After 1.e4 e5 2.Nf3 Nc6 3.Bb5 Nd4 4.Nxd4 (considered the most critical test, though 4.Ba4 is a simple and solid approach) 4...exd4 5.O-O (theory's main line), Black has a wide range of choices. These include the "Historical" Bird line 5...Bc5 (my own preference and the one favored by current theory); the "Modern" 5...c6 (to be followed by either 6...Nf6 or an immediate 6...d5!? break); Blackburne's 5...g6 (which Mackenzie calls the "Red Bull" because it seems to provoke White to charge); and a variety of minor variants (including 5...Ne7 and the surprising 5...h5!? -- which was occasionally used by Bird himself and treated favorably by IM John Watson). The defense is such a "rare bird" among the chess elite that the consensus on how best to play it changes with practically every major GM encounter. What this means is that Bird's Defense remains a rich territory for opening exploration and innovation.
I have tried to organize the bibliography in reverse chronology, to show the development of theory. I have listed the few available web sources first since these are most likely to be used by readers. As always, I am happy to receive corrections or additions in the comments.
Mackenzie, Dana (2008). "Bird by Bird, Part 3A," "Bird by Bird, Part 2," and "Bird by Bird."
In a series of blog posts, the author and ChessLectures.com instructor discusses his Bird repertoire with illustrations from his games. He makes a good case for Blackburne's favorite 5...g6 in the main line and offers some fun and interesting illustrations of enterprising Black strategy.
There are only 432 games in the database, but the chessgames presentation provides easy access on the web. Those interested in more games would do well to check the main Game Collections and Databases.
Anderssen - Lange, Breslau 1859 at YouTube
Spanish language presentation on the classic Bird game.
Herb, Pascal (2006). La defense Bird de l'Espagnole at Andrei Sokolov's "Les Echecs en noir et blanc."
A free resource that gives a useful analytic overview of the Bird. But the latest game reference is 1987, so you know the original work is not as recent as the 2006 date would suggest.
Watson, John (2004). "Ruy Lopez, Bird Defense" at JeremySilman.com
A very interesting discussion by the noted opening theorist of Bird's 5...h5!? idea, in response to a reader's question. Watson thinks it is quite interesting and playable.
Basalla, Bob (2004?). Oldies but not Moldies (PDF) at Vivacity Chess Center
A move-by-move discussion of Anderssen - Lange, Breslau 1859, which is not the first to mention that Anderssen missed 10.Qe1!
rlbrd-pg.zip (1996) via ftp at the Pitt Archives
A zipped .pgn file of Ruy Lopez. Bird's Defense games to download via ftp.
Books and Articles
The following materials are listed in reversed chronological order to highlight changes in Bird theory. A more thorough treatment might include the classic opening manuals (Euwe and Keres) and ECO, and I may eventually add them.
Flear, Glenn (2008). "L'Oiseau." Dangerous Weapons, 1.e4 e5: Dazzle Your Opponents in the Open Games. Edited and written by John Emms, Glenn Flear, and Andrew Greet. Everyman Chess, pp. 85-102.
Flear's discussion of "L'Oiseau" (French for "bird") offers a contemporary and coherent repertoire built around the currently favored 5...Bc5 line. While Flear's earlier coverage of the line in Offbeat Spanish seemed a bit more encouraging for White, here he takes the Black side (as he himself has done quite often), offering interesting games and finding solutions to typical Black problems. One interesting line following 5...Bc5 is to play 6.d3 c6 7.Bc4 d5! 8.exd5 cxd5 9.Bb5+ Kf8!? when White's Bishop is poorly placed, Black's doubled pawns control all the central squares, and Black's King is safer at f8 than White's is in his castle.
The 5...Bc5 development scheme is not without its problems, and Flear does not ignore them. For example, 4.Nxd4 exd4 5.Bc4 prevents the normal development by 5...Bc5 due to 6.Bxf7+! and Qh5+. And there is no easy solution in 5...Nf6 due to 6.O-O d5 7.exd5 Nxd5 8.Qh5! with advantage to White. To solve this problem, Flear suggests 5...h5!? which keeps the Queen out of the critical h5 square so that Black can return to his preferred scheme of development by Bc5, c6, and d5. This is an interesting idea, which Bird himself employed on occasion. Flear also recommends meeting the difficult line 5.O-O Bc5 6.d3 c6 7.Ba4 (intending f4-f5) with 7...d6 8.f4 f5! to block White's f-pawn's advance. This scheme has worked in several games, even though the Black King may have to flee to the queenside.
