The Effect of Familiarity on the Temporal Dynamics of Spatial and Affiliative Associations in Monk Parakeets

Simple SummaryThe monk parakeet (Myiopsitta monachus) is an invasive species, unique in the parrot family for its ability to build large nest structures. This species became globally distributed, promoted in part due to the pet trade market, and now is considered a pest because of the economic losses they produce. During the reproductive seasons of 2017 and 2018, we registered interactions between invasive monk parakeets and resident bird species in Santiago, Chile. We observed positive and negative interactions, and herein, we describe parakeets’ nest occupancy by nine bird species, two invasive and seven native. For this reason, the monk parakeet should be considered an ecosystem engineer, a species that is creating available breeding space of potential use for other species. Our results contribute to an assessment of implications of this ecological invasion of local urban wildlife, and raise concern on other impacts, such as disease transmission, as a consequence of these interactions.The monk parakeet (Myiopsitta monachus) is considered to be one of the most invasive bird species because its unique ability among parrots to build their own communal nests. Currently, they are considered an invasive species in 19 countries and a pest—even in their native distribution—because of economic losses derived from their impacts. During the reproductive seasons of 2017 and 2018, we registered interactions between invasive monk parakeets and resident bird species in Santiago, Chile. We observed agonistic and affiliative interactions, and further, we described monk parakeets’ nest occupancy by nine bird species, two invasive and seven native. For this reason, we consider that the monk parakeet is an allogenic ecosystem engineer with the potential to shape distribution and richness of sympatric species in urban environments. Our results contribute to an assessment of the implications of the monk parakeet’s ecological invasion to other synanthropic species, and raise concern of other potential impacts, such as pathogen transmission derived from these interactions.

Monk parakeets, Myiopsitta monachus Boddaert, are native to South America but have established populations in North America, Europe, Africa and Asia. They are claimed to act as agricultural pests in their native range, and their communal stick nests may damage human infrastructure. Although several monk parakeet populations are present in the Mediterranean Basin and temperate Europe, little empirical data are available on their population size and growth, distribution and potential impact. We investigated the temporal and spatial dynamics of monk parakeets in Israel to assess their invasion success and potential impact on agriculture. Monk parakeet populations are growing exponentially at a higher rate than that reported elsewhere. The current Israeli population of monk parakeets comprises approximately 1500 individuals. The distribution of the species has increased and shifted from predominantly urban areas to agricultural landscapes. In Israel, monk parakeet populations are growing fast and have dispersed rapidly from cities to agricultural areas. At present, reports of agricultural damage are scarce. A complete assessment of possible management strategies is urgently needed before the population becomes too large and widespread to allow for cost-effective mitigation campaigns to be implemented. © 2016 Society of Chemical Industry.

The effects of second-neighbor spin coupling interactions and a magnetic field are investigated on the free energies of a finite-size 1-D Ising model. For both ferromagnetic of nearest neighbor (NN) and next-nearest neighbor (NNN) spin coupling interactions, the finite-size free energy first increases and then approaches a constant value for any size of the spin chain. In contrast, when NNN and NN spin coupling interactions are antiferromagnetic and ferromagnetic, respectively, the finite-size free energy gradually decreases by increasing the competition factor and eventually vanishes for large values of it. When a magnetic field is applied, the finite-size free energy decreases with respect to the case of zero magnetic fields for both ferromagnetic and antiferromagnetic spin coupling interactions. Deviation of free energy per size for finite-size systems relative to the infinite system increases when the spin coupling interactions as well as the f parameter (the ratio of the magnetic field to NN spin coupling interaction) increase.

Monk parakeets (Myiopsitta monachus) are the most abundant and widely distributed of the naturalized parrots in the United States. We summarize monk parakeet population data from 1970 to 2010 for northern Illinois, one of the best-known populations. Throughout the 1970s, parakeets were seen in small numbers at scattered locations, but none of the nesting sites persisted and the birds either died or moved elsewhere. The species became established in the Hyde Park neighborhood of Chicago in 1979 and this population grew exponentially and expanded over the next 25 years, doubling in size every 2 to 3 years. In the mid to late 1990s parakeets became established in many other localities in the Chicago region. The population in Hyde Park began to rapidly decline in 2005, a trend also exhibited in national counts. The reasons for this decline are unknown but we suggest that the decline is more apparent than real and that the decline in Hyde Park is the result of shifts in population structure from a few dense aggregations to progressively more spatially separated smaller groups. As evidence for this, the population of parakeets in the greater Chicago region does not appear to have declined but is still growing in size and distribution. Monk parakeets are a novel addition to many urban ecosystems, with a neutral impact to most other bird species but an increasingly complex interaction with human residents in urban areas.

