The 'adds nothing new' remark in the review seems odd, because I've found many aspects new to me in comparison with the original book. On taxa that also appear in Oceanic Birds of the World, Howell & Zufelt 2019, Seabirds on the whole is slightly more conservative, although much mention is made of the H & Z take on likely future splits. Furthermore, there are a fair number of very useful references cited, some of which had passed me by or have just become available. For example, Mascarene Petrel Pseudobulweria aterrima post-breeding dispersal from Réunion is shown to be widespread from the Arabian Sea to NW Australia; that's from only the 14 birds whose tags functioned for a year. A summary of this research is given in Saunier et al 2021: it's worth googling the LIFE+ Pétrels project - they also are establishing conservation measures for Barau's Petrel Pterodroma baruai that nests on very steep slopes at 2800 to 3000m altitude on Réunion.
MJB
Saunier, M, J Dubos, P Pinet, L Humeau, C Caumes, P Souharce, YS Mattoir, M Riethmuller, M Le Corre and A Jaeger. 2021. Phenology, at sea distribution and activity of a critically endangered seabird, the Mascarene petrel. LIFE+ Pétrels project (LIFE13BIO/FR/) Poster presentation.