Flear presents a very enterprising and coherent repertoire for Black. Among the games he examines are Fressinet - Fontaine, French Championship 2005; Short - Kupreichik, Hastings 1981-1982; Zulfugarli - Najer, 1999; Kalod - Jirka, Brno 2006; Morozevich - Najer, Moscow 1992; Benjamin - Flear, Hungary 1987; Hossain - Al Rakib Abdulla, Dhaka 2006; Davies - Lorenz, Berlin 1987; Huebner - Nunn, Brussels 1986; Beliavsky - Tseshkovsky, USSR 1986; Savon - Malaniuk, Warsaw 1992; Ljubojevic - Salov, Rotterdam 1989; Sigurjonnson - Kupreichik, Winnipeg 1986; Novik - Meister, USSR 1991; Aldama - Mamedyarov, Bled 2002; and Simacek - Jirka, Olomouc 2001. Even if you are not so taken with the 5...Bc5 lines, the Dangerous Weapons 1.e4 e5 book is worth having for its own sake (as I wrote in a review back in April).
Greet, Andrew (2007). Play the Ruy Lopez. Everyman Chess, 82-102.
In an interesting repertoire book built around the Worrall Attack (5.Qe2 in the main line Lopez), Greet covers sidelines like the Bird, offering basically the same repertoire as Karpov and Lane before him with 4.Nxd4 exd4 5.O-O Bc5 6.d3 c6 7.Ba4 Ne7?! 8.f4!
Lane, Gary (2005). "Rare Third Moves." The Ruy Lopez Explained. Sterling Publishing, 10-14.
Focusing on Horvath - Pamkilpel, Berlin 1997, Lane offers more detailed treatment than Karpov does of 1.e4 e5 2.Nf3 Nc6 3.Bb5 Nd4 4.Nxd4 exd4 5.O-O Bc5 6.d3 c6 7.Ba4 Ne7?! 8.f4! with consideration of Black's other replies along the way.
In an article ostensibly about Keith McLaughlin's victory in the 2002/2003 British Correspondence Chess Association championship (and including a number of games besides McLaughlin's), editor Tait devotes 10 densely annotated pages analyzing McLaughlin's incredible success (+8 =7 -2 as Black) with the main "Modern" Bird line 5...c6 6.Bc4 Nf6. McLaughlin typically plays right into Matanovic - Gliksman 1967 with 7.Re1 d6 8.c3 Ng4 9.h3 Ne5 10.d3 Nxc4 11.dxc4 dxc3 12.Nxc3 Be7 13.Bf4 O-O and has actually won from this position as Black (+2 =3 in fact). This is essential reading for anyone who would like to revive the Modern line, which is much maligned in the rest of the literature (as Tait neatly reviews). No other lines of the Bird are covered, though Tait mentions the game M. Read - Skotorenko in Correspondence Chess #142 as showing "Black's troubles" in the 5...Bc5 line.
As part of his discussion of the Ruy Lopez for White (focusing the repertoire around the safe Exchange Variation), Kaufman gives only the second Kasparov - Khalifman, Moscow 2002 game to guide White play. He also mentions analysis by Emms arguing for a White edge after 5...Bc5 6.d3 c6 7.Ba4 d6 8.Bb3!
Khalifman, Alexander (2003). Opening for White According to Anand 1.e4, Volume 1. Chess Stars.
I have not seen this yet, but Khalifman's series is superb, so he likely offers a very thorough analysis from White's perspective on the Bird. From what I gather, one line he recommends is 1.e4 e5 2.Nf3 Nc6 3.Bb5 Nd4 4.Nxd4 exd4 5.O-O Bc5 6.Bc4, threatening Bxf7+.
Shaw, John (2003). Starting Out: The Ruy Lopez. Everyman Chess.
Shaw practically ignores the Bird completely to devote pages to the Berlin and Schliemann.
Van der Tak, A. C. (2002). "Twice is once too often!" New in Chess Yearbook #64. 104-109.
The article's title describes how Alexander Khalifman twice used the Bird Variation as a surprise weapon against Garry Kasparov in their mini-match at the Grand Prix in Moscow 2002, choosing the very "Modern" line 1.e4 e5 2.Nf3 Nc6 3.Bb5 Nd4 4.Nxd4 exd4 5.O-O c6 6.Bc4 d5!? 7.exd5 cxd5 8.Bb5 Bd7 9.Re1+ Ne7. In their first game, Kasparov used 10.a4 and Khalifman had no trouble equalizing, though the champion sacrificed the Exchange for attacking chances and tested him in a long queen ending. In their second game, though, Kasparov and his team came up with 10.c4!N which led to a Black debacle in 23 moves. Van der Tak examines these games and 15 others with the Modern 5...c6 line -- including ones where Black tries instead 6.Bc4 Nf6 (preferred by theory) and the unusual 6.Bc4 Ne7!? 7.Re1! (7.d3 d5!) Ng6!?
