I am sitting in a restaurant in Bruges, Belgium which has two little canaries locked in a small cage. The birds look very unhealthy and traumatized. Furthermore there are missing feathers all over their little bodies. What can i (realistically and legally) do to help these poor creatures?
In most cases you have 3 options/strategies to follow :
Inform and support the owner
Inform law enforcement like police or governmental animal welfare authorities or veterinarians
Inform animal rights organisations
In my opinion, one should always try option one first.
Most times the owner wants to care for their animals, but doesn't know how, or needs help following the rules they already know. For example, a dog who is not taken for walks due to a lack of time or misbehavior of the dog.
Sometimes the owner hasn't chosen the animals themselves. They may have been a gift or left behind by children moving out of their parents' home. In those cases, chances are high the owner would like to give them a new home.
Only rarely does the owner actually want to do the animal harm.
In your case, it is important to understand why the owner has this birds. Should they attract people to the restaurant? Then you can make a point that they would be attracting more, if they were looking healthy and singing happily. Are they too much work for the owner? Then you could give them information about how to find a new home for them.
It is easier if you or someone with the same concerns speaks the same language as the owner.
Only if the owners do not want to talk to you, should you mention option 2 and 3 to them.
For option 2, you should inform yourself about laws like minimum space for birds, if there is a law about healthcare, and so on.
For option 3, you could ask the organisation about the laws, your options, and if the owner is actually known for misbehavior.
Buying the birds without any information about the owner is not an option. In the worst case they buy new ones the next day and don't change anything.
(If you want help with "How to talk with the owner," interpersonal.SE is a good resource.)