Genomic insights into the critically endangered King Island scrubtit.

Small, fragmented or isolated populations are at risk of population decline due to fitness costs associated with inbreeding and genetic drift. The King Island scrubtit Acanthornis magna greeniana is a critically endangered subspecies of the nominate Tasmanian scrubtit A. m. magna, with an estimated population of < 100 individuals persisting in three patches of swamp forest. The Tasmanian scrubtit is widespread in wet forests on mainland Tasmania. We sequenced the scrubtit genome using PacBio HiFi and undertook a population genomic study of the King Island and Tasmanian scrubtits using a double-digest restriction site-associated DNA (ddRAD) dataset of 5,239 SNP loci. The genome was 1.48 Gb long, comprising 1,518 contigs with an N50 of 7.715 Mb. King Island scrubtits formed one of four overall genetic clusters, but separated into three distinct subpopulations when analysed independently of the Tasmanian scrubtit. Pairwise FST values were greater among the King Island scrubtit subpopulations than among most Tasmanian scrubtit subpopulations. Genetic diversity was lower and inbreeding coefficients were higher in the King Island scrubtit than all except one of the Tasmanian scrubtit subpopulations. We observed crown baldness in 8/15 King Island scrubtits, but 0/55 Tasmanian scrubtits. Six loci were significantly associated with baldness, including one within the DOCK11 gene which is linked to early feather development. Contemporary gene flow between King Island scrubtit subpopulations is unlikely, with further field monitoring required to quantify the fitness consequences of its small population size, low genetic diversity and high inbreeding. Evidence-based conservation actions can then be implemented before the taxon goes extinct.

Exploration of how youth justice staff perceive the speech-language pathology role and service provision in an Australian youth justice setting.

PURPOSE: The aims of this project were to explore how youth justice staff perceive the speech-language pathology role and provision in an Australian youth justice setting, including the speech-language pathologist's role in supporting young people to participate in the activities of the youth justice service studied. METHOD: A narrative inquiry approach was employed to guide semi-structured interviews with youth justice staff. Perceptions and experiences were analysed via reflexive thematic analysis, with member checking and inter-rater coding utilised for rigour. RESULT: Seven semi-structured interviews were conducted. Interviewees worked in either the custodial setting (n = 3) or the community setting (n = 4) for the youth justice service studied, though most had worked in both settings. Six themes and six subthemes were identified from the interview data and related to factors that supported improved participation in the activities of the youth justice service studied. These factors were the speech-language pathology skillset and approach, and that there were systemic barriers within the service. All participants perceived speech-language pathology input as valuable for the young people in the service studied. There was also acknowledgement by the participants of how speech, language, and communication needs of the young people impacted their participation in the activities of the service studied. These findings were despite the perceived need for organisation-wide education on the speech-language pathologist role and offering. CONCLUSION: Increased understanding of how youth justice staff perceive the role and benefits of speech-language pathology in supporting young people in contact with the youth justice system will assist with service planning, inform education strategies, and may support policy change.

Giant coronary aneurysm in a toddler with Kawasaki disease: technical challenges in CT coronary angiography.

Kawasaki disease is the most common vasculitis causing acquired coronary artery aneurysm (CAA) and affects mostly children. Computed tomography coronary angiography (CTCA) has unique diagnostic and prognostic values in cases of giant CAA. Here, we report technical challenges encountered when performed CTCA for a case of Kawasaki disease complicated with giant CAA. In particular, there was significant flow alteration caused by the giant CAA(s) causing suboptimal enhancement when the standard protocol was applied. We share our experience in optimizing the scan and propose the use of either manual bolus tracking or test bolus technique in similar scenarios, as well as multidisciplinary approach to optimize patient preparation.

Tuberculosis revisted: classic imaging findings in childhood.

