Just a thought, for an Owl instead of red or green they make FLICKER LED's in a YELLOW GOLD, so no circuit is needed just a resistor like any ordinary LED.
Only difference is they flicker!
I purchased a 100 pack for $5 or so on Ebay.
Be sure to copy the Voltages ratings of the LED's so when you use the resistor calculator you get the correct resistors for your LED's and keep a copy (I put mine in the bag of LED's)
Ebay is a great source for LED's Radio Shack has a very limited supply (great in a pinch if you need them fast)
See if the vendor has your resistors at the same time