Watch the Bird Song online guitar lesson by Jeff McErlain from Essentials: Chord Tone Soloing
The next chord to consider is the G major, and what's really cool here is the Bb chord (of course) has a Bb note in it. The G major is spelled G-B-D, so we now have a B natural. This is a very strong note to hit at this point and really makes a difference.
Same idea when we get the A7b13: The name is scary, but the chord is basically A7 (AC#E), so on that chord I hit the C# note, which differs from the parent sound of Dm. But once again, if you just look at the chord shapes on these you'll see I'm just playing off of those.