Tuberculosis (TB) remains one of the major public health threats worldwide, despite improved diagnostic and therapeutic methods. Tuberculosis is one of the main causes of infectious disease in the chest and is associated with substantial morbidity and mortality in paediatric populations, particularly in low- and middle-income countries. Due to the difficulty in obtaining microbiological confirmation of pulmonary TB in children, diagnosis often relies on a combination of clinical and radiological findings. The early diagnosis of central nervous system TB is challenging with presumptive diagnosis heavily reliant on imaging. Brain infection can present as a diffuse exudative basal leptomeningitis or as localised disease (tuberculoma, abscess, cerebritis). Spinal TB may present as radiculomyelitis, spinal tuberculoma or abscess or epidural phlegmon. Musculoskeletal manifestation accounts for 10% of extrapulmonary presentations but is easily overlooked with its insidious clinical course and non-specific imaging findings. Common musculoskeletal manifestations of TB include spondylitis, arthritis and osteomyelitis, while tenosynovitis and bursitis are less common. Abdominal TB presents with a triad of pain, fever and weight loss. Abdominal TB may occur in various forms, as tuberculous lymphadenopathy or peritoneal, gastrointestinal or visceral TB. Chest radiographs should be performed, as approximately 15% to 25% of children with abdominal TB have concomitant pulmonary infection. Urogenital TB is rare in children. This article will review the classic radiological findings in childhood TB in each of the major systems in order of clinical prevalence, namely chest, central nervous system, spine, musculoskeletal, abdomen and genitourinary system.

A synthesis of deimatic behaviour.

Deimatic behaviours, also referred to as startle behaviours, are used against predators and rivals. Although many are spectacular, their proximate and ultimate causes remain unclear. In this review we aim to synthesise what is known about deimatic behaviour and identify knowledge gaps. We propose a working hypothesis for deimatic behaviour, and discuss the available evidence for the evolution, ontogeny, causation, and survival value of deimatic behaviour using Tinbergen's Four Questions as a framework. Our overarching aim is to direct future research by suggesting ways to address the most pressing questions in this field.

The molecular architecture of cell cycle arrest.

The cellular decision governing the transition between proliferative and arrested states is crucial to the development and function of every tissue. While the molecular mechanisms that regulate the proliferative cell cycle are well established, we know comparatively little about what happens to cells as they diverge into cell cycle arrest. We performed hyperplexed imaging of 47 cell cycle effectors to obtain a map of the molecular architecture that governs cell cycle exit and progression into reversible ("quiescent") and irreversible ("senescent") arrest states. Using this map, we found multiple points of divergence from the proliferative cell cycle; identified stress-specific states of arrest; and resolved the molecular mechanisms governing these fate decisions, which we validated by single-cell, time-lapse imaging. Notably, we found that cells can exit into senescence from either G1 or G2; however, both subpopulations converge onto a single senescent state with a G1-like molecular signature. Cells can escape from this "irreversible" arrest state through the upregulation of G1 cyclins. This map provides a more comprehensive understanding of the overall organization of cell proliferation and arrest.

Association of HIV infection and antiretroviral therapy with the occurrence of an unfavorable TB treatment outcome in a rural district hospital in Eastern Cape, South Africa: A retrospective cohort study.

BACKGROUND: Our objective was to assess differences in TB treatment outcomes between individuals who were HIV negative, HIV positive on anti-retroviral treatment (ART) and HIV positive not on ART, at TB treatment initiation at a rural district hospital in Eastern Cape, South Africa. METHODS: This was a retrospective cohort study of individuals diagnosed with TB between January 2017 and April 2020 at a district hospital. Adults 15 years and over with reported HIV status and treatment outcome were included (N = 711). A categorical outcome with three levels was considered: unfavorable, down referral, and success. We report descriptive statistics for the association between HIV and ART status and treatment outcome using Chi-square and Fisher's exact tests. A multinomial baseline logit model was used to estimate odds ratios for treatment outcomes. RESULTS: Overall, 59% of included patients were HIV positive with 75% on ART. Eighty-eight patients 12% had an unfavorable outcome. Half of all patients were down referred with an additional 37% having a successful outcome. Individuals without HIV were more likely to be down referred (versus unfavorable) compared to individuals with untreated HIV (2.90 OR, 1.36, 6.17 95% CI). There was a greater likelihood for individuals without HIV having a successful TB treatment outcome compared to individuals with untreated HIV (4.98 OR, 2.07, 11.25 95% CI). CONCLUSION: The majority of individuals had positive TB treatment outcomes (down referred or success). However, people without HIV had nearly five times greater odds of having successful outcomes than those with untreated HIV.

The structure of the human cell cycle.

