Wow, a hawk in your front yard, that is a big bird with big talons.
My suggestion is to get a protective hat, while the fledgeling are in the nest. When they are gone, remove any hint of the nest so they will not come back next spring.

Hard hat or bike hat for the duration and as west gardener said, get rid of the nest once they are out and use the water hose if they try to build again.
I am not going to gripe again about our neighborhood mockingbird.

I talked with Joann about this last night, and she said that in a similar situation, she just used her umbrella as a shield

That's a super idea, lilo. I could use one of these during nesting season around here. lol
See link,

Here is a link that might be useful:

West Gardener - I love it!

If hawk is really dangerous then you should try to find its solution soon. You can contact to wildlife.

train it to guard your home while you are not at home! This will be better than any security system!