Sforno on Deuteronomy 22:7/ספורנו על דברים כ״ב:ז׳

1למען ייטב לך והארכת ימים, in the matter of dispatching the mother bird before taking her chicks, we find some display of protective concern by the Torah for the preservation of the species, an effort not to destroy the seed of the birds of the field although they are הפקר, unclaimed property. In the example of the dispatch of the mother bird the Torah appears to teach us that even the display by us of concern for such totally unclaimed eggs or chicks is rewarded by the Creator with the party showing this empathy receiving dividends in this life and the principal (reward) in the world to come.