Supplement 1. Data on species incidences, island group membership, and coordinates of island perimeters.

File List bismarcks-islands.csv (MD5: 85146e9d4760445ca261e985f44d75c7) bismarcks-species-matrix.csv (MD5: 68d0b38c7c352c5575cbbc12ae80088f) nhbirds-islands.csv (MD5: adfeffb8b2367698c71a79df58a7e282) nhbirds-species-matrix.csv (MD5: cbc955403bb8d17d81c123a3c7a59c6a) solomons-islands.csv (MD5: dc09dfb69d2674dd790c6947944921c8) solomons-species-matrix.csv (MD5: 5605bc6505efabdd98c4b77816723e6d) Description bismarcks-islands.csv - A data file for the Bismarck islands with island names and associations in columns B–G, coordinates of island perimeters in columns Y–BV, and coordinates of approximate island mid-points in column CA–CB. Column pairs give latitude and longitude in decimal degrees. bismarcks-species-matrix.csv - A data file for the Bismarck islands with species names in column A, species and genus codes in columns E–F, guild membership in column G–H, and guild codes in columns H–I. The species incidence matrix is in columns J–AX (rows 2–151). Island abbreviations in row 1 (columns J–AX), and the island group code for each island in row 153 (columns J–AX). The island group memberships for each species are found in columns AZ–BC (rows 2–151). nhbirds-islands.csv - A data file for Vanuatu with island names in column A, the coordinates of the approximate mid-points of each island in columns B–C, and the coordinates of the island perimeters in columns E–AN. Each pair of columns gives the latitude and longitude of a coordinate in decimal degrees. nhbirds-species-matrix.csv - A data file for Vanuatu with species, genus, and family names in columns A–C. Columns D–G contain the family code, genus code, multi-species genus code, and guild codes of each species. Columns H–AI gives the species incidence matrix. solomons-islands.csv - A data file for the Solomon Islands with island number in column A, island abbreviation in column B, island name in column C, the coordinates of the approximate mid-points of each island in columns AU–AV, and the coordinates of the island perimeters in columns D–AS. Each pair of columns gives the latitude and longitude of a coordinate in decimal degrees. solomons-species-matrix.csv - A data file for the Solomon Islands with species, genus, family names, and codes in columns A–J, and guild codes in columns K–M. Columns The species incidence matrix is in columns O–EZ (rows 2–142). Island abbreviations in row 1 (columns O–EZ), and the island group code for each island in row 144 (columns O–EZ). The island group memberships for each species are found in columns FB-FG (rows 2–142).