertically down internally around 270 odd feet before levelling out over the expanse of water and landing on the ledge. Bloody spectacular to say the least, in the coming months I saw this repeated many times from the top, I could never observe it from the inside due to Schedule 1, and not wanting to disturb them, but I imagine it must have been quite a stunning sight as they dropped off the top internally.
There means of exit from the inside of the Silo was the 8 metre high opening all around, if the ledge was the nest site it meant fledging over water and then exiting through the opening. Not easy for maiden flight juveniles but nothing is ever seemingly straightforward with peregrines is it?
Despite the fact that they could enter from the bottom, I rarely observed this over the 2 years, most entries to the nest site were from the top with only occasional entries from the bottom.
In subsequent visits, I was able to confirm over the 2010 and 2011 breeding seasons that this was indeed their regular nest site as they fledged 2 broods – 5 juveniles and 4 juveniles’ respectively.
Having been sent photos of the 3 silo’s and a tall chimney and studied them, there was not a niche or ledge visible that would offer a nest site to the peregrines, I remember thinking perhaps they nested off site and just favoured the Power Station site.
Juveniles had been seen pretty regularly over the years on site so they were obviously breeding somewhere.
I headed down there on the 1st survey in the hope that I could find the nest site.
The 3 Silo’s were impressive, built in 1962 and 300 foot high they absolutely dominated the area and surrounding landscape for miles.
The basic design was concrete with a narrow opening at the top; it then dropped down, pinched in slightly at the waist and then fanned out at the bottom half. The ground section had an opening all round of around 8 metres high, it was around 80 metres radius at the base of the Silo. There was a massive area of water, presumably this was for cooling, held up on massive pillars, I looked up inside and thought where the hell could they possibly nest?
There appeared nowhere either internal or external.
My arrival was at dawn, at the start of the breeding season, as many will know prime time for peregrine activity. I settled down to watch them so that I could cover all 3 Silo’s and the single chimney.
Plenty of activity early on with the single chimney being used as a hunting launch point by both Falcon and Tiercel, prey was taken and also copulation took place, I again checked all the higher levels on the 3 silo’s.
There was nowhere high up.
In the end it was the Tiercel who gave the game away late morning, I was watching him from distance perched on the very top of one of the Silo’s and he simply disappeared as I was watching him.
He had not flown out from the top of the Silo but had quite simply dropped down inside it!
I was perplexed as I had checked all of these Silo’s inside and out higher up, I made my way over there to have a look inside.
When I got close and looked inside, there was the Tiercel on the far side sitting on a concrete ledge on the side of the Silo, no more than 10 metres off the ground. It had never occurred to me to look this low down, other than a stashing ledge for prey this had to be the nest site.
On seeing me he flew out of the bottom section and I scoped the ledge from the other side, years of guano staining were evident, this had to be it.
It also meant that the Tiercel had dived vertically down internally around 270 odd feet before levelling out over the expanse of water and landing on the ledge. Bloody spectacular to say the least, in the coming months I saw this repeated many times from the top, I could never observe it from the inside due to Schedule 1, and not wanting to disturb them, but I imagine it must have been quite a stunning sight as they dropped off the top internally.
There means of exit from the inside of the Silo was the 8 metre high opening all around, if the ledge was the nest site it meant fledging over water and then exiting through the opening. Not easy for maiden flight juveniles but nothing is ever seemingly straightforward with peregrines is it?
Despite the fact that they could enter from the bottom, I rarely observed this over the 2 years, most entries to the nest site were from the top with only occasional entries from the bottom.
In subsequent visits, I was able to confirm over the 2010 and 2011 breeding seasons that this was indeed their regular nest site as they fledged 2 broods – 5 juveniles and 4 juveniles’ respectively.
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| The eggs must have been laid on concrete it appears |
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| 2010 - 5 juveniles |
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| Another angle |
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| Juveniles with adult and prey |
To this day the 2010 brood is the only time I have ever had 5 juveniles, one was lost and I found it drowned in the water, a sad event but the rest I am glad to say made it.
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| Juveniles - only 1 lost over the 2 breeding seasons |
The site and the 3 Silo’s were demolished in 2012 – see link
https://www.youtube.com/watch?v=x-w9q864a7E
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