Kfir Bibas, with his red hair and pink stuffed elephant, was less than nine months old when Hamas militants snatched him from his bed in an Israeli kibbutz on October 7.

The youngest hostage to be kidnapped by the Palestinian Islamist group was born on January 18 and -- if still alive -- would be celebrating his first birthday this week.

His family marked the occasion with a cake and candles at kibbutz Nir Oz.

In November, Hamas broadcast a video announcing the death of the baby, his brother and mother. 

But there has been no confirmation from Israeli officials, and relatives have since clung to the hope that they are not dead.

Had Kfir still been there, his birthday would probably have looked like this week's celebration, "with music and happy voices, and smiles and family and friends," said Yossi Schneider, cousin of the baby's mother Shiri Bibas.

"Not with sounds of planes and shooting," he added, as the squawking of parakeets in the cactus-filled kibbutz mingled with explosions and bursts of machine gun fire from fighting in the nearby Gaza Strip.

"It's crazy that we're planning a birthday (for) somebody that's not here," he said, during a press visit to the kibbutz organised by "Bring them home now", a group of families of the hostages.

That we are "doing things that are related to a birthday -- but the birthday kid is not here." 

As a plane roared overhead, Schneider said he had a message for Kfir and the baby's mother: "We are thinking about them every day, every second, every minute."

Birthday decorations and a cake with a picture one-year-old hostage Kfir Bibas at the Kibbutz Nir Oz nursery.

The Gaza Strip is less than three kilometres (two miles) away and a black plume of smoke rises from the outskirts of Khan Yunis, the main focus of recent Israeli army operations in the territory.

At least 24,448 Palestinians, more than 70 percent of them women, children and adolescents, have been killed in Gaza in Israeli bombardments and ground operations since October 7, according to the health ministry of the Hamas government.

- 'Nobody flying to save him' -

The kibbutz has been deserted since the Hamas attack on October 7, which resulted in the death of around 1,140 people in Israel, most of them civilians, according to an AFP tally based on official Israeli figures.

Militants also dragged about 250 hostages back to Gaza, 132 of whom Israel says remain there, including at least 27 believed to have been killed, according to an AFP tally based on the latest data.

Out of the roughly 400 inhabitants of the Nir Oz kibbutz, about one in four was either killed or kidnapped.

While 40 have been released, most of them during a week-long truce in late November, around 30 remain in Gaza.

Among them is Kfir, who was abducted along with his four-year-old brother Ariel and their parents Yarden and Shiri Bibas.

Israelis are haunted by the image of Shiri clutching her children in pyjamas, her face filled with terror in front of her captors.

The Israeli authorities have announced that eight of the hostages taken from Nir Oz have died.

On the eve of Kfir's birthday, the "Bring them home now" group was keen to show his crib and sandbox under a small white building topped with a concrete anti-missile sheet.

Inside the structure, where 12 babies used to be cared for, a CD of "The Prettiest Girl in the Kindergarten", a popular song in Israel, has not been played since the surviving inhabitants of the kibbutz were evacuated.

The whiteboards that used to record the times of meals and naps remained blank. 

Ariel loved to draw Batman symbols and, according to Schneider, would ask his teacher to write underneath them: "I'm flying and saving people that (are) stuck inside of a pit".

"It's amazing that a four year old thought about it and now he's in some hole in the ground and nobody's coming," he said.

"Nobody's flying to save him."