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Efficacy of hand-broadcast application of baits containing 0.005% diphacinone in reducing rat populations in Hawaiian forests

November 1, 2013

Introduced black rats (Rattus rattus), Polynesian rats (R. exulans/i>), and Norway rats (R. norvegicus) impact insular bird, plant, and invertebrate populations worldwide. We investigated the efficacy of hand-broadcast application of Ramik® Green containing 0.005% diphacinone for rodent control in paired 4-ha treatment and non-treatment plots in both wet and mesic forest in Hawaiʽi. Radio telemetry of black rats, the predominant species, indicated 100% mortality in both treatment plots within about one week of bait application. Live trapping and non-toxic census bait block monitoring two to four weeks after each of 12 repeat bait applications in the wet forest, and three repeat bait applications in the mesic forest, indicated rat abundance was reduced on average by 84–88%. However, reinvasion could have occurred within this time. Rat populations in the treatment plots usually recovered to pre-poison levels within two to five months. House mice (Mus musculus), Indian mongooses (Herpestes auropunctatus), and feral cats (Felis catus) also ate bait or other animals that had eaten bait. This study demonstrates the efficacy of ground-based broadcast toxicant baits for the control of rats in Hawaiian montane wet forests.

Citation Information

Publication Year 2013
Title Efficacy of hand-broadcast application of baits containing 0.005% diphacinone in reducing rat populations in Hawaiian forests
DOI
Authors David Foote, Gerald D. Lindsey, Charlotte F. Perry, Eric Spurr
Publication Type Report
Publication Subtype Other Government Series
Series Title
Series Number TR HCSU-043
Index ID 70111901
Record Source USGS Publications Warehouse
USGS Organization Pacific Island Ecosystems Research Center