Dr. McGowan says the only place he is aware of that has scientific accuracy on vocalizations is in the vocalization section on the Birds of the World site for American Crow. This is a subscription site so not everyone will have access. However we do mention in one of the lessons of this course about Birds of the World and give a discount coupon for it. The coupon code is meant for folks enrolled in the course. Here is just a small portion of that account: <Wide repertoire of calls. Anatomy of syrinx reveals 6 pairs of syringeal muscles (Chamberlain et al. 1968). Most common call, heard year-round, is caw, given 2–5 times in a bout (range 1–9; Thompson 1968a). Cawing is main type of vocalization for long-distance communication (Parr 1997), used when individuals are 0.5–1.0 km apart (Brown 1985c). Some of the calls listed below are variations of this basic call, brought about by varying the frequency, duration, interval duration between caws, and intensity of each caw within bouts (Brown 1985c , Parr 1997). Parr (Parr 1997) recognized 8 basic caw types used in long-distance vocal communication: Short Caw, Short-Medium Caw, Medium Caw, Long Caw, Harsh Caw, Ko , Ko-aw , and Two-Syllable Caw. ...>> <<...Double Short Caw. A series of caws delivered in pairs, so that interval within a pair is smaller than between pairs. Often associated with territorial bouts, Countercawing, directed out of the territory, and particularly with the beginning of chasing bouts. Function as call-to-arms vocalizations for family members (Parr 1997). Corresponds to Chamberlain and Cornwell's (Chamberlain and Cornwell 1971) Alert Call....>> Those are just a couple excerpts but subscribers to Birds of the World can see the full account. Birds of the World American Crow vocalizations