Accurate estimates of vital rates like survival and reproduction are the foundation for endangered species management and recovery planning. Where new data are collected, analyses and conservation actions can be updated according to the best available knowledge. In this short communication, we update vital rate estimates for the Hawaiian Common Gallinule (Gallinula galeata sandvicensis), an endangered subspecies endemic to the Hawaiian Islands of Kaua‘i and O‘ahu, using newly available field data. These new data more than double the sample size used for initial vital rate estimates from a 2018 publication, and include the first ever published estimates of brood survival for this subspecies. The latter is considered a major knowledge gap for population modeling and conservation planning for this taxon. We estimated the mean probability of brood survival for the first month post-hatch at 0.90 for both islands combined, 0.82 on Kaua‘i and 0.98 on O‘ahu. For both populations combined, we observed a smaller mean clutch size (4.76 vs. 5.10), similar mean nest success (0.64 vs. 0.66), similar brood size (2.55 vs. 2.51), lower brood size per successful nest (3.77 vs. 3.86), and similar hatch rate (0.53 vs. 0.52) to the original study published in 2018. Received 13 May 2023. Accepted 28 December 2023.

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