Who are the animals here?
The birds or the group of photographers who tied a chick to a shrub just so they could get a better picture of its parents?
What Mr Jaieden Ace Shen saw on Monday shocked him.
It was his first time trying to photograph wild terns (a type of seabird) and their chicks in their habitat at Tuas South.
It was not easy and he was not the only one trying. There were three other photography buffs nearby.
That was when Mr Shen, 30, saw a photographer trying to direct a chick to a spot so its picture could be taken. The chick was not cooperative.
"Then one of them, the guy in red, tied one of the chick's legs together before attaching it to the shrub. It took him quite a while.
"After that, the chick was screaming as it fell down repeatedly, struggling to escape," he recounted.
"While all this was happening, the guy who did the tying and his female companion snapped close-up shots of the parents circling very close to the ground where the chicks were," he said.
The trio in front of him had initially "shoo-ed" the chicks to where they had set up for shots, but "the chicks kept running back to their original hideout," Mr Shen told The New Paper.
Although he was rooted for 10 minutes, "shocked, confused, and upset while witnessing this cruel act", he still managed to secretly document everything.
He said he was too scared to intervene and left after 10 minutes.
"I'm deeply ashamed for being cowardly and for not doing anything about it.
"But it was a stressful moment as I was all alone in a very secluded place I've never been to before and with three total strangers," he said.
It was only after consulting a few friends that he decided to post the photos of the act online that night, first on the wall of the Singapore Bird Group, then on his own.
"Being a newbie and not affiliated with any birding cliques or groups, I was also worried for my own safety should I bump into them again on one of my expeditions," said the introvert, who usually prefers to go bird-watching alone.
The pictures angered both bird and photography enthusiasts.
Many called the act "sick" and "cruel".