However, Shamshu Miah, 52, from Llandudno was released because of the time he has already spent in custody.
He admitted intentionally killing a wild bird at Llandudno boating pool and possessing a kitchen knife in public.
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District judge Andrew Shaw sitting at the town’s magistrates court said it was a “cruel and reprehensible act”.
“You killed the swan at night. It was a cruel and reprehensible act. I don’t know exactly how the animal died. There seems to be speculation you may have bitten it.”
However, the judge said he had to accept Miah’s version that he killed it with a knife.
The court heard that when he was challenged by police he told them: “I am a Muslim, I am fasting, I needed to eat.”
Jim Neary, prosecuting, said: “When interviewed he said, ‘I was hungry, I had to eat the swan so I killed it, I stabbed it. I did nothing wrong, it was just a bird, I needed to eat.'”
“The officers told him the swan was the property of the Queen and he replied, ‘I hate the Queen, I hate this country.'”
Judge Shaw added: “It’s a taboo act and the only sentence that is appropriate is imprisonment.”
Police were alerted by a householder.
The court heard a community mental health team was anxious to help Miah, who had been going through a period of instability, according to his solicitor.
He had no previous convictions.
Original headline: Hungry man who killed swan jailed