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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. Depredation of crops by this species causes extensive economic losses. Large congregations in evening roosts damage trees and lead to excessive noise and droppings in public areas. We evaluated the efficacy of a roost culling program conducted by an independent contractor from March 2020 – 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, 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 ratio of culled juveniles to adults was approximately 1.6:1.0. Age and sex structure of animals removed varied seasonally; 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. This study 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 can be used to inform implementation of roost culling for management of nonnative rose-ringed parakeet populations.

This datasheet on Rattus rattus covers Identity, Overview, Distribution, Dispersal, Hosts/Species Affected, Diagnosis, Biology & Ecology, Environmental Requirements, Natural Enemies, Impacts, Prevention/Control, Further Information.

The nematode Angiostrongylus cantonensis is a rat lungworm, a zoonotic pathogen which causes a global, emerging infectious disease known as rat lungworm disease (RLWD). RLWD has been reported in 30 countries, and Hawaii is the epicenter for RLWD in the United States. We conducted a study in wild Hawaiian rats (Rattus rattus) to determine the efficacy of a vaccine developed against a related species (A. costaricensis). Twenty-eight wild adult rats were captured from Waiakea Forest Reserve on the Island of Hawaii. Rats were mated and 41 F1 offspring were vaccinated with two doses of PP2A vaccine, a serine/threonine phosphatase 2A recombinant peptide (4 µg vaccine and 4 µg adjuvant/25 g body weight) at >3 mos. of age. Rats were gavaged with 50 L3 stage larvae at four weeks post-vaccination. Rats were euthanized and necropsies conducted at 51-53 days PI. Spleen weight, spleen length, and lung weight were recorded and number of worms in heart and lungs counted. Adult worms were found in all F1 rats. An average of 20.88 worms/rat reached adulthood with an infective dose of 50 L3 stage larvae. We found no significant differences between vaccinated rats (n=21) and unvaccinated rats (n=20) in spleen weight (p=0.963), spleen length (p=0.830), lung weight (p=0.830) or number of worms collected from the heart and lungs (p=0.882), suggesting the vaccine does not provide adequate protective immunity to guard against infection by A. cantonensis in wild Hawaiian rats.

Stars that evaporate from the Hyades cluster will remain within a few hundred parsecs of the cluster only if they are dynamically bound to a much more massive entity containing the cluster. A local mass enhancement of at least (5-10) x 10 exp 5 solar masses, with a radius of about 100 pc, can trap stars with an origin related to that of the Hyades cluster and explains the excess of stars with velocities near the Hyades velocity that constitutes the Hyades supercluster. Part of this mass enhancement can be in visible stars, but a substantial fraction is likely to be in the form of dark matter.