Flear, Glenn (2000). "Bird's Defence." Offbeat Spanish: Meeting the Spanish without 3...a6. Everyman, 94-108.
Flear offers more of a White perspective here, analyzing several games, most of which feature the 5...Bc5 line. In fact, Flear practically ignores all of Black's other main systems, which makes his coverage less than ideal for White preparation. Following Karpov (see below), he focuses on Kamsky - Ivanchuk, Tilburg 1990, though he also takes note of Novik - Meister, USSR 1991, which is ECO's main line, though he writes that "the whole set-up looks somehow artificial and White players should be able to find something." Other interesting games that receive mention include Dvoiris - Meister, Russia 1992; Geller - Klaman, Tblisi 1949; Reti - Spielmann, Budapest 1913-1914; and Romanishin - Malaniuk, Tblisi 1986.
Emms, John (1999). Easy Guide to the Ruy Lopez. Everyman.
I have not seen this book.
Taulbut, Shaun. (1996). Understanding the Spanish. Batsford, 136-137.
Like Lane (see below), Taulbut offers a safe and solid repertoire choice for White with 4.Ba4 and uses the game Short - Kupreichik, Hastings 1981-1982 as his sole illustration.
Karpov, Anatoly (1994). Winning with the Spanish. Trans. John Sugden. Batsford, 150-159.
The former champion offers careful analytic coverage favorable to White, focusing on the game Kamsky - Ivanchuk, Tilburg 1990, which helped to establish the line 5.O-O Bc5 6.d3 c6 7.Ba4 Ne7?! 8.f4! as a critical test for Black. Other games discussed include Oll - Guseinov, USSR 1989; Ljubojevic - Salov, Rotterdam 1989; Kindermann - Tatai, Budapest 1987; Kindermann - Lorenz, West Berlin 1987; Spassky - Barua, NY 1987; Blatny - Malaniuk, Warsaw 1989; and Romanishin - Balashov, Erevan 1986.
Rotariu, Gheorghe and Pietro Cimmino (1992). The Bird Variation in the Ruy Lopez. S1 Editrice SRL.
Before databases, books like this one were invaluable. And they are still useful for their attempt at comprehensive coverage, especially when newer opening books tend to offer a limited repertoire rather than an overview. Like the Leach pamphlet (see below), the book is very well organized and there are some useful notes, though most of the illustrative games receive no annotations whatsoever. It includes excellent indexes to variations and players and therefore makes a very useful reference tool.
Suetin, Alexei (1992). The Complete Spanish. Trans. Malcolm Gesthuysen. Batsford, pp. 45-50.
Suetin provides thorough analytic treatment of the main lines, focusing on 5...c6 and 5...Bc5. He favors 5...Bc5, which he says "appears to offer quite good prospects" for Black. The move 5...g6 is rejected based on the game Capablanca - Blackburne, St. Petersburg 1914 (rather than Tarrasch - Blackburne, St. Petersburg which is the focus of subsequent writers). The most recent game citation is 1989. Chief game examples include Dvoiris - Balashov, USSR 1986; Anand - Tseshkovsky, Calcutta 1986; and Beliavsky - Tsechkovsky, USSR 1986.
Lane, Gary (1992). The Ruy Lopez for the Tournament Player. Batsford, 215-221.
Lane says the Bird is quite sound and suggests White try "to seek a small edge" with the practical 4.Ba4, using the games Mokry - Agdestein, Gausdal 1987 and Georgiev - Hector, Haifa 1989 to illustrate. He also offers the games Short - Ivanchuk, Linares 1989 and Zaichik - Kupreichik, Leningrad 1989 to illustrate the 4.Nxd4 exd4 main line.
Yudovich, Mikhail (1986). Spanish without ...a6. Trans. Eric Schiller. Collier Books, pp. 60-70.
Yudovich offers complete analytic coverage with a generally positive assessment of Black's chances, especially in the 5...c6 line with an early d5. He is less persuaded by 5...g6 or 5...Bc5, though he thinks even here White only gets the "slight edge" that is his destiny.
Haag, Russ (1986). "Theoretical Novelties: Cracking Bird's Defense to the Ruy Lopez." Chess International, July - August, p. 6.
