This little riff that repeats throughout the song, and it's from the C# major pentatonic scale.
[ Tab from: http://www.guitaretab.com/d/ducktails/288680.html ]
e|-6--4-----4-------4----------------4---------------------------------------|
B|-------6-----4h6-----4--------4h6-----4------------------------------------|
G|------------------------6--3-------------6--3---1h3--6--3--6---------------|
D|---------------------------------------------------------------------------|
A|---------------------------------------------------------------------------|
E|---------------------------------------------------------------------------|
