@Batchpool I think the bird DOES have an elaborate back story, lol. Maybe it's a symbol, a subtle subconscious reminder to stay hydrated. The crews need to drink plenty of water, and the birds are placed in strategic locations to remind them of this.
Water is essential to life. Weyland corp employees need lots of it when adapting to new environments out in space/the colonies. Sometimes the colonists forget to drink lots of water, so Weyland corp uses visual stimuli in subtle ways that drive in the idea to "keep chugging away". The employees' minds are almost tricked into being more productive.
An automated message aboard the Prometheus vessel reminds its crew how important it is to drink plenty of water. "There is nothing in the desert, and no man needs nothing". Every bird needs water.
When plants are present in the workplace, workers can be up to 35% more productive. Weyland corp saw to it that there were plants present in Dr. Shaw's quarters. The mere image of a plant can alter subconscious emotional states without the employee's knowledge... Shaw was also given a healthy dose of visual stimuli that reminds her of Earth (to reduce risk of cabin fever/space madness). Also, the crew NEEDS to be "shown that time is still moving", or there's greater chance of space madness.
Vickers was unaware that setting up the Christmas tree was habitual for Janek & other pilots at that time. The rest of the crew hadn't been in space before. The image of the Christmas tree helps them get used to the idea of sleeping for so long, the loneliness of space, and being isolated from those back on Earth. Janek did this on previous tours. It's a ritualistic behaviour, from when humans first pushed further into space - almost standard protocol at that time. Pilots used Christmas trees as a symbol to motivate them when Christmas rolled around (humans became more used to long space voyages by Ripley's time).
The company sets up visual stimuli like this when they can, to remind the employees of home. Tricking the employees into being more productive is all part of perpetuating the company's secret goals... Even the drinking birds are part of their hidden agendas.
The drinking bird is something Weyland corp started placing everywhere when it was first establishing colonies. Cases of cabin fever/space madness can occur if these and other types of knick-knacks and decorations aren't present for people who aren't used to being in space. Space can be a lonely place, and they need things like this for decoration, and for other purposes. Especially when people come out of hypersleep for the first time. The screen in Vickers' cabin projected images of Earth to make her feel more at home. Vickers is one of the ones who can't live without all the comforts of home.
