One is a crop of the other, yes. I've had 2 or 3 saying a similar thing about photo #1 (which indeed is a crop). I'm personally quite tickled at how this bird photographs in the winter landscape, it's surreal.
My monopod won't break the bank, it's about as cheap as they come: OPUS OT-S10M (huge price tag of $30 US). The ball head is a Manfrotto 486, about $60 US. Photographyreview doesn't have much good to say about it but it works for me: http://www.photographyreview.com/psc...3_3134crx.aspx
This combo is cheap, lightweight, and if I leave it behind at a shoot I won't kick myself too hard, so all those are advantages to me.
As for the bright light, it would bea puzzle to me why you couldn't get enough light with your F/4 (without the extender) as I had no trouble the other day with my F4 lens. Unless it's all the white snow? It's been extremely clear the past few days, just cold.