unuseless
A petrel is a small sea bird that begins with the word pet.
UnattractiveUglyUnevenUsefulUrgent (for urgent emergencies where it starts to rain?)Can't think of any others :)
umbrella bird
knock-kneed
horrifyin
Umbrella is a spring word. It begins with U.
That is just the name they came up with. There is no specific reason. It comes from a Latin word 'Umbra' and its meaning is shade or shaded
FLY
crane
Bee.
Ugly describes beauty. It begins with the letter u.
Snowflakes can be described as lightweight. The adjective begins with the letter l.