The finger picking pattern is up to you to figure out. 
I don't know how to explain it well enough. 
That's the key, though. 
Let your ears teach your fingers 
Just like they taught your tongue how to talk 
A little bird come sit upon my window sill. 
He sat there all thru the fallin' rain 
As I watched that little bird upon my window sill 
I saw my thoughts of you go by again 
CHORUS: A picture of my face on the pane 
Is it tears 
I see or is it rain? 
I remember how we talked before we said goodbye 
Too young to know the world outside our door 
We laughed and said our love was free 
Like birds that fly the wind 
Till the rain today made me think of you once more 
I've no regrets about the past 
I see how young we were 
When the world was love and time was but a thought 
Many things go many ways and many times but once 
Till our lives are past and that love is but a thought 
CHORUS As my thoughts go tumblin' back 
I wonder how you look 
I wonder if you've seen that little bird 
I wonder if he's sat upon your window sill 
I wonder if you'll ever hear these words