Evaluation of Roost Culling as a Management Strategy for Reducing Invasive Rose‑Ringed Parakeet (Psittacula krameri) Populations

Authors

C. Janes Anderson, Texas A&M University–KingsvilleFollow
Leonard A. Brennan, Texas A&M University–Kingsville
William P. Bukoski, USDA-APHIS, Lihue, Hawaii
Steven C. Hess, National Wildlife Research Center, Hawai‘i Field Station
Clayton D. Hilton, Texas A&M University–Kingsville
Aaron B. Shiels, USDA, APHIS, Wildlife ServicesFollow
Shane Siers, USDA National Wildlife Research CenterFollow
Bryan M. Kluever, NWRC, GainesvilleFollow
Page E. Klug, NWRC, FargoFollow

ORCID IDs

C. Jane Anderson http://orcid.org/0000-0002-7472-4242

Steven C. Hess http://orcid.org/0000-0001-6403-9922

Shane R. Siers http://orcid.org/0000-0001-7961-5072

Bryan M. Kluever http://orcid.org/0000-0001-8417-4339

Page E. Klug http://orcid.org/0000-0002-0836-3901

Document Type

Article

Date of this Version

2023

Citation

Biological Invasions (2023) 25: 1,403–1,419

https://doi.org/10.1007/s10530-022-02984-3

Comments

U.S. government work

Abstract

Rose-ringed parakeets (Psittacula krameri) are one of the most widespread invasive avian species worldwide. This species was introduced to the island of Kaua‘i, Hawai‘i, USA, in the 1960s. The rapidly increasing population has caused substantial economic losses in the agricultural and tourism industries. We evaluated the efficacy of a roost culling program conducted by an independent contractor from March 2020 to March 2021. We estimated island-wide minimum abundance was 10,512 parakeets in January 2020 and 7,372 in April 2021. Over 30 nights of culling at four roost sites, approximately 6,030 parakeets were removed via air rifles with 4,415 (73%) confirmed via carcasses retrieval. An estimated average of 45 parakeets were removed per hour of shooter effort. The proportion of adult females removed in 2020 was 1.9 × greater when culled outside of the estimated nesting season. Of the four roosts where culling occurred, the parakeets fully abandoned three and partially abandoned one site. Of the three fully abandoned roosts, an estimated average of 29.6% of birds were culled prior to roost abandonment. The roost culling effort was conducted during the COVID-19 pandemic, when tourist numbers and foot traffic were greatly reduced. It is unknown how public perception of roost culling in public areas may impact future efforts. Findings suggest roost culling can be utilized for management of nonnative roseringed parakeet populations when roost size is small enough and staff size large enough to cull entire roosts in no greater than two consecutive nights (e.g., if two shooters are available for three hours per night, roost culling should only be attempted on a roost with ≤ 540 rose-ringed parakeets).