big brother
哥 centers on the idea of an older male sibling: a big brother. It is a less common variant of 兄, used in some names and compounds.
哥 is a duplication of 可, likely used as a phonetic loan or variant for 'elder brother.' The exact historical development is uncertain.
Two 可 stacked like two brothers: the top one is the big brother watching over the younger one below.
For カ, imagine a big brother driving a car: car -> カ, and he's taking his younger sibling for a ride.
common myna (Acridotheres tristis); Indian myna; common mynah; Indian mynah
crested myna (Acridotheres cristatellus); crested mynah
Gelaohui (secret Chinese society of the late Qing dynasty)
green-winged macaw (Ara chloropterus); red-and-green macaw; scarlet macaw
Indian rose-ringed parakeet (Psittacula krameri manillensis); ring-necked parakeet