Understanding the organization of the cell cycle has been a longstanding goal in cell biology. We combined time-lapse microscopy, highly multiplexed single-cell imaging of 48 core cell cycle proteins, and manifold learning to render a visualization of the human cell cycle. This data-driven approach revealed the comprehensive "structure" of the cell cycle: a continuum of molecular states that cells occupy as they transition from one cell division to the next, or as they enter or exit cell cycle arrest. Paradoxically, progression deeper into cell cycle arrest was accompanied by increases in proliferative effectors such as CDKs and cyclins, which can drive cell cycle re-entry by overcoming p21 induction. The structure also revealed the molecular trajectories into senescence and the unique combination of molecular features that define this irreversibly arrested state. This approach will enable the comparison of alternative cell cycles during development, in response to environmental perturbation and in disease. A record of this paper's transparent peer review process is included in the supplemental information.

Prospective assessment of adjunctive ultrasound-guided diffuse optical tomography in women undergoing breast biopsy: Impact on BI-RADS assessments.

PURPOSE: To assess the impact of adjunctive ultrasound guided diffuse optical tomography (US-guided DOT) on BI-RADS assessment in women undergoing US-guided breast biopsy. METHOD: This prospective study enrolled women referred for US-guided breast biopsy between 3/5/2019 and 3/19/2020. Participants underwent US-guided DOT immediately before biopsy. The US-guided DOT acquisition generated average maximum total hemoglobin (HbT) spatial maps and quantitative HbT values. Four radiologists blinded to histopathology assessed conventional imaging (CI) to assign a CI BI-RADS assessment and then integrated DOT information in assigning a CI&DOT BI-RADS assessment. HbT was compared between benign and malignant lesions using an ANOVA test and Tukey's test. Benign biopsies were tabulated, deeming BI-RADS ≥ 4A as positive. Reader agreement was assessed. RESULTS: Among 61 included women (mean age 48 years), biopsy demonstrated 15 (24.6%) malignant and 46 (75.4%) benign lesions. Mean HbT was 55.3 ± 22.6 µM in benign lesions versus 85.4 ± 15.6 µM in cancers (p < .001). HbT threshold of 78.5 µM achieved sensitivity 80% (12/15) and specificity 89% (41/46) for malignancy. Across readers and patients, 197 pairs of CI BI-RADS and CI&DOT BI-RADS assessments were assigned. Adjunctive US-guided DOT achieved a net decrease in 23.5% (31/132) of suspicious (CI BI-RADS ≥ 4A) assessments of benign lesions (34 correct downgrades and 3 incorrect upgrades). 38.3% (31/81) of 4A assessments were appropriately downgraded. No cancer was downgraded to a non-actionable assessment. Interreader agreement analysis demonstrated kappa = 0.48-0.53 for CI BI-RADS and kappa = 0.28-0.44 for CI&DOT BI-RADS. CONCLUSIONS: Integration of US-guided DOT information achieved a 23.5% reduction in suspicious BI-RADS assessments for benign lesions. Larger studies are warranted, with attention to improved reader agreement.

Early Assessment Window for Predicting Breast Cancer Neoadjuvant Therapy using Biomarkers, Ultrasound, and Diffuse Optical Tomography.

PURPOSE: The purpose of the study was to assess the utility of tumor biomarkers, ultrasound (US) and US-guided diffuse optical tomography (DOT) in early prediction of breast cancer response to neoadjuvant therapy (NAT). METHODS: This prospective HIPAA compliant study was approved by the institutional review board. Forty one patients were imaged with US and US-guided DOT prior to NAT, at completion of the first three treatment cycles, and prior to definitive surgery from February 2017 to January 2020. Miller-Payne grading was used to assess pathologic response. Receiver operating characteristic curves (ROCs) were derived from logistic regression using independent variables, including: tumor biomarkers, US maximum diameter, percentage reduction of the diameter (%US), pretreatment maximum total hemoglobin concentration (HbT) and percentage reduction in HbT (%HbT) at different treatment time points. Resulting ROCs were compared using area under the curve (AUC). Statistical significance was tested using two-sided two-sample student t-test with P < 0.05 considered statistically significant. Logistic regression was used for ROC analysis. RESULTS: Thirty-eight patients (mean age = 47, range 24-71 years) successfully completed the study, including 15 HER2 + of which 11 were ER + ; 12 ER + or PR + /HER2-, and 11 triple negative. The combination of HER2 and ER biomarkers, %HbT at the end of cycle 1 (EOC1) and %US (EOC1) provided the best early prediction, AUC = 0.941 (95% CI 0.869-1.0). Similarly an AUC of 0.910 (95% CI 0.810-1.0) with %US (EOC1) and %HbT (EOC1) can be achieved independent of HER2 and ER status. The most accurate prediction, AUC = 0.974 (95% CI 0.933-1.0), was achieved with %US at EOC1 and %HbT (EOC3) independent of biomarker status. CONCLUSION: The combined use of tumor HER2 and ER status, US, and US-guided DOT may provide accurate prediction of NAT response as early as the completion of the first treatment cycle. CLINICAL TRIAL REGISTRATION NUMBER: NCT02891681. https://clinicaltrials.gov/ct2/show/NCT02891681 , Registration time: September 7, 2016.

Mentor Mothers Zithulele: exploring the role of a peer mentorship programme in rural PMTCT care in Zithulele, Eastern Cape, South Africa.

Background: The majority of global HIV infections in children under 10 years of age occur during pregnancy, delivery or breastfeeding, despite improved coverage of 'prevention of mother-to-child transmission' (PMTCT) guidelines to reduce vertical transmission. This article looks closer at one community-based peer mentorship programme [Mentor Mothers Zithulele (MMZ)] in the Eastern Cape, South Africa which aims to supplement the existing heavily burdened antenatal programmes and improve PMTCT care.Methods: Semi-structured interviews were undertaken with HIV-positive women participating in MMZ and women receiving standard PMTCT care without any intervention. A focus group discussion (FGD) was conducted with women working as Mentor mothers (MMs) for MMZ to explore their experience of the impact of peer mentoring on the rural communities they serve.Results: Six main themes were identified in the interviews with antenatal patients: (i) MMs were a key educational resource, (ii) MMs were important in promoting exclusive breastfeeding, (iii) encouraging early HIV testing during pregnancy and (iv) providing psychosocial support to patients in their homes, thereby reducing stigma and sense of alienation. Respondents requested (v) additional focus on HIV education. MMs can (vi) function as a link between patients and health-care providers, improving treatment adherence. During the FGD two themes emerged; MMs fill the gap between patients and health services, and MMZ should focus on HIV awareness and stigma reduction.Conclusion: Peer mentoring programmes can play an important role in reducing vertical HIV transmission in resource-limited, rural settings by providing participants with education, psychosocial support, and a continuum of care.

Making Breast Screening Convenient: a Community-Based Breast Screening Event During a Historically Black University's Homecoming Festivities.

A breast screening event was conducted during the homecoming festivities of a historically Black university located in a rural county in Mississippi. Two healthcare providers performed clinical breast exams for 26 African American women during the event. This was a prime opportunity to make breast screening accessible for non-elderly African American women.

A Case Study of an Effective and Sustainable Antiretroviral Therapy Program in Rural South Africa.

The delivery of high-quality HIV care in rural settings is a global challenge. Despite the successful expansion of antiretroviral therapy (ART) in Africa, viral load (VL) monitoring and ART adherence are poor, especially in rural communities. This article describes a case study of an ART program in the deeply rural Eastern Cape of South Africa. The Zithulele ART Program initiated five innovations over time: (1) establishing district hospital as the logistical hub for all ART care in a rural district, (2) primary care clinic delivery of prepackaged ART and chronic medications for people living with HIV (PLH), (3) establishing central record keeping, (4) incentivizing VL monitoring, and (5) providing hospital-based outpatient care for complex cases. Using a pharmacy database, on-time VL monitoring and viral suppression were evaluated for 882 PLH initiating ART in the Zithulele catchment area in 2013. Among PLH initiating ART, 12.5% (n = 110) were lost to follow-up, 7.7% (n = 68) transferred out of the region, 10.2% (n = 90) left the program and came back at a later date, and 4.0% (n = 35) died. Of the on-treatment population, 82.9% (n = 480/579) had VL testing within 7 months and 92.6% (n = 536/579) by 1 year. Viral suppression was achieved in 85.2% of those tested (n = 457/536), or 78.9% (n = 457/579) overall. The program's VL testing and suppression rates appear about twice as high as national data and data from other rural centers in South Africa, despite fewer resources than other programs. Simple system innovations can ensure high rates of VL testing and suppression, even in rural health facilities.

Optoacoustic Breast Imaging: Imaging-Pathology Correlation of Optoacoustic Features in Benign and Malignant Breast Masses.

