A pigeon settled on my balcony. What should I do?
You cannot predict the future of the bird or take responsibility for it. Also, the bird may nest on your balcony temporary (for breeding) rather than permanently. If the bird does not harm you, then you should let it nest. 

If the hostess (landlord) disapproves of the bird, they should remove it. It is not your responsibility to make modifications to the property of the landlord or hinder the landlord in the maintenance of their property. Instead, if you think the bird will damage the property, it is your duty (as a tenant) to report this to the landlord. 

In summary, the bird is not your responsibility (karma) and the external structural problems of the apartment is not your responsibility (karma). 

The problem is the bird's karma &amp; you should not interfere with the bird's karma.