The second edition of The Sibley Guide to Birds goes on sale on March 11, 2014. Birdwatching has an article and interview with David Sibley about the new Sibley Guide at First look: David Sibley describes changes to look for in his revised Guide to Birds – BirdWatching. The article states:
According to the publisher, almost every aspect of the book has undergone a remarkable makeover. Dozens of species have been added, most paintings have been revised, and hundreds of new paintings have been created. Maps have been updated, fonts have been tweaked, illustrations enlarged.
The Amazon description says
The second edition offers a wealth of improvements and updates:
• All illustrations reproduced 15 to 20 percent larger for better detail.
• Includes nearly 7,000 paintings digitally remastered from original art for enhanced print quality.
• Expanded text includes habitat information and voice description for every species and more tips on finding birds in the field.
• More than 600 new paintings, including illustrations of 115 rare species and additional paintings of common species and regional populations.
• More than 700 updated maps of ranges, showing winter, summer, year-round, migration, and rare ranges.
• 85 bird family pages now cross-referenced to species accounts.
• Revised taxonomic order and most current common names for every species.