I have to agree with Chilly Billy, crows are my friends. They are very territorial and if a hawk comes near their territory they cry out to the other crws so that they can mount a joint defense--crows are one of the only bird species that work as a team. They will often kill a hawk that wanders to close. When my chicks hear certain crow calls they all run for cover! I haven't figured out which call it is yet (crows also have an extensive "vocabulary", 32 "words", I think). Anyway, they were more likely protecting their nest than thinking about killing the chicks.
As for the noise, I have that problem with all birds around nesting time. Two years ago there was this one idiot that built its nest in a tree outside my bathroom window. In the early (5-9 am) morning, b/c of the way the sun was shining on the window, the windowmust have looked like a mirroe. So, seeing another male (his reflection) so close to the nest, he insisted on screaming and dive bombing the window for hours. After a few days, when I figured out what the nut was doing, I hung a dark towel inside the window. Ah, peace at last!
As for the noise, I have that problem with all birds around nesting time. Two years ago there was this one idiot that built its nest in a tree outside my bathroom window. In the early (5-9 am) morning, b/c of the way the sun was shining on the window, the windowmust have looked like a mirroe. So, seeing another male (his reflection) so close to the nest, he insisted on screaming and dive bombing the window for hours. After a few days, when I figured out what the nut was doing, I hung a dark towel inside the window. Ah, peace at last!