LAST week I watched via a camera hidden inside the nest of wild kestrel as five chicks hatched successfully, their downy feathers still wet as they emerged from the shells.

I’ve seen this process many times now, but I had a particular interest in these young lives as they are the prodigy of a male kestrel that has been visiting my garden for 10 years.

These new chicks represent his second clutch of the year. But, shockingly, they are the offspring of a new, younger mate. He already has another family nesting nearby.

Kestrels usually pair for life and this male and his long-term partner have been nesting in my garden for long enough for me to have got to know them both well – to the point where I’ve even noticed that the male’s feathers have gone a little grey lately. I nicknamed the male Kes, after the 1967 Ken Loach movie, since I know him almost as well as any pet.

I leave food out for him and for Mrs Kes every day and whistle as I do so to let them know it’s there – they usually swoop in to fetch it right away.

Mrs Kes is brooding five chicks just 100 yards away in another box. This means Kes has a total of 10 chicks to care for in his ripe old age.

I was quite shocked when I first discovered the infidelity. Due to the nest cameras I installed this year, I had been privy to Old Mr and Mrs Kes’ entire courtship process.

This had involved the endearing ritual of trying to persuade her to accept the nest box he chose for her. He enticed her in by offering her a tasty morsel; usually a dead vole or dead day old chicken’s chick provided by me – or, if he was really out to impress her, a lizard he had caught himself – and as she entered the box he would bow his whole body up and down repeatedly, in a very comical fashion.

In April I’d seen old Mrs Kes lay her eggs. She laid one every other day and started brooding when she had her third egg, before laying two more.

So I was shocked when I first noticed another female kestrel sitting on the post where I usually put out food for Mr and Mrs Kes. I knew it wasn’t Mrs Kes since I could see her on the TV monitor, sitting patiently on her eggs.

I was even more taken aback when I spotted Kes on the monitor screens, trying to tempt her into a second nest box nearby. Each kestrel is individual and I know the markings on Kes well: the tell-tale grey tinge to the blue of the feathers on his shoulders was unmistakable.

He was clearly out to impress this young girlfriend because I noticed him offer her a lizard, which would have been among the choicest morsels he could have given.

As is often the case in these matters, this relationship only lasted two weeks before old Kes’ young girlfriend disappeared. But then I noticed yet another female on the scene. I could tell by the markings on her tail feathers, which were quite distinct from those of the other young female. I suspected this third female had pushed the other young one out of the territory.

So now here was Kes, helping to feed and care for old Mrs Kes, while also courting a younger model. I watched him rush from one to the other with choice morsels.

Despite his new relationship, old Mr Kes didn’t neglect his duties to his wife as she sat during the long dull days of incubation patiently keeping the eggs warm in the first nest box.

After 30 days Mrs Kes’ eggs began to hatch. Then, the very next day, the new girlfriend laid her first egg.

Mr Kes’ schedule hotted up. He would spend the day hunting for his new chicks while also finding time take turns brooding his other bird’s eggs.

Visitors to my gallery joined me in front of the webcam monitors to watch, incredulously, as he rushed between both nests.

I’m not sure how old Mr Kes will cope now that he has 10 new mouths to feed but I admire him for the way he has managed so far.

Kestrels in the UK feature on the RSPB’s amber warning list of species in decline. At least here on the Yorkshire Wolds, Kes is making his own particular contribution to restoring populations.