Albatross and petrels skim close to the water as they circle - riding the currents of air flowing over ship and the waves, following us for days on end, dipping down to grab their prey from the water and only very rarely setting down on it to rest. They are the kind of birds you almost think of as mythical if you have not seen them yourself. Until recently, if they survived their first year, these birds often lived long lives - albatross have been known to reach over 50 years of age.

Now, they face threats from man as well as nature. Longline and gill net fishing kills thousands each year. Others choke on floating plastic rubbish they mistake for food. According to Birdlife, 19 out 21 species of albatrosses face extinction, and their slow reproductive cycle (they lay just one egg and some larger species only breed every second year) makes it difficult for them to recover. Become an Ocean Defender to help.

Bird factoids:

•Wandering albatross will sometimes fly right around the globe searching for food.

•Parent wandering albatross convert food into an oily substance that they can store it in their stomach. This way they can travel far from their chick in search of food - distances up to 3,200km (1,988 mi) have been recorded - in search of food. The chicks can eat up to 1.8kg (4 lb) of this regurgitated substance in one meal.

•Great albatross (such as the wandering albatross) do not breed until their ninth or tenth year, and only lay one egg at time.

•All species of albatross normally mate for life with elaborate courtship dances.

•Maritime legend has it that albatross are the reincarnated souls of fellow sailors. It is considered unlucky to kill, or (by some) even curse them.

•Light-mantled sooties are one of the four species of albatross that gathers on South Georgia Island to breed. The call out specifically to their mate when they see it fly overhead, ignoring other birds.

•Albatross prefer to fly in a nice stiff wind - if it slacks off too much they'll often land in the water to wait for it to pick up again.

•Luckily the Southern Ocean is a pretty windy place.

Disclaimer: Although many of us have become enthusiastic bird watchers on this trip, none of us are bird experts. The photographers have done the best they could to identify each bird using the reference books at hand. If you spot one that you think is not labelled correctly, please leave us a comment.•