Standardization of Emergency Department Clinical Note Templates: A Retrospective Analysis across an Integrated Health System.

BACKGROUND AND OBJECTIVE: Clinical documentation is essential for conveying medical decision-making, communication between providers and patients, and capturing quality, billing, and regulatory measures during emergency department (ED) visits. Growing evidence suggests the benefits of note template standardization; however, variations in documentation practices are common. The primary objective of this study is to measure the utilization and coding performance of a standardized ED note template implemented across a nine-hospital health system. METHODS: This was a retrospective study before and after the implementation of a standardized ED note template. A multi-disciplinary group consensus was built around standardized note elements, provider note workflows within the electronic health record (EHR), and how to incorporate newly required medical decision-making elements. The primary outcomes measured included the proportion of ED visits using standardized note templates, and the distribution of billing codes in the 6 months before and after implementation. RESULTS: In the preimplementation period, a total of six legacy ED note templates were being used across nine EDs, with the most used template accounting for approximately 36% of ED visits. Marked variations in documentation elements were noted across six legacy templates. After the implementation, 82% of ED visits system-wide used a single standardized note template. Following implementation, we observed a 1% increase in the proportion of ED visits coded as highest acuity and an unchanged proportion coded as second highest acuity. CONCLUSION: We observed a greater than twofold increase in the use of a standardized ED note template across a nine-hospital health system in anticipation of the new 2023 coding guidelines. The development and utilization of a standardized note template format relied heavily on multi-disciplinary stakeholder engagement to inform design that worked for varied documentation practices within the EHR. After the implementation of a standardized note template, we observed better-than-anticipated coding performance.

Patient sex, racial and ethnic disparities in emergency department triage: A multi-site retrospective study.

OBJECTIVES: There is limited evidence on sex, racial, and ethnic disparities in Emergency Department (ED) triage across diverse settings. We evaluated differences in the assignment of Emergency Severity Index (ESI) by patient sex and race/ethnicity, accounting for age, clinical factors, and ED operating conditions. METHODS: We conducted a multi-site retrospective study of adult patients presenting to high-volume EDs from January 2019-February 2020. Patient-level data were obtained and analyzed from three EDs (academic, metropolitan community, and rural community) affiliated with a large health system in the Southeastern United States. For the study outcome, ESI levels were grouped into three categories: 1-2 (highest acuity), 3, and 4-5 (lowest acuity). Multinomial logistic regression was used to compare ESI categories by patient race/ethnicity and sex jointly (referent = White males), adjusted for patient age, insurance status, ED arrival mode, chief complaint category, comorbidity score, time of day, day of week, and average ED wait time. RESULTS: We identified 186,840 eligible ED visits with 56,417 from the academic ED, 69,698 from the metropolitan community ED, and 60,725 from the rural community ED. Patient cohorts between EDs varied by patient age, race/ethnicity, and insurance status. The majority of patients were assigned ESI 3 in the academic and metropolitan community EDs (61% and 62%, respectively) whereas 47% were assigned ESI 3 in the rural community ED. In adjusted analyses, White females were less likely to be assigned ESI 1-2 compared to White males although both groups were roughly comparable in the assignment of ESI 4-5. Non-White and Hispanic females were generally least likely to be assigned ESI 1-2 in all EDs. Interactions between ED wait time and race/ethnicity-sex were not statistically significant. CONCLUSIONS: This retrospective study of adult ED patients revealed sex and race/ethnicity-based differences in ESI assignment, after accounting for age, clinical factors, and ED operating conditions. These disparities persisted across three different large EDs, highlighting the need for ongoing research to address inequities in ED triage decision-making and associated patient-centered outcomes.

A Natural Language Processing and Machine Learning Approach to Identification of Incidental Radiology Findings in Trauma Patients Discharged from the Emergency Department.