OBJECTIVE: Optoacoustic ultrasound breast imaging is a fused anatomic and functional modality that shows morphologic features, as well as hemoglobin amount and relative oxygenation within and around breast masses. The purpose of this study is to investigate the positive predictive value (PPV) of optoacoustic ultrasound features in benign and malignant masses. SUBJECTS AND METHODS: In this study, 92 masses assessed as BI-RADS category 3, 4, or 5 in 94 subjects were imaged with optoacoustic ultrasound. Each mass was scored by seven blinded independent readers according to three internal features in the tumor interior and two external features in its boundary zone and periphery. Mean and median optoacoustic ultrasound scores were compared with histologic findings for biopsied masses and nonbiopsied BI-RADS category 3 masses, which were considered benign if they were stable at 12-month follow-up. Statistical significance was analyzed using a two-sided Wilcoxon rank sum test with a 0.05 significance level. RESULTS: Mean and median optoacoustic ultrasound scores for all individual internal and external features, as well as summed scores, were higher for malignant masses than for benign masses (p < 0.0001). High external scores, indicating increased hemoglobin and deoxygenation and abnormal vessel morphologic features in the tumor boundary zone and periphery, better distinguished benign from malignant masses than did high internal scores reflecting increased hemoglobin and deoxygenation within the tumor interior. CONCLUSION: High optoacoustic ultrasound scores, particularly those based on external features in the boundary zone and periphery of breast masses, have high PPVs for malignancy and, conversely, low optoacoustic ultrasound scores have low PPV for malignancy. The functional component of optoacoustic ultrasound may help to overcome some of the limitations of morphologic overlap in the distinction of benign and malignant masses.

Downgrading and Upgrading Gray-Scale Ultrasound BI-RADS Categories of Benign and Malignant Masses With Optoacoustics: A Pilot Study.

OBJECTIVE: False-positive findings remain challenging in breast imaging. This study investigates the incremental value of optoacoustic imaging in improving BI-RADS categorization of breast masses at ultrasound. SUBJECTS AND METHODS: The study device is an optoacoustic breast imaging device with a handheld duplex laser and internal gray-scale ultrasound probe, fusing functional and morphologic information (optoacoustic ultrasound). In this prospective multisite study, breast masses assessed as BI-RADS category 3, 4A, 4B, 4C, or 5 by site radiologists underwent both gray-scale ultrasound and optoacoustic imaging with the study device. Independent reader radiologists assessed internal gray-scale ultrasound and optoacoustic ultrasound features for each mass and assigned a BI-RADS category. The percentage of mass reads for which optoacoustic ultrasound resulted in a downgrade or upgrade of BI-RADS category relative to internal gray-scale ultrasound was determined. RESULTS: Of 94 total masses, 39 were biopsy-proven malignant, 44 were biopsy-proven benign, and 11 BI-RADS category 3 masses were stable at 12-month follow-up. The sensitivity of both optoacoustic ultrasound and internal gray-scale ultrasound was 97.1%. The specificity was 44.3% for optoacoustic ultrasound and 36.4% for internal gray-scale ultrasound. Using optoacoustic ultrasound, 41.7% of benign masses or BI-RADS category 3 masses that were stable at 12-month follow-up were downgraded to BI-RADS category 2 by independent readers; 36.6% of masses assigned BI-RADS category 4A were downgraded to BI-RADS category 3 or 2, and 10.1% assigned BI-RADS category 4B were downgraded to BI-RADS category 3 or 2. Using optoacoustic ultrasound, independent readers upgraded 75.0% of the malignant masses classified as category 4A, 4B, 4C, or 5, and 49.4% of the malignant masses were classified as category 4B, 4C, or 5. CONCLUSION: Optoacoustic ultrasound resulted in BI-RADS category downgrading of benign masses and upgrading of malignant masses compared with gray-scale ultrasound.

American College of Radiology Accreditation, Performance Metrics, Reimbursement, and Economic Considerations in Breast MR Imaging.

Accreditation through the American College of Radiology (ACR) Breast Magnetic Resonance Imaging Accreditation Program is necessary to qualify for reimbursement from Medicare and many private insurers and provides facilities with peer review on image acquisition and clinical quality. Adherence to ACR quality control and technical practice parameter guidelines for breast MR imaging and performance of a medical outcomes audit program will maintain high-quality imaging and facilitate accreditation. Economic factors likely to influence the practice of breast MR imaging include cost-effectiveness, competition with lower-cost breast-imaging modalities, and price transparency, all of which may lower the cost of MR imaging and allow for greater utilization.

Disorder in the Court: Cluster B Personality Disorders in United States Case Law.