Parasite-mediated competition has been reported to be one of the most harmful, although overlooked, impacts that alien species have on native ecosystems. Monk parakeets Myiopsitta monachus are successful invaders in Europe, where they have been introduced from South America. Colonial nests of these parrots may also host other species, e.g. the rock pigeon Columba livia forma domestica. In this work, we analysed the ectoparasite composition of monk parakeets in Barcelona (Spain) and we evaluated their potential role as parasite-mediated competitors, by comparing their parasitic load with that of coexisting rock pigeons. Only two arthropod species were observed on monk parakeets, whereas four species were detected on pigeons. Parakeets were rarely infested by pigeon parasites (prevalence = 0.66%), whereas parakeet mites were recorded more often on pigeons (prevalence = 10.00%). The number of total parasites per bird increased with increasing densities of monk parakeets, both for pigeons and for parakeets. Therefore, overcrowding of birds due to the increasing population of monk parakeets in Barcelona may affect the health status of native pigeons, suggesting a potential role for parasite mediated competition by introduced parakeets. Furthermore, spill-over of alien mites (Ornithonyssus bursa) by monk parakeets to rock pigeons should be monitoring as it may affect human health.

Author(s): Pruett-Jones, Stephen; Tarvin, Keith A. | Abstract: Records from Christmas Bird Counts were summarized to assess population growth of the Monk parakeet (Myiopsitta monachus) in the United States from 1975 to 1996. Population growth over this period fits an exponential model of population growth with a current annual rate of increase of 12.9% and a doubling time of 5.4 years. Since 1990, however, population growth on a national scale has slowed considerably, suggesting that the species may be approaching a carrying capacity. In contrast to the results across the entire United States, the population of monk parakeets in northeastern Illinois has dramatically increased in numbers within the last decade. In this region, the Hyde Park, Chicago population appears to be acting as a source from which other areas are colonized. The monk parakeet is known to have caused damage to fruit crops in Florida, and they can be a nuisance species to local utility companies when they build their nests on power transformers. Nevertheless, such damage is highly localized and, on a national scale, there is no evidence to date that monk parakeets should be considered a pest species and subject to widespread control. The initiation of detailed studies of a banded population of this species is recommended

Human-wildlife interactions continue to increase due to anthropogenic disturbances, with some interactions resulting in conflict. Leveraging a taxa’s bias for a particular sensory cue is a promising management avenue for reducing the potential and realized negative consequences of human-wildlife conflict. For instance, many avian species heavily depend on acoustic communication, and acoustic cues can provide opportunities to reduce conflict with various avian species. The monk parakeet (Myiopsitta monachus) is a gregarious parrot native to South America that has established populations worldwide and is considered an urban and agricultural pest in parts of its native and introduced ranges. We conducted playback experiments with a captive population of monk parakeets to evaluate auditory cues that may be useful for designing management protocols. Our experiment evaluated the efficacy of two stimuli: predator vocalizations as potential repulsion and conspecific vocalizations as potential attraction stimuli for parakeets. We measured two responses: (1) categorical group-level behavioral responses and (2) time to cease vigilance and return to behavior prior to playback. In the repulsion playbacks, monk parakeets were repelled by predator vocalizations in 80% of trials and took longer to cease vigilance and return to baseline behavior compared to attraction playbacks. In the attraction playbacks, monk parakeets exhibited vigilant behavior and weak or no attraction to the stimulus, with attraction only being observed in 10% of trials. Our results demonstrate that predator playbacks may be particularly useful for completing management objectives, such as temporary removal from a location.

The standard approach for characterizing boldness rarely considers the influence of social environment on the expression of boldness in group-living animals. We studied a wild-caught, captive population of monk parakeets (Myiopsitta monachus) to investigate the impact of conspecific presence on boldness — a personality trait in monk parakeets — in a controlled environment. We quantified seven boldness metrics across three types of behavioural assay: novel object, emergence, and predator exposure tests in the presence of a companion pair of flock mates. Because of the high degree of sociality in this species, we hypothesized that the presence of companion birds would facilitate the focal individuals’ behavioural responses (i.e., increase the average boldness level). We found that behavioural response in a risky foraging context was inversely correlated between solitary and social condition in males, but not in females. Our results have implications for characterizing sex-specific differences of risk-taking behaviour in social animals.

Sex composition modulates the effects of familiarity in new environment

Simple SummaryMonitoring programs are crucial to understanding and managing invasive species populations. However, they are infrequent and not usually conducted in the long term. In this work, we used population censuses and observational data from citizen science platforms to monitor the growth and expansion of populations of two invasive species established in Seville (Spain): the rose-ringed parakeet and the monk parakeet. During our study period (2013–2021), rose-ringed and monk parakeet populations increased fivefold and twentyfold, respectively. These rapid population growths coincided with the increasing number of observations of both species recorded by volunteer birdwatchers, as well as the increasing expansion of monk parakeets throughout the study area. Citizen science can be useful for roughly knowing the population status of invasive species, but it cannot replace specific monitoring programs to understand their spatiotemporal dynamics.Population changes of invasive species can go unnoticed long before population explosions, so long-term monitoring programs are needed to assess changes in population size. Although invasive populations of rose-ringed (Psittacula krameri) and monk parakeets (Myiopsitta monachus) are present worldwide, their current status and dynamics are mostly poorly known. Here, we provide a long-term population monitoring of both parakeet species established in a Mediterranean urban area. Between 2013 and 2021, we conducted systematic population censuses in the city of Seville and collected their occurrence and spatial distribution data from citizen science platforms. Our censuses showed a rapid population growth of both species: rose-ringed parakeets increased from 1200 to 6300 individuals, while monk parakeets increased from 70 to 1487 individuals. These population trends were weakly reflected by the number of parakeet observations and the number of cells with parakeet observations but not by the number of individuals recorded in citizen science platforms. Moreover, for the monk parakeet, the number of cells with observations was related to the spatial spread of its nests across the study area. Although resource-intensive, long-term monitoring programs are essential to assess population changes and develop effective management actions for invasive species. Thus, contrasting this information with data taken through citizen science platforms can validate the utility of the latter for assessing population status of invasive species.

The Monk Parakeet (Myiopsitta monachus) commonly uses utility poles as a substrate for building large, bulky nests. These nests often cause fires and electric power outages, creating public safety risks and increasing liability and maintenance costs for electric companies. Previous research has focused on lethal methods and chemical contraception to prevent nesting on utility poles and electrical substations. However, implementation of lethal methods has led to public protests and lawsuits, while chemical contraception may affect other than the targeted species, and must be continually reapplied for effectiveness. One non-lethal alternative, nest removal, is costly and may not be a sustainable measure if Monk Parakeet populations continue to grow. In order to identify cost-effective non-lethal solutions to problems caused by Monk Parakeet nesting, we studied their behavior as they built nests on utility poles. Monk Parakeets initiate nests by attaching sticks at the intersection of the pole and electric lines. We found that parakeets use the electric lines exclusively to gain access to the intersection of lines and pole during nest initiation, and continue to use the lines intensively throughout construction. Monk Parakeets also have more difficulty attaching sticks during the early stages of nest construction than when the nest is nearing completion. These findings suggest that intervention during the earlier stages of nest building, by excluding Monk Parakeets from electric lines adjacent to poles, may be an effective, non-lethal method of reducing or eliminating parakeets nesting on, and damaging, utility poles.

Managing invasive species has become a major environmental challenge due to their global ecological and socioeconomic impacts. Prioritising effective strategies is essential, especially given the often limited funding. Data from real control programmes are crucial for developing long-term management plans. Between May 2021 and April 2023, the City of Madrid implemented a control plan to reduce its monk parakeet (Myiopsitta monachus) population. This study assessed: (1) the plan’s efficacy, (2) the impact of removing different age classes on population viability, (3) the capture efficacy and cost-efficiency of various capture methods, (4) the optimal combination of capture methods and (5) the effectiveness of different baits in attracting parakeets. The plan eliminated approximately 87% of the juvenile and adult population present at the plan’s onset, reducing total population projections for 2023 and 2031 by 50%. Projections indicated that maintaining the second-year removal intensity for three additional years could have nearly eradicated the species. Removing juveniles and adults proved more than twice as effective at curbing population growth as targeting eggs and nestlings, leading to prioritising juvenile and adult removal year-round. Of the five methods used – shooting, folding net, hand-held net launcher, egg culling and nestling culling – shooting was the most effective in reducing population growth both in and outside spring. Optimisation models suggested prioritising shooting and the combination of folding net and net launcher in spring and exclusively the latter outside spring. We recommend using the shooting method year-round, complemented by the combined use of the folding net and net launcher outside of the spring season. Bread and a mixture of bread, apple and parrot feed were the most effective and cost-efficient baits attracting parakeets, with bread recommended for simplicity. This study enhances understanding of parrot management strategies, offering insights for more effective and cost-efficient control of invasive monk parakeet populations.

Feral monk parakeet (Myiopsitta monachus) populations have become established in the United States and other countries around the world, and can cause damage to electrical facilities. Because the monk parakeet is a highly visible species and there is often public opposition to lethal control measures, non-lethal methods, such as contraception, are being developed to help control the spread of feral populations. Two gavage studies and one ad libitum nesting study were conducted to assess the efficacy of DiazaCon™ as a potential contraceptive for the monk parakeet. The first gavage study compared daily dose levels of 0, 50, 75, and 100 mg DiazaCon™ (kg bodyweight)–1 administered for 10 consecutive days. Cholesterol concentrations decreased significantly concomitant with a significant increase in desmosterol concentrations in the treated groups, but did not vary between sexes. Cholesterol and desmosterol concentrations did not differ significantly among DiazaCon™ groups, and cholesterol remained significantly suppressed 12 weeks after treatment. On the basis of these results, the second gavage study compared 5 or 10 consecutive days of DiazaCon™ administration at 50 mg kg–1 bird–1 day–1. Cholesterol concentrations decreased significantly concomitant with a significant increase in desmosterol concentrations in the treated groups, but did not vary between sexes. Cholesterol and desmosterol concentrations did not differ significantly between DiazaCon™ groups, and cholesterol remained significantly suppressed 11 weeks after treatment. Parakeets in the nesting study were fed hulled sunflower seeds treated with a target dose of 50 mg DiazaCon™ kg–1 bird–1 day–1. Birds consumed enough to receive an average dose of 34 mg kg–1 pair–1 day–1, or 17 mg kg–1 bird–1 day–1. Birds in the treated group laid an average of 1.6 ± 0.7 eggs per clutch compared with 3.9 ± 1.1 eggs per clutch in the untreated control group. None of the eggs laid by treated birds hatched compared with 1.1 ± 0.6 eggs per clutch hatching in the control group. Reproductive inhibition was effective for the length of the breeding season, at which time the study was stopped and no more data were collected. DiazaCon™ is a promising avian oral contraceptive that should be further investigated in a field setting with monk parakeets.

Pairwise thermal entanglement in the three-qubit XXX Heisenberg model with next nearest neighbor interaction and a nonuniform magnetic field has been studied. It's found that the next nearest neighbor interaction has a great effect on the entanglement between the next nearest neighbor sites, but has slight effect on the nearest neighbor entanglement (NNE). Applying a magnetic field at the middle site enhances the next nearest neighbor entanglement (NNNE) sharply when there is a small field at the side sites and the next nearest neighbor coupling constant is positive. A staggered magnetic field helps to maintain nearest neighbor entanglement obviously.

The lattice Green’s functions for a linear chain with next nearest neighbor (NNN) interactions, Gl(t,A) = (1/r)ℱr0 coslxdx/[tie−(cos x+Acos2x)] are studied for various values of A, the ratio of NNN to nearest neighbor (NN) interactions. It is shown that Gl(t,−A) = (−1)l+1[Gl(−t,A)]*, thereby allowing attention to be restricted to the positive range of A which further divides into the two cases, (a) 0⩽A⩽1/4, with band edge singularities, and, (b) 1/4<A<∞, with an additional in-band singularity. Exact results are then obtained for the imaginary parts of Gl and for the real parts of G0 and G1. Finally a recurrence relation enables the real parts of Gl for arbitrary l to be found from those for l = 0 and 1.