In a packed, one-page article focused on the line 1.e4 e5 2.Nf3 Nc6 3.Bb5 Nd4 4.Nxd4 exd4 5.O-O c6 6.Bc4 Nf6 7.Re1 d6 8.c3 Ng4 9.h3 Ne5 10.d3 Nxc4 11.dxc4 dxc3 12.Nxc3 Be7 13.Bf4 O-O 14.Qd3! Be6 15.Rad1 Re8 (with careful consideration of main alternatives along the way), correspondence master Haag considers two of his recent games from the White side which help to establish that White indeed has an advantage against this old main line.
Leach, Colin (1985). Ruy Lopez Bird's Defence. Caissa Books.
This 70-page pamphlet offers a complete analytic treatment, presenting about 150 lightly annotated games and some original analysis in 16 sections that cover all reasonable lines after 1.e4 e5 2.Nf3 Nc6 3.Bb5 Nd4. It gives about equal treatment to 4.Nxd4 exd4 5.O-O c6 and 5...Bc5. As with his pamphlet on the Bishop's Opening, Leach covers some lines neglected by later writers, has a complete player index, and organizes the material well. For the most part, though, the games it contains can probably be found in most databases and the original annotations discovered with a computer. It does offer some useful original analysis, however, of the tactical "Modern" lines in a way that expands on McCormick and Soltis and helps to put that line to rest.
Soltis, Andy and Gene H. McCormick (1981). Bird's Defense to the Ruy Lopez. McFarland.
Probably the best book-length treatment of the opening to date, featuring some ground-breaking historical research. This book is worth having for the 52-page introductory section featuring a biography ("The Genius of Henry Bird") and collection of Bird's games with the opening, given with historical introductions and some contemporary notes. The analysis, however, is limited by the number of games that were available in 1981. Where it is most valuable is in analyzing the tricky "Modern" line 1.e4 e5 2.Nf3 Nc6 3.Bb5 Nd4 4.Nxd4 exd4 5.O-O c6 6.Bc4 Nf6 7.Re1 d6 8. c3 Ng4 9.h3 Ne5 10.Bf1 d3 11.f4 Qb6+, as in the game Ujtuman - Lein, Sochi 1965. While Schwarz cites analysis that seems to refute Black's play (pointing out 11.Re3! and 12.Kh2! as improvements), McCormick and Soltis provide some interesting ideas, including 11.Re3 g5!? and 12.Kh2 h5 13.fxe5 Bg4 14.hxg4 hxg4+ 15.Kg3 when 15...Qb8 appears to bolster Black's attack. However, as they discuss (and Schwarz had shown), White has a simple way of handling the position, as demonstrated in Matanovic - Gliksman, Kraljevo/Zagreb 1967, which continued 10.d3! Nxc4 11.dxc4 dxc3 12.Nxc3 Be7 13.Bf4 O-O 14.Qd3! (Schwarz mistakenly recommended 14.Qd2?! when Be6! 15.b3 Bf6! =) and White has a solid edge due to his pressure against the d6-pawn and possibilities of sacrificing a Knight at d5. Haag (see above) later was among those to prove White's positional advantage rather conclusively, and the entire variation disappeared from GM practice before a final verdict was ever rendered on the more tactical lines that follow 10.Bf1.
Schwarz, Rolf (1970). "Die Bird-Verteidigung." Spanisch II, Band 21. Verlag Das Schach Archiv of Hamburg, pp. 127-153.
This is a Classic German language opening series which covers a lot of territory. The Bird section is broken up into 13 mini-chapters on different variations, with 14 illustrative games (some of which supplement the analysis by discussing lines they do not cover). Schwarz focuses on and begins with the "Modern" 5.O-O c6 lines (which alone take up the first 8 sections). He then devotes a section each to 5...Ne7, 5...Bc5, 5...g6, 5.d3, and third move alternatives for White. Noted games include Ujtuman - Lein, Sochi 1965; Matulovic - Iliewski, Skopje 1968; Geller - Kholmov, USSR 1949; Suetin - Tolush, USSR 1950; Smyslov - Yudovich, Leningrad 1947; Smyslov - Lutikov, USSR 1960; and Michel - Rossetto, Mar del Plata 1947.
According to Pete Tamburro, Gruenfeld cites v. Scheve-Spielmann, Ostend, 1907; Anderssen-Blackburne, Vienna, 1873; Fine in PCO; Boleslavski-Ravinski, Moscow, 1944; Smyslov-Aaltorzev, Moscow, 1946; and Geller-Kholmov, Moscow, 1949.
Please post additions or corrections in the comments section and I will add them.