3.Nc3 is less advantageous than 3.Nf3. Black can also choose the move order 1.f4 Nc6 2.Nf3 e5 (3.fxe5 g5) which avoids the Nc3 treatment.  

Edward Winter's fine research regarding the "Swiss Gambit" (see rukh's link above) should have been mentioned in the Kaissiber article. But while the symmetrical 1.f4 f5 deemed natural to the players of the 19th century, it has become very rare nowadays. Nothing which I'd like to study in depth. Maybe White can just play 2.d3 Nf6 3.Nf3 with a kind of delayed From 4.e4, avoiding Bg4 ideas. Or a normal Bird.

After 1.f4 f5 2.b3, 2...Nf6 3.Bb2 e6 looks like an improvement. Then I don't see any problems for Black.

Perhaps 4...h6 is the way for Black to go in that line, by analogy with 1.f4 e5 2.fxe5 Nc6 3.Nf3 g5 4.h3! which is White's only route to advantage in the colours reversed version (source: Kaissiber 36).

Here's the relevant article in Wikipedia which gives 1.f4 f5 2.e4 a mention:
http://en.wikipedia.org/wiki/Bird%27s_Opening

Some sources, particularly in the 1990s, tended to overestimate the strength of From's Gambit for Black, so perhaps that influences the recommendation of 1.f4 f5 2.e4. 

Since the tempo f2-f4 isn't particularly useful and White has played 1.f4 as opposed to the Staunton Gambit's 1.d4, I don't think it should objectively be good- probably somewhere in the region = to =+ with best play- but like the From proper it could score quite well OTB.

Yeah, but I'd always heard that 2. e4 was the way to go, and I hadn't studied the line at all before it came up in a blitz game, so I was trying to play it like From's Gambit reversed on my first attempt with no preparation. 

Then I looked it up afterward and saw that Taylor doesn't think that approach really works. So now I'm considering other options, or whether I want to try sticking with the gambit, anyway. 

I still need to read through the details of Taylor's recommended b3 approach, but that does seem potentially quiet and boring - not really my style.

So now that I'm playing the Bird regularly, I've started running into this response occasionally. 

Taylor's "Bird's Opening" book seems to think that the gambit approach (2. e4) is probably not quite sound. It can't be played exactly like From's Gambit with an extra tempo, because black can play Bg4 against the strongest lines, when white can't play f2-f3 to block it. I tried the gambit in a couple of blitz games anyway, and my opponents didn't know how to handle it well, so I did ok. But I don't know if I want to play that way in slow tournament games against stronger opposition.

What do the rest of you think? What's best for white after 1. f4 f5?