Sunwing is a children's book written in 1999 by Canadian author Kenneth Oppel. It is the second book in the Silverwing series, preceded by Silverwing and succeeded by Firewing.
Shade, Marina and their friends in the Silverwing colony fly in the middle of the winter in hopes of finding Shade's father Cassiel. The bats find a Human building, and fly inside, thinking that Cassiel might be there. Inside, they find an artificial forest filled with many other bats. The Silverwings discover that they cannot escape and that Cassiel is not there. Panic arises when several bats disappear, including Shade's friend, Chinook. Shade and Marina escape by way of a river that runs through the forest and find another artificial forest, this one filled with owls.
Upon arriving in the other dome, Shade and Marina befriend Orestes, a boreal owl and the son of the owl king. Owls begin to disappear as well and Shade discovers that humans are experimenting on them. Shade has a run-in with Goth whom he is surprised to find alive, let alone in the same facility. Eventually Shade, Orestes and Goth are captured by the humans while Marina escapes. The humans shave a patch of Shade's fur, attach a disc to his belly and a stud to his ear, and put him in an airplane flying south. Inside he finds a Chinook who is confused about the purpose of the metal discs and studs.
Marina is clinging to the plane, but is soon thrown off by the turbulence. She breaks Frieda, Ariel and two other Silverwings out of the building. They then encounter a Graywing colony and learn that the owls have laid siege to Hibernaculum, believing the actions of Goth and Throbb to have been perpetrated by Silverwings. Devastated at this news, they decide to recruit additional helpers in Bridge City, which is possibly the only safe haven left for bats.
In the plane, Shade and Chinook escape to see that they are on the outskirts of a city beside a massive jungle, what Shade realizes to be Goth's homeland. They see that the other bats wearing the earpiece are induced to fly into a target building. Shade reels back when he sees that the metal discs explode when the bats carrying them reach the target. Shade and Chinook are able to free themselves of the discs and find a group of survivors who are hiding from Goth's species, the Vampyrum spectrum. Shade begins to learn more about them from a weakened bat named Ishmael.
Goth, reaching his home in an ancient Mayan pyramid, is anointed king and told of a prophecy by his priest Voxzaco. According to the prophecy, if a hundred hearts are offered to their god Camazotz, the coming solar eclipse will last forever, allowing Zotz to rule both the Upperworld and Underworld. Meanwhile, the Silverwings make their way to Bridge City and hold a council of war about the rumoured threats to the bats. Northern rat king, Romulus (now estranged from Remus) agrees to help them. He puts them in touch with Cortez of the Southern rats who can access waterways to Central America.
Shade hastens to rescue his father, who they discover is now a captive of Goth's clan. On the way, both Chinook and the owl prince Orestes are captured by a small group of Vampyrum spectrum. While contemplating the loss of Chinook and Orestes, Shade notices something burrowing into Statue Haven and finds himself reunited with his mother and Marina. Shade, Marina, Ariel and a group of rats led by General Cortez enter the pyramid and a battle ensues. Shade discovers his father and Ishmael sacrifices himself to save his trapped brother. Voxzaco realizes that there is no way to sacrifice one hundred hearts before the brief eclipse ends, except by using the explosive disc brought by Goth. He therefore attempts to drop it on the pyramid. As it falls, Shade uses sound waves to keep it in place just long enough for most northern bats to escape. Exhausted, Shade lets it drop afterward, destroying the pyramid and killing all inside.
Victorious, the northern group returns to Bridge City and meets with the owl king for a truce. With Orestes' help, Boreal agrees to let bats fly in daylight. Afterward, Frieda, the eldest of the Silverwings, dies peacefully. A new Tree Haven is then built with Shade's mother Ariel as the new elder. Shade gets to know his father and the family adopts Chinook who was orphaned by the bombing. In the last scene, Marina reveals to Shade that Chinook had offered to make her his mate. She says that she refused, intending to be Shade's mate instead.
Sunwing was first released in Canada in August 1999. It was followed with its release in the United Kingdom and the United States in January 2000 and February 2000 respectively. Below is the release details for the first edition hardback and paperback copies in these three publication regions.