STUDY OBJECTIVE: Patients undergoing diagnostic imaging studies in the emergency department (ED) commonly have incidental findings, which may represent unrecognized serious medical conditions, including cancer. Recognition of incidental findings frequently relies on manual review of textual radiology reports and can be overlooked in a busy clinical environment. Our study aimed to develop and validate a supervised machine learning model using natural language processing to automate the recognition of incidental findings in radiology reports of patients discharged from the ED. METHODS: We performed a retrospective analysis of computed tomography (CT) reports from trauma patients discharged home across an integrated health system in 2019. Two independent annotators manually labeled CT reports for the presence of an incidental finding as a reference standard. We used regular expressions to derive and validate a random forest model using open-source and machine learning software. Final model performance was assessed across different ED types. RESULTS: The study CT reports were divided into derivation (690 reports) and validation (282 reports) sets, with a prevalence of incidental findings of 22.3%, and 22.7%, respectively. The random forest model had an area under the curve of 0.88 (95% confidence interval [CI], 0.84 to 0.92) on the derivation set and 0.92 (95% CI, 0.88 to 0.96) on the validation set. The final model was found to have a sensitivity of 92.2%, a specificity of 79.4%, and a negative predictive value of 97.2%. Similarly, strong model performance was found when stratified to a dedicated trauma center, high-volume, and low-volume community EDs. CONCLUSION: Machine learning and natural language processing can classify incidental findings in CT reports of ED patients with high sensitivity and high negative predictive value across a broad range of ED settings. These findings suggest the utility of natural language processing in automating the review of free-text reports to identify incidental findings and may facilitate interventions to improve timely follow-up.

Disparities in emergency department prioritization and rooming of patients with similar triage acuity score.

BACKGROUND: We identify patient demographic and emergency department (ED) characteristics associated with rooming prioritization decisions among ED patients who are assigned the same triage acuity score. METHODS: We performed a retrospective analysis of adult ED patients with similar triage acuity, as defined as an Emergency Severity Index (ESI) of 3, at a large academic medical center, during 2019. Violations of a first-come-first-served (FCFS) policy for rooming are identified and used to create weighted multiple logistic regression models and 1:M matched case-control conditional logistic regression models to determine how rooming prioritization is affected by individual patient age, sex, race, and ethnicity after adjusting for patient clinical and time-varying ED operational characteristics. RESULTS: A total of 15,781 ED encounters were analyzed, with 1612 (10.2%) ED encounters having a rooming prioritization in violation of a FCFS policy. Patient age and race were found to be significantly associated with being prioritized in violation of FCFS in both logistic regression models. The 1:M matched model showed a statistically significant relationship between violation of rooming prioritization with increasing age in years (adjusted odds ratio [aOR] 1.009, 95% confidence interval [CI] 1.005-1.013) and among African American patients compared to Caucasians (aOR 0.636, 95% CI 0.545-0.743). CONCLUSIONS: Among ED patients with a similar triage acuity (ESI 3), we identified patient age and patient race as characteristics that were associated with deviation from a FCFS prioritization in ED rooming decisions. These findings suggest that there may be patient demographic disparities in ED rooming decisions after adjusting for clinical and ED operational characteristics.

Burn related injuries: a nationwide analysis of adult inter-facility transfers over a six-year period in the United States.

BACKGROUND: US emergency department (ED) visits for burns and factors associated with inter-facility transfer are unknown and described in this manuscript. METHODS: We conducted a retrospective analysis of burn-related injuries from 2009-2014 using the Nationwide Emergency Department Sample (NEDS), the largest sample of all-payer datasets. We included all ED visits by adults with a burn related ICD-9 code and used a weighted multivariable logistic regression model to predict transfer adjusting for covariates. RESULTS: Between 2009-2014, 3,047,701 (0.4%) ED visits were for burn related injuries. A total of 108,583 (3.6%) burn visits resulted in inter-facility transfers occurred during the study period, representing approximately 18,097 inter-facility transfers per year. Burns with greater than 10% total body surface area (TBSA) resulted in a 10-fold increase in the probability of transfer, compared to burn visits with less than 10% TBSA burns. In the multivariable model, male sex (adjusted odds ratio [aOR] 2.4, 95% CI 2.3-2.6) was associated with increased odds of transfer. Older adults were more likely to be transferred compared to all other age groups. Odds of transfer were increased for Medicare and self-pay patients (vs. private pay) but there was a significant interaction of sex and payer and the effect of insurance varied by sex. CONCLUSIONS: In a national sample of ED visits, burn visits were more than twice as likely to have an inter-facility transfer compared to the general ED patient population. Substantial sex differences exist in U.S. EDs that impact the location of care for patients with burn injuries and warrants further investigation.

Incidental Radiology Findings on Computed Tomography Studies in Emergency Department Patients: A Systematic Review and Meta-Analysis.

