Most of the glyphs of this type are easy to identify. Not only have they a front view but they have also other identifiable characteristics. Therefore I have as GD11 sorted Aa5-28, Ab3-28 and Ab7-50:

The head is enough for identification. When the head is alien the rest may be enough for identification, e.g. Ab4-37:

Alien heads are sometimes looking as if the bird belonged to another species, e.g. Ab7-69 and Ab8-13:

But they belong under GD11 anyhow. One exception is GD77-birds, viz. Aa5-9, Ab6-37 and Ab7-29:

The reason is rather obvious: not only is the head alien but also the wings and all the rest.

There is a problem when a GD11 type of beak exists on a totally different type of glyph, e.g. Ab4-65 (GD17):

Cfr the left - from us seen - top 'flipper'. Such an easily missed sign is not reason enough to sort a glyph under GD11.

Similarly, what possibly is an 'undulating wing' - a sign of a variant of GD11 - may exist in other types of glyphs, e.g. Aa5-72 and Ab7-84 (GD63), without that being enough reason to sort them under G11 too:

The hyperlinks to GD54 and GD58 have been inserted because these types of glyphs are located there: