Ring-necked Parakeet Psittacula Krameri Research Articles

Alien parakeets as a potential threat to the common noctule Nyctalus noctula

The ring-necked parakeet Psittacula krameri (Aves: Psittaciformes) is a widely distributed species of Asian and African origin, which occurs with over 40 alien populations in the rest of the world. Most established populations of this species are showing a clear trend of territorial expansion and numerical growth. Recent reviews highlighted that one of the main impacts by alien ring-necked parakeets is the competition with threatened bat species using trunk cavities as roosts. In Italy, the only known reproductive population of Nyctalus bats (Mammalia: Chiroptera) occurs in an urban area in the central part of the country, surrounded by increasing and expanding populations of ring-necked parakeets. In this work, we updated the population status of both ring-necked and Alexandrine parakeets and breeding noctule bats in the region. Then, we ran a species distribution model using Maxent software to analyze the environmental suitability of the region for the ring-necked parakeet and a connectivity model using Circuitscape software to predict the possibility of its expansion in the area occupied by breeding noctule bats. We recorded a high number of individual parakeets and breeding colonies, together with a remarkable noctule population decline, from about 400 to about 120 individuals, in the last 20 years, possibly due to urban green management practices. Although some ring-necked parakeets have already been observed in the study area, there is no evidence of reproduction in the surroundings of the noctule colony. However, our model showed a high environmental suitability for the ring-necked parakeet in the area occupied by breeding noctules. As well, the connectivity model showed the potential for a direct flow of individuals from the main urban centers to the area used by noctule bats. The arrival of alien parakeets to the area occupied by the bat breeding colony should be tightly monitored by surveying the suitable areas for this bird, as well as the identified ecological corridors. Early detection of new invasions, together with a sustainable urban green management practice, may prevent the extinction of the southernmost breeding colony of the common noctule.

Nest tree preference shown by Ring-necked Parakeet Psittacula krameri (Scopoli, 1769) in northern districts of Tamil Nadu, India

This paper pertains to the nesting aspects of Psittacula krameri with specific reference to nesting-related habitats, number of individuals encountered, inter-specific interactions, and abnormalities in 71 villages covering seven northern districts of Tamil Nadu. A total of 797 nests (500 active and 297 non-active nests) and 1,119 individuals were enumerated on 284 trees and 13 temples/buildings belonging to eight species, seven genera, and five families. The highest number of nests (320) and birds (469) occurred on Borassus flabellifer L., followed by Cocos nucifera L., Albizia lebbeck (L.) Benth., Madhuca longifolia J.F.Gmel., Phoenix sylvestris (L.) Roxb., and Ficus benghalensis L. This species prefers dead trees than living trees for nesting. The study reveals that 63.4% nests (n= 505) and 65.1% birds (n= 729) were found on dead trees of B. flabellifer, C. nucifera, and P. sylvestris. They generally prefer to build nests on trees situated near agricultural lands, followed by those near water bodies, human settlements, and temples/buildings. Pearson’s chi-square test indicates that the birds showed preference towards certain nesting sites/nesting species. Inter-specific interactions occurred between P. krameri and Blue Rock Pigeon, Spotted Owlet, Indian Roller, and Black-rumped Flameback for sharing of cavities/holes for construction of nests. Abnormalities in bird’s beak, cere, colour of feathers, and a suspected psittacine beak & feather disease (PBFD) were observed.

Population counts and potential impact of two successful invaders in a town of Northern Italy: the case of ring-necked parakeet and Alexandrine parakeet in Reggio Emilia

In our paper, we reported the presence of two alien species in the city of Reggio Emilia, the ring-necked parakeet Psittacula krameri and the Alexandrine parakeet Psittacula eupatria. The ring-necked parakeet is widespread throughout Europe with many colonies known also for Italy, whereas the Alexandrine parakeet has been only recorded in the last 10-15 years and, apart from few individuals in Rome, the breeding population in Reggio Emilia is the largest one in Italy. We carried winter counts following standard methods through counts at roosts. About 78-80 ring-necked and at least 16 Alexandrine parakeets were counted, including also some hybrids between the two species, which were morphologically identified by the pale colour of the shoulders. Although no claims of crop damage are yet reported, parakeets of both species may feed on ripe and unripe persimmons in private gardens, reducing the total fruit production by up to 75-80%. Furthermore, four Savi’s pipistrelle Hypsugo savii have been killed by ring-necked parakeets in early spring 2019. Therefore, the current trend of these species in the town could lead to further expansion into suburban farmland areas, increasing potential conflicts with human activities.

Loud callings limit human tolerance towards invasive parakeets in urban areas

Biological invasions represent today one of the main cause of the global biodiversity crisis, particularly in urban and suburban areas. Research on this topic have traditionally focused on ecological impacts, with poor regards to the social components. The ring-necked parakeet Psittacula krameri is one of the most successful invaders and it is widely appreciated by the general public, being introduced through the pet trade. In this work we assessed whether long-term introduction, total population size and number of loud flight-calls affected social perception of this species in three populations from Italian cities. We used a visual survey (N = 414 questionnaires), which has been proven to be successful for testing attitudes on ring-necked parakeets. Tolerance towards this invasive species declined sharply with increasing number of loud calls by this species, thus providing support to the hypothesis of involvement of the ring-necked parakeet in noise pollution. Conversely, total population size and years since the first local introduction were not found out to be important variable determining social attitudes. Awareness on invasive species impacts is mostly obtained only when invasive populations are already affecting native biodiversity and human wellness, thus when management becomes challenging. Thus, at early invasion stages, intervention towards invasive species, particularly if charismatic, are often hampered by social public and animal right movements, especially in urban ecosystems. Educational campaigns on ecological and social impact by invasive alien species in urban ecosystems are therefore strongly recommended to implement effective management actions.

'Some like it alien': predation on invasive ring–necked parakeets by the long–eared owl in an urban area

Predation pressure by native species may limit the spread of alien invasive species, thus playing a pivotal role in the impact and implementation of management strategies. The ring–necked parakeet Psittacula krameri is one of the most widespread alien bird species in Europe, with nearly 70 established populations. Predators of this species include diurnal raptors, synanthropic corvids, and rodents. Here we report for the first time that long–eared owls Asio otus might have preyed upon parakeets in their night roosts. Analysis of 167 owl pellets showed that ring–necked parakeets made up over 10 % of the total volume of the diet of these owls in winter (32.93 % of absolute frequency), representing the most important prey species after murid rodents and passerine birds. Further studies are needed to investigate whether parakeet consumption by long–eared owls is only a local occurrence or whether it is widespread in European cities. If so, predation by long–eared owl may eventually lead to a form of parakeet control and may limit the impact of this introduced parakeet on native biodiversity.

‘Some like it alien’: predation on invasive ring–necked parakeets by the long–eared owl in an urban area

Predation pressure by native species may limit the spread of alien invasive species, thus playing a pivotal role in the impact and implementation of management strategies. The ring–necked parakeet Psittacula krameri is one of the most widespread alien bird species in Europe, with nearly 70 established populations. Predators of this species include diurnal raptors, synanthropic corvids, and rodents. Here we report for the first time that long–eared owls Asio otus might have preyed upon parakeets in their night roosts. Analysis of 167 owl pellets showed that ring–necked parakeets made up over 10 % of the total volume of the diet of these owls in winter (32.93 % of absolute frequency), representing the most important prey species after murid rodents and passerine birds. Further studies are needed to investigate whether parakeet consumption by long–eared owls is only a local occurrence or whether it is widespread in European cities. If so, predation by long–eared owl may eventually lead to a form of parakeet control and may limit the impact of this introduced parakeet on native biodiversity.

Estimating age-dependent survival when juveniles resemble females: Invasive ring-necked parakeets as an example.

Many species only show sexual dimorphism at the age of maturity, such that juveniles typically resemble females. Under these circumstances, estimating accurate age‐specific demographic parameters is challenging. Here, we propose a multievent model parameterization able to estimate age‐dependent survival using capture–recapture data with uncertainty in age and sex assignment of individuals. We illustrate this modeling approach with capture–recapture data from the ring‐necked parakeet Psittacula krameri. We analyzed capture, recapture, and resighting data (439 recaptures/resightings) of 156 ring‐necked parakeets tagged with neck collars in Barcelona city from 2003 to 2016 to estimate the juvenile and adult survival rate. Our models successfully estimated the survival probabilities of the different age classes considered. Survival probability was similar between adults (0.83, 95% CI = 0.77–0.87) and juveniles during their second (0.79, 95% CI = 0.58–0.87) and third winter (0.83, 95% CI = 0.65–0.88). The youngest juveniles (1st winter) showed a slightly lower survival (0.57, 95% CI = 0.37–0.79). Among adults, females showed a slightly higher survival than males (0.87, 95% CI = 0.78–0.93; and 0.80, 95% CI = 0.73–0.86, respectively). These high survival figures predict high population persistence in this species and urge management policies. The analysis also stresses the usefulness of multievent models to estimate juvenile survival when age cannot be fully ascertained.

A morphometric sexing approach for the Ring-necked Parakeet Psittacula krameri in Italy

ABSTRACTOnly one fact is certain when sexing the Ring-necked Parakeet visually: adult males have a rose-coloured ring and a black bib that is fully developed by their third year. Sexually immature males (those <3 years old) and females are considered impossible to separate without using biometric measures, some additional to those in previous literature. While the biometrics of males and females overlap broadly in value, males tend to be slightly larger than females in all measurements. We tested the possibility of sexing individuals of this species using a series of biometric measurements. A total of 97 parakeets were captured and measured in 2016–17. Measurements of wing length, tail length, bill length, height and thickness, tarsus length, mass, third-primary length and number of yellow underwing coverts were recorded for these individuals. In addition, photographs of the head and wing were taken. Feather samples were taken from all individuals for DNA extraction and 45 of these birds (26 females and 19 males) have been sexed. The measurements from these known-sex individuals were pooled with the measurements for adult males and a logistic regression of the known sexes was performed to verify whether the mean value of the biometric variables was statistically different between females and males. We found that it is possible to separate the sexes using morphological measures of wing, tail, bill length and thickness, tarsus and the number of yellow underwing coverts.

The Legal International Wildlife Trade Favours Invasive Species Establishment: The Monk and Ring-Necked Parakeets in Spain

The international wildlife trade is a lucrative business. Although a huge variety of animal groups are trafficked, the Psittaciformes (parrots) are amongst the most traded avian groups. Deliberate or accidental releases of imported parrots have led to the establishment of feral populations in many countries. Far from their native habitats, parrots may cause economic and ecological damage, and may even favour the transmission of zoonotic diseases. Despite this, the links between numbers of imported individuals and the establishment of non-native populations is not well known. In this study, we analysed data on imports of two well-known invasive parrots, the Monk Parakeet Myiopsitamonachus and the Ring-necked Parakeet Psittacula krameri, in Spain. We contrasted this information with the growth of known naturalised populations of these species from 1975 to 2015 and compared the success of these two species with other Psittaciformes imported in similar numbers into the country. We show that more than 190,000 Monk Parakeets were imported from Uruguay and Argentina, and almost 63,000 Ring-necked Parakeets were legally brought into the country from Pakistan and Senegal. For both species, wild populations grew exponentially following peak importation periods in 2015 (18,980–21,455 Monk Parakeets and 3,005–3,115 Ring-necked Parakeets). Even though imports of the two species were banned in Spain in 2005, wild populations are now self-sustaining. We argue that these parrot populations started from accidental and deliberate bird escapes, especially from birds originally captured in the wild. Although lack of more precise data makes it difficult for us to propose clear statistical associations between imports and established bird populations, we nonetheless suggest that the international trade is with some certainty the main cause for the origin of naturalised populations of invasive species in Spain. Our conclusions are useful to help manage similar animal groups that are numerous in the wildlife trade, especially for wild-caught social species.—Lucrecia Souviron-Priego, Antonio Roman Munoz, Jesus Olivero, J. Mario Vargas & John E. Fa. (2018). The legal international wildlife trade favours invasive species establishment: the Monk and Ring-neked Parakeets in Spain. Ardeola, 65: 233–246.

Vertical segregation by breeding ring-necked parakeets Psittacula krameri in northern Italy

Cavities represent a limiting resource for breeding birds, thus triggering potential competition, mostly in urban ecosystems. The ring-necked parakeet Psittacula krameri is one of the main alien invasive bird species of the world. Introduced populations are reported for over 35 countries, Italy included. This parakeet mainly depends on trunk cavities for reproduction but, occasionally, it may nest within building holes. A growing population of this species is present in the urban area of Pavia (northern Italy). Differently, from what has been observed in other colonies of the global introduced range, most of this urban population nests within the putlog holes of the Visconti castle and surrounding towers, together with four native species. In this work, we counted the breeding pairs of ring-necked parakeets nesting within putlog holes of castle and tower walls and estimated the breeding population size. Observations were carried out once a week, 30 min before sunset, for an hour, from the start of April to the end of August 2016 and 2017. We assessed whether a vertical segregation occurred between parakeets and native species (i.e. the rock pigeon, the jackdaw, the Italian sparrow and the common swift) through a dissimilarity index. Inter-specific interactions have never been observed, despite two pigeon ticks being detected on rescued parakeets. A strong vertical segregation was observed between ring-necked parakeets and pigeons, and between ring-necked parakeets and common swifts. Ring-necked parakeets and jackdaws were mostly observed in the highest putlog holes. No breeding parakeet pair was observed within plain trunk cavities in the surroundings of the castle walls, which were instead occupied by jackdaws and tawny owls. Most parakeet nests were located on the eastern wall, where they receive the first light at dawn.

“Kill Two Birds with One Stone”: Urban Tree Species Classification Using Bi-Temporal Pléiades Images to Study Nesting Preferences of an Invasive Bird

This study presents the results of object-based classifications assessing the potential of bi-temporal Pléiades images for mapping broadleaf and coniferous tree species potentially used by the ring-necked parakeet Psittacula krameri for nesting in the urban area of Marseille, France. The first classification was performed based solely on a summer Pléiades image (acquired on 28 July 2015) and the second classification based on bi-temporal Pléiades images (a spring image acquired on 24 March 2016 and the summer image). An ensemble of spectral and textural features was extracted from both images and two machine-learning classifiers were used, Random Forest (RF) and Support Vector Machine (SVM). Regardless of the classifiers, model results suggest that classification based on bi-temporal Pléiades images produces more satisfying results, with an overall accuracy 11.5–13.9% higher than classification using the single-date image. Textural and spectral features extracted from the blue and the NIR bands were consistently ranked among the most important features. Regardless of the classification scheme, RF slightly outperforms SVM. RF classification using bi-temporal Pléiades images allows identifying 98.5% of the tree species used by the ring-necked parakeet for nesting, highlighting the promising value of remote sensing techniques to assess the ecological requirements of fauna in urban areas.

Interference competition between an invasive parakeet and native bird species at feeding sites.

Interference competition has proved to be a factor of successful establishment of invasive species. This type of competition may have a stronger impact when native species have temporal niche overlap with the invasive species. The ring-necked parakeet Psittacula krameri has been successfully introduced in many countries and its interspecific agonistic behavior has already been reported. The purpose of this study is to analyze the territorial and preemptive interference competition between the ring-necked parakeet and native bird species in a recently colonized area. We used an empirical approach by recording video sequences in gardens equipped with bird feeders in winter. Our results showed that the ring-necked parakeet was the most frequent species at the feeders. Several native species showed temporal niche overlap with the ring-necked parakeet, the highest overlap being with the starling Sturnus vulgaris. The starling was also the species most impacted by interference competition with the parakeet. Our study suggests that, by being most frequently present at the feeders, by demonstrating the most agonistic behavior and by hindering access to food of the other species, the ring-necked parakeet is a superior competitor and may compete with native bird species.Electronic supplementary materialThe online version of this article (doi:10.1007/s10164-016-0474-8) contains supplementary material, which is available to authorized users.

Evaluating the population-level impact of an invasive species, Ring-necked Parakeet Psittacula krameri, on native avifauna

Evaluating the population-level impact of an invasive species, Ring-necked Parakeet Psittacula krameri, on native avifauna