It just so happened that Ruurd Jelle van der Leij has been photographing jays in his garden for the past ten years. He needed to exert some effort because the birds belonged to the family of crows and were very intelligent. And the birds had become aware of his presence with his camera, and as a result, as he had mentioned, the birds had lost faith in the food that he had provided for them. And in addition, the birds had begun flying through his garden more quickly. After losing confidence, it had taken him well over a year to work up the courage to shoot any detailed photographs.
In addition to that, he had contemplated the number of individual birds that were there over the winter. He had spotted more than five birds, and he suspected that there were even more. During the process of gathering images, he realized that each of them might be able to be recognized as an individual by a remarkable feature that resembled a barcode in blue and black.
Ruurd had been photographing Jays in his garden for the past ten years, beginning when he started doing so.
He had discovered that each could be distinguished from the others by a remarkable black and blue feature that functions analogously to a barcode.
He had been fascinated by the birds of the crow family ever since he was a young boy. He had been looking for the blue feathers of those birds in his garden, but he had no idea that he would still be looking for them some 25 years later. During the time he spent collecting images of each different jay, it became abundantly evident that each had a unique code. When it came to recognize some of them, however, he had no trouble doing so. In contrast, for others, he needed to snap further images of the individual birds before being able to study and discern them on his computer.
In 2018, photographs of the left and right sides of ten different jays were taken.
The number of blue jays in his garden increased from five to ten throughout the winter of 2018–2019 as a direct result of his feeding and caring for the jays there. Two of them had been living in his yard for the entirety of the year and had also been reproducing there.
Specifications regarding the barcode.
When he was comparing the barcodes, he needed to look at the same side of each. According to what he had indicated, comparing the left and right sides of the bird could mean looking at the same bird twice because the design was different on each side.
Six different bird species from 2020, each with their unique barcode.
Because the birds lost their feathers, the question of whether or not the pattern also changed, as a result, was brought up. According to what he had mentioned, the design does vary. Still, the one bird in his garden for the entire year had some consistency in her code that she had retained over the years. He said this bird had been there for a whole year. He was sure she was the same bird because she was the bird in his garden that maintained the most composure.
The dominant bird replaces its feathers annually but keeps the same overall pattern.
Photographs of the left and right sides of the primary bird were grouped. It’s probably the same thing.
Ruurd was able to take images of the bird during her summer visit with her brood and then determine the total number of young.
Altogether, there were five birds, and the fact that they all had dark black bars and eyes of a pale blue colour gave the impression that they might be juveniles.
Five rules that young jays do not follow.
This winter, he had begun to keep a count, and seven jays associated with the pair had been successful in producing offspring.