Crows are more of a pain than anything. Though if enough of them attack you, you will lose alot of health points. The first place you will meet the crows is on the outside patio on the second floor of the Mansion.
As you enter the patio you will hear the caws of the crows and you will see one of your STARS members "Forrest" laying dead on the patio floor. Depending on which Character you have chosen Forrest will have on him:

Jill = Bazooka and a Mansion Key

Chris = Ammo Clip and a Mansion Key

Oh by the way I should tell you about... naaa you'll find out

Back to the Crows, well they are a pain and it only takes a bullet to drop one or even a knife wound either way don't waste your ammo if you don't have too. Once you get your required items run, cause the Alfred Hitchcock "Birds" remake is about to happen.

The second area where you'll meet up with the Crows is in the Art Gallery on the first floor. Here you will find a set of Portraits. You will have to figure out the puzzle in order to get the "Wind Crest". If you perform this correctly you will be rewarded with the needed item. However if you press the wrong switches the Crows sitting on the overhead lights will attack you and you will have to run out of the Gallery very very fast.