Michelle - I'm right there with you!!! With help from BW, we have dropped that habitual 4am feed - but a month later, the wakings continue. Ian is not unhappy per se, he is loud, cooing, rolling about, making as much noise as possible. I can hear him 2 doors down with no baby monitor on. Occasionally he gets frustrated and starts to cry - or scream!
The room is pitch dark, so that doesn't seem to matter. What I want to know is, is there any way to STOP it of do they have to just work it out? I definitely don't rush in, but DS1 is almost always awakened by this, and sometimes we all start the day now at 5:30-6am becuase it goes on so long. Then the schedule for the whole day is completely screwed up.
Keep me posted if you find something that works!