Previous research has shown that antisocial, borderline, narcissistic and histrionic personality disorders, also known as the Cluster B personality disorders in the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (DSM-5), are commonly raised in lawsuits. Cluster B disorders are characterized by problems with emotion regulation, impulsivity and interpersonal conflicts. Without question, individuals diagnosed with a Cluster B disorder possess traits that make them more susceptible to becoming involved in litigation; however, to date there has been no research on how the disorders interact with the judicial system. This study surveyed litigant success of Cluster B personality disorders in United States federal and state case law. Results showed that both criminal and civil litigants tended to be unsuccessful in their cases. Overall, this study demonstrated that court opinions can provide a window into the psychology of trial litigants and how personality can affect trial outcomes.

A Pivotal Study of Optoacoustic Imaging to Diagnose Benign and Malignant Breast Masses: A New Evaluation Tool for Radiologists.

Purpose To compare the diagnostic utility of an investigational optoacoustic imaging device that fuses laser optical imaging (OA) with grayscale ultrasonography (US) to grayscale US alone in differentiating benign and malignant breast masses. Materials and Methods This prospective, 16-site study of 2105 women (study period: 12/21/2012 to 9/9/2015) compared Breast Imaging Reporting and Data System (BI-RADS) categories assigned by seven blinded independent readers to benign and malignant breast masses using OA/US versus US alone. BI-RADS 3, 4, or 5 masses assessed at diagnostic US with biopsy-proven histologic findings and BI-RADS 3 masses stable at 12 months were eligible. Independent readers reviewed US images obtained with the OA/US device, assigned a probability of malignancy (POM) and BI-RADS category, and locked results. The same independent readers then reviewed OA/US images, scored OA features, and assigned OA/US POM and a BI-RADS category. Specificity and sensitivity were calculated for US and OA/US. Benign and malignant mass upgrade and downgrade rates, positive and negative predictive values, and positive and negative likelihood ratios were compared. Results Of 2105 consented subjects with 2191 masses, 100 subjects (103 masses) were analyzed separately as a training population and excluded. An additional 202 subjects (210 masses) were excluded due to technical failures or incomplete imaging, 72 subjects (78 masses) due to protocol deviations, and 41 subjects (43 masses) due to high-risk histologic results. Of 1690 subjects with 1757 masses (1079 [61.4%] benign and 678 [38.6%] malignant masses), OA/US downgraded 40.8% (3078/7535) of benign mass reads, with a specificity of 43.0% (3242/7538, 99% confidence interval [CI]: 40.4%, 45.7%) for OA/US versus 28.1% (2120/7543, 99% CI: 25.8%, 30.5%) for the internal US of the OA/US device. OA/US exceeded US in specificity by 14.9% (P < .0001; 99% CI: 12.9, 16.9%). Sensitivity for biopsied malignant masses was 96.0% (4553/4745, 99% CI: 94.5%, 97.0%) for OA/US and 98.6% (4680/4746, 99% CI: 97.8%, 99.1%) for US (P < .0001). The negative likelihood ratio of 0.094 for OA/US indicates a negative examination can reduce a maximum US-assigned pretest probability of 17.8% (low BI-RADS 4B) to a posttest probability of 2% (BI-RADS 3). Conclusion OA/US increases the specificity of breast mass assessment compared with the device internal grayscale US alone. Online supplemental material is available for this article. © RSNA, 2017.

Predictors of aggressive response towards simulated intruders depend on context and sex in Crimson Finches (Neochmia phaeton).

Quantifying differences in aggressive behaviour across contexts can be useful in developing an understanding of life histories and breeding systems, as well as the relative costs and benefits of such behaviour. We investigated whether age, relative body size and colouration, sex, and breeding stage influenced levels of aggressive behaviour in two contexts, towards conspecific and heterospecific intruders (mounts) around active nests of group living Crimson Finches (Neochmia phaeton). We found that when responding to a conspecific mount, relative body size, and age were important in predicting the aggressive response of males toward a conspecific, with older males and those close in size to their opponent showing a higher aggressive response. On the other hand, factors relating to female aggression were not as clear. In contrast, response to a heterospecific mount was unrelated to age, colour or size in either sex. Additionally, although birds were equally aggressive to conspecific and heterospecific mount types, we found no evidence that individuals are consistent in their level of aggression across these contexts. This suggests that aggressive behaviour in Crimson Finches is at least partially plastic and that individuals may be capable of assessing and responding to situations independently.