This is prompted by a close look at the recent ‘Australian Bird Guide’. With respect to head/neck features of the Australian Raven, this says:
<< obvious long throat hackles … forming a beard reaching upper breast, especially when expanded while calling.
Ad. … iris white with pale blue inner ring: Crown rather flat ; bill long and heavy; black bare skin on base of lower mandible extends back to the sides of the chin forming a gular pouch. >>
The illustrations seem to me to be quite good in showing the difference from the Little Raven (discussed in a second message), without creating unrealistic caricatures in order to bring out the differences. However there is an annotation:
<< bare rectangular skin patch on side of chin >>
A slightly greyish patch can just be discerned in the illustrations that might be intended to represent bare skin. I had not myself noticed this in birds in the field, so I went through a few photos. I found a couple where it can be seen,
but I believe it is generally obscured by feathers, so I wonder about its usefulness as a field mark. I would not myself describe it as ‘rectangular’.
The bills are good in ABG, showing the A Rav as slightly but distinctly thicker from the side. The Nicholas Day illustrations in HANZAB show the A Rav bills as longer, but no thicker than the Little Raven. Head shape is good though.
