FUZHOU, Feb. 1 (Xinhua) -- For many Spring Festival is a time to go back home, but for Huang Shiyun and Huang Jiayun, it is a time to pack up and leave for a strange place thousands of kilometers away.

The sisters are part of a group called "little migratory birds" -- children left behind in their countryside home who travel to cities to meet their parents during the holidays.

The sisters' parents work in a factory in Fuzhou, southeast Chinas Fujian Province, over 2,000 kilometers away from their hometown Mujiangchong village, Longchang city, southwest China's Sichuan Province.

In the previous years, their parents, like millions of migrant workers, would go back home for family gatherings. This year, grandma decided to travel east with her grandchildren for new year.

Currently there are 6.97 million "left-behind" children in China, whose parents have moved away from home to pursue higher salaries in more well-off regions.

BITTERSWEET HOME

Tucked among endless small hills, rice paddies in Longchang produce meager yields, forcing many villagers to travel away from home for a better income.

Left behind under their grandma's care, the two sisters live a tranquil life, playing hopscotch around their house or wondering in the fields picking wild flowers.

But they miss their parents lots, longing for summer and winter vacations when the family can be together for a short period of time.

"When I miss them, I like to play in daddy and mommy's bedroom upstairs because it feels as if they are there," Shiyun, 9, said.

When she cannot contain the loneliness, she calls her parents. "They said they missed me too, and told me to study hard and take care of my grandma and little sister."

She has never let her parents down. As class monitor, she is the best student in class. The wall of their living room is covered with 19 awards she won from school, along with eight earned by her younger sister.

Shiyun is also a good farm hand. She helps her grandma do household chores, keeping chicken and ducks, harvesting sweet potatoes and drying grain in the sun.

I MISS YOU, MOMMY

At 4 p.m. they hit the road, carrying bulging bags loaded with farm specialties such as dried bamboo shoots and glass noodles.

Although high-speed trains have greatly slashed travel time for many Chinese, it is still an arduous journey to travel from the countryside in the southwest to the eastern coast.

First, they take a bus to the nearby Chongqing Municipality, where they spent a night before boarding the high-speed train to Fuzhou. The train is sparsely occupied, as the travel rush ahead of the new year is mostly an exodus from coastal areas to the countryside inland.

However, a reversal has emerged with more people choosing to gather with their family in the big cities, as they found that trips from home to the cities could be much cheaper and the traditional thinking that new year should be celebrated in hometowns is changing.

Before long, Shiyun has made some new friends, most of whom are left-behind children traveling to cities to join their parents for the holiday.

The heat and the dull rumble of the train soon sends the children to sleep. After she wakes up, Shiyun starts to read comic books to her bleary-eyed sister.

After some fitful sleep, the wearied sisters stumble off the train in Fuzhou south railway station.

As soon as they see their parents at the arrival gate, they rush into their mother's arms crying "I miss you, mommy!"

The father keeps kissing his daughters on the cheek.

It took them a further hour on bus to their final destination, a suitcase factory located in the city's suburb.

The sisters' 28-hour journey is nothing special at this time of the year, when many Chinese are on the move for family gatherings or sightseeing.

Nearly 3 billion trips are expected to be made during the 40-day-long travel rush. For many, seeing their families is a once-a-year event.

HOME IS WHERE THE FAMILY IS

A single 20-square-meter room is the shelter for the family of five now. A bed, a sofa and a makeshift wardrobe comprise nearly all their furniture.

Huang Haoran, the 40-year-old father, feels guilty about this.

At the age of 14, he became a migrant worker. He has worked at the assembly lines, managed a retail pharmacy, and in 2011 he started a workshop making lady's bags. However, the small factory went bankrupt two years ago, and he ended up on the assembly line again.

He now works as a shearer and his wife works a lathe in a suitcase factory.

He blames himself for failing to provide a decent life for his family and for not spending enough time with the children.

The parents are adamant that their daughters should have a different life when they grow up.

"We want them to go to college," said Huang Haoran. "That is why we pay so much attention to their study."

The parents once considered sending the sisters to schools near the factory, but hesitated because they were not sure how long they will stick with their present jobs, and whether the children would fit in well with the new environments.

The girls are happy about their new year presents: each has a new backpack and a cute pig doll.

Shiyun and her sister say their present to their parents is that they both rank first place in the school examination. These little migratory birds look set to fly high.