What does the word “migration”, underlined in the text mean?

The Disappearing Honeybee

• Honeybees do more than just make honey. They fly around and pollinate flowers, plants, and trees. Our fruits, nuts, and vegetables rely.....................these pollinators. One third.....................America’s food supply is pollinated.....................the honeybee.

Have you seen or heard a honeybee lately? Bees are mysteriously disappearing in many parts of the world. Most people don’t know about this problem. It is called “colony collapse disorder” (CCD). Some North American beekeepers lost 80% of their hives from 2006-2008. Bees in Italy and Australia are disappearing too.

The disappearance of the honeybee is a serious problem. Can you imagine never eating another blueberry? What about almonds and cherries? Without honeybees food prices will skyrocket. The poorest people always suffer the worst when there is a lack of food.

This problem affects other foods besides fresh produce. Imagine losing your favourite ice cream! Haagen Daaz is a famous ice cream company. Many of their flavours rely on the hard working honeybee. In 2008, Haagen Daaz began raising money for CCD. They also funded a garden at the University of California called The Haven. This garden helps raise awareness about the disappearing honeybee and teaches visitors how to plant for pollinators.

Donating money to research is the most important thing humans can do to save the honeybee. Some scientists blame CCD on climate change. Others think pesticides are killing the bees. Commercial bee migration may also cause CCD. Beekeepers transport their hives from place to place in order to pollinate plants year round.

https://www.englishclub.com/reading/environment/honeybee.htm