Swift language (and birds)

Swift is open source and why you should care - O'Reilly Media
"An initial look at Apple's open source Swift language."

"In Swift, values are not allowed to be null. (!)

Variables in Swift are only allowed to be nil, if they're not optional variables.
An optional variable is declared with a question mark after its type"

swifts is species of small bird
Apodiformes - Hummingbirds and Swifts | Wildlife Journal Junior