Why a carrier's listed air group may omit its Walrus

Were Walrus support aircraft counted in a carrier's normal air-group total?

Usually no; a Walrus could be carried in addition to the aircraft included in the published air-group figure.

Royal Navy carriers sometimes embarked Walrus support aircraft in addition to their listed operational squadrons. Those aircraft were often omitted from published air-group totals. A nominal complement can therefore understate the number of aircraft physically aboard when ancillary types are excluded. Comparisons between carriers need to distinguish the counted combat air group from support aircraft carried outside that figure.