In New Zealand we have four species of bumblebees.
According to the NZ Bumblebee Conservation Trust, Bumblebees carry up to 90% of their body weight in food and the level of activity required to fly is so great they are only ever 40 minutes away from starvation. They can reach ground speeds up to 54 kms per hour.
Bumblebees perform buzz pollination, also known as sonication, which involves applying vibration to shake pollen free from the tubes in which its held.
From Biobees: 'Bumblebees are members of the same family of bees as honeybees, the Apidae, and neither honeybees nor bumblebees are native to New Zealand. Bumblebee species were introduced from the United Kingdom for the pollination of red clover at the turn of the 20th century, with four species becoming established. Prior to that, all clover seed had to be imported from the UK at large cost, as New Zealand had no native species that would readily pollinate clover flowers. It was the first instance of a species imported solely for its pollination services.'
Nowadays bumblebees are primarily used for the large scale greenhouse pollination of tomato plants, whose pollen is held inside pollen tubes that prevent straightforward collection and thus require buzz pollination.
In winter, female bumblebee queens remain, hiding themselves under leaf litter, in old mouse holes, or under compost in open bins. Anywhere there's a cosy cavity, away from the most severe frosts will do. Have a look in your space - are there any cavities? Could you provide one?
You could create a small gap in between a few stacked bricks or leave a pile of jute bags. As long as there's no overheating by direct sunshine in summer, no flooding during downpours or excess shade, frost or cold wind, a bumblebee queen will be happy.
As always, make sure to have early spring-flowering plant species in your garden.
Here is a link to building your own bumblebee hotel.