Countless individuals explored and collected Hawaiʻi’s unique flora and fauna. Here is described just a few in the fields of ornithology, entomology, and botany.
Scott Wilson explored the major islands in the late 1800s and along with A. Evans published Aves Hawaiienses: the birds of the Sandwich Islands. This was followed by Henry Palmer who collected extensively.
A description of ornithology exploration in Hawaiʻi is here: https://sora.unm.edu/sites/default/files/SAB_015_1994%20P91-102_A%20Chronology%20of%20Ornithological%20Exploration%20in%20the%20Hawaiian%20Islands…_Storrs%20L.%20Olson%2C%20Helen%20F.%20James.pdf.
The reverend Thomas Blackburn was a naturalist who was the first to study and make substantial collections in Hawaiʻi. The British entomologist R.C.L. Perkins was the first trained entomologist and collected extensively in the late 1800s into the early 1900s. His work was included in the multi-volume Fauna Hawaiiensis. A relatively recent book Barefoot on Lava on this journals and correspondence by has been written. Subsequently, many entomologists have contributed to documenting and cataloging Hawaiian arthropods.
There is a long list of individuals who collected in Hawaiʻi historically, as listed in Table 8 of the Manual of Flowering Plants of Hawaiʻi (Wagner et al. 1999). Several of the more prominent in earlier times are William Hillebrand (author of Flora of the Hawaiian Islands), Joseph Rock, Otto Degener (author of Flora Hawaiiensis), Harold St. John, and Raymond Fosberg.