shiluach ha'kan

In the past few years I have seen advertisements offering people the opportunity to fulfill shiluach ha'kan.  I suspect the motivation here is the great weight the kabbalah assigns to this mitzvah.  Whenever you start talking segulos and kabbalah, people pay attention.  

The problem is that it's not a very easy mitzvah to fulfill.  First off, many if not most poskim hold there is no reason to do the mitzvah unless you want to collect the eggs or chicks.  The Chavos Ya'ir disagrees, and presumably if you want to do the mitzvah to be choshesh for that view, or because of the segulah, that purpose overrides the potential tzaar baalei chaim involved.  Still, it seems cruel to take the eggs or chicks for no purpose.  To avoid this problem R' Melamed in his Pninei Halacha suggests in this circumstance one can rely on the view of Chacham Tzvi who holds that there is a kiyum  in chasing away the mother even if one does not take the chicks or eggs.    

The mitzvah only applies to kosher birds, and only applies when the chicks are still too young to fly, and only applies when the mother bird, not the father, is on the nest.  There are birds where the mother and father alternate sitting on the nest at different times.  Good luck to you in being able to tell the difference.

Finally, and most critically, the nest has to be in the wild, ownerless.  A lot of times people discover a nest somewhere on their property, either tucked under a section of roof on a porch, or under an air conditioning unit, or something like that.  A soon as the mother bird flies off that nest for a moment, there is a potential kinyan chatzeir that should kick in and make the nest one's own, no longer in the wild.  Some hold that if you catch the birds in the process of building the nest before it is complete, you can make a tnai in advance that prevents the kinyan chatzeir from being chal.  Others go further and argue that since one does not really want to own a bird's nest, even without a tnai the kinyan is not chal.  Perhaps you can be mafkir the nest after the fact.  R' Shlomo Zalman Auerbach is not too happy with these solutions.