It's the longest mural he's painted in Wanganui, but not the tallest.
"When you do street art, there's so much to take into account, and a lot you can't control. Like the material you're painting on, the weather, and the reaction of the public.
"You're not painting in your own studio; you're out there for everyone to see."
Mr Gardiner has a particular liking for painting modern designs on historic buildings, especially brick.
"Brick can be quite challenging to paint on, it has all those crevices you have to fill in - and it absorbs a lot of paint."
The bird mural was designed by Mr Gardiner, but some local students helped him paint it.
Mr Gardiner, based at Pukawa Bay near Turangi, is the first annual artist-in-residence at Whanganui Arts @ The Centre.
He is having an exhibition at Space Gallery later this month. Opening on March 28, it is titled Drawing Number II, Love Lust and Cultural Hibernation, and features a variety of media.