The only Australian Drongo, it can be easily identified by its forked tale and glossy black plumage.
However it can be more difficult difficult to identify it by its call, as it is an accomplished mimic, and will incorporate parts of what it hears into its song.
It is also a very accomplished aeronautical acrobat, and will dive and swoop to catch insects on the wing providing an entertaining display if you get to see it.
If you think its name is a bit of an insult, think again. It had the name first. An Australian racehorse was named after it, which went on to be very unsuccessful, leading to the slang term for someone who is a little "slow".
They are definitely not a slow bird however. An African relative even fakes alarm calls to trick meerkats to drop their food (at which point the drongo swoops in to help itself).