A lonely and renegade pigeon must abandon his reluctance and join the other park residents to expose a corrupt official, stop construction of the mall and save the old fountain, before the end of Independence Day.

I love it

A lonely and renegade pigeon must abandon his reluctance... This reads too heavy handed to me. This is all gone once he joins the community. So all these words for not much big picture issues.

A pigeon must join forces with other park creatures to expose a corrupt official and save the beloved fountain.

We don’t need much more.

That’s compelling – the fountain is the birthplace of this renegade pigeon. This is your anchor, the park residents need the water and safety, your protag wants to save his birthplace, where everything was good (before he became a renegade). This is a believable reason why he would act to join the others now. I get the Independence Day reference, but in your OP that hit me from left field, that’s why I included “ground-breaking” so I can immediately envision something being destroyed to create new.

Use Richiev example along with these points to recreate your logline – you're getting there!

Take care.