My dad is a native plant and butterfly expert these days. No joke, people interested in this hobby actually look to him for answers and help, he's the plant man! See here.
So what do you get for your Dad's birthday, a man who typically buys what he needs and doesn't like "dust collector" type things? And you've already taken him to the Houston Butterfly exhibit in the last year...
You make him a couple of butterfly feeders! After searching the net a bit and being somewhat inspired (but not as completely as you'd hoped)...it dawns on you...a budget-friendly fruit feeder much like the ones at the afore-mentioned exhibit.
What you need:
a plant stand, preferably one that will stick into the ground well (I found mine at Big Lots for $5-$7 a piece)
terra cotta pot saucer (find one that preferably will sit IN the plant stand just a bit, more stable)
spray paint (bright colors)
Here are a couple of great sites if you are interested (thankfully, I have the man mentioned above to help me out!)