OWL make excellent parents. In fact, their nurturing instinct is so deeply ingrained they will even act as surrogate mothers and raise chicks that are not their own.

Over the years I have successfully taken advantage of this protective nature to re-home wild owlets – usually owls that have been found and handed in to me by individuals or even wildlife rehabilitation centres.

Normally I put chicks into a nest when the bird’s own chicks have hatched and are already well grown.

But last month I pushed the boundaries by persuading a pair of barn owls to accept two foster chicks before their own eggs had even hatched.

A farmer had found the chicks after emptying out a barn of straw. They were less than a week old and very frail.

I decided I would use a pair of barn owls I was already monitoring via CCTV as surrogate parents for these chicks.

This way I could watch how the female took to the new chicks and intervene if things started to go awry.

So I got my ladder out and propped it against the tree supporting this pair’s nest box. As I climbed up the rungs, the chicks balanced in my left hand, the female flew out. I placed the two chicks next to her still-warm eggs and then headed back home as quickly as possible.

Back in my kitchen I could see that the female owl on the TV screen. She was standing over the chicks, looking down at them in surprise. She reached down with her beak and hesitated above them.

For a horrible moment I wondered whether she was going to brood them, or eat them. Then she touched each chick with her beak and clumsily lifted one foot and then the other as though trying to work out how to go about brooding them.

She was a new parent and these two extra owlets were her first ever chicks. She didn’t know what to do with her long sharp talons. I watched amused as she clenched her claws to get them out of the way, but managed to stand on the chicks in the process.

At one point she pecked at her own feet in frustration. Then, finally, after a lot of fidgeting, she was sitting on her new brood.

Just before midnight the male arrived in the nest box. Usually when he comes into the box he greets her and then tries to mate her. Normally when he does this, even if she is incubating the eggs, she bows her head in submission. But this time she looked him straight in the eye and pecked him.

He took a step back in confusion before stepping forward to try again. Again she rebuffed his advance, this time standing up with her wings out and pushing him around the nest box, pecking him all the while.

She forced him into the far corner and made him stay there while she returned to tend to her chicks. He watched on forlornly from the side lines, shuffling around the edges of the box.

The next morning I watched as she fed the chicks in turn, each chick neatly tucked under a wing. I was delighted that she had taken to her role with such dedication.

A week later her own eggs hatched. There was a sizable difference between the largest and smallest chick in the nest, but this didn’t overly concern me. It is perfectly natural for barn owls to have a range of differently sized young.

Barn owls incubate the first egg as soon as it is laid and then usually one egg every three days. So if they lay six, there will be 18 days between the oldest and youngest chick.

This, however, can present a very nasty problem as the largest is big enough to swallow the youngest one whole.

I’m putting out extra food for this artificially expanded family to ensure that that these four chicks will all make it to fledging time.

So far, 2015 has been a very disappointing year for breeding barn owls so it important for the populations on the Yorkshire Wolds that these young chicks survive.