STUDY OBJECTIVE: An incidental finding is defined as a newly discovered mass or lesion detected on imaging performed for an unrelated reason. The identification of an incidental finding may be an opportunity for the early detection of a serious medical condition, including a malignancy. However, little is known about the prevalence of incidental findings in the emergency department (ED) setting and the strategies that can be used to mitigate the risk associated with them in the ED. This study aimed to estimate the overall prevalence of incidental findings and to summarize the currently described measures to mitigate the risks associated with incidental findings. METHODS: On November 22, 2020, a systematic literature search of PubMed, EMBASE, and Scopus was performed for studies that were published in peer-reviewed journals and reported the prevalence of incidental findings in computed tomography (CT) scans in patients in the ED. Patients who received CT scans that included the head, neck, chest, or abdomen/pelvis were included. The study characteristics, overall prevalence of incidental findings, prevalence of incidental findings by body region, and prespecified subgroups were extracted. The criteria used for risk stratification within individual studies were also extracted. Pooled estimates were calculated using a random-effects meta-analysis. RESULTS: A total of 1,385 studies were identified, and 69 studies met the inclusion criteria. The included studies represented 147,763 ED encounters or radiology reports across 16 countries, and 83% of studies were observational, cross-sectional studies. A total of 35 studies (50.7%) were in trauma patients. A large degree of heterogeneity was observed across the included studies. The overall pooled prevalence estimate for any incidental finding was 31.3% (95% confidence interval 24.4% to 39.1%). We found great variation in the methods described to mitigate the risk associated with incidental findings, including a lack of standardized risk stratification, inconsistent documentation practices, and only a small subset of studies describing prospective interventions aimed at improving the recognition and management of incidental findings from the ED. CONCLUSION: In patients in the ED receiving CT scans, incidental findings are commonly encountered across a broad range of ED chief complaints. This review highlights the existence of great heterogeneity in the definitions used to classify incidental findings. Future studies are needed to determine a clinically feasible categorization standard or terminology for commonly encountered incidental findings in the ED setting to standardize classification and documentation.

Clinical Effects of Balanced Crystalloids vs Saline in Adults With Diabetic Ketoacidosis: A Subgroup Analysis of Cluster Randomized Clinical Trials.

Importance: Saline (0.9% sodium chloride), the fluid most commonly used to treat diabetic ketoacidosis (DKA), can cause hyperchloremic metabolic acidosis. Balanced crystalloids, an alternative class of fluids for volume expansion, do not cause acidosis and, therefore, may lead to faster resolution of DKA than saline. Objective: To compare the clinical effects of balanced crystalloids with the clinical effects of saline for the acute treatment of adults with DKA. Design, Setting, and Participants: This study was a subgroup analysis of adults with DKA in 2 previously reported companion trials-Saline Against Lactated Ringer's or Plasma-Lyte in the Emergency Department (SALT-ED) and the Isotonic Solutions and Major Adverse Renal Events Trial (SMART). These trials, conducted between January 2016 and March 2017 in an academic medical center in the US, were pragmatic, multiple-crossover, cluster, randomized clinical trials comparing balanced crystalloids vs saline in emergency department (ED) and intensive care unit (ICU) patients. This study included adults who presented to the ED with DKA, defined as a clinical diagnosis of DKA, plasma glucose greater than 250 mg/dL, plasma bicarbonate less than or equal to 18 mmol/L, and anion gap greater than 10 mmol/L. Data analysis was performed from January to April 2020. Interventions: Balanced crystalloids (clinician's choice of Ringer lactate solution or Plasma-Lyte A solution) vs saline for fluid administration in the ED and ICU according to the same cluster-randomized multiple-crossover schedule. Main Outcomes and Measures: The primary outcome was time between ED presentation and DKA resolution, as defined by American Diabetes Association criteria. The secondary outcome was time between initiation and discontinuation of continuous insulin infusion. Results: Among 172 adults included in this secondary analysis of cluster trials, 94 were assigned to balanced crystalloids and 78 to saline. The median (interquartile range [IQR]) age was 29 (24-45) years, and 90 (52.3%) were women. The median (IQR) volume of isotonic fluid administered in the ED and ICU was 4478 (3000-6372) mL. Cumulative incidence analysis revealed shorter time to DKA resolution in the balanced crystalloids group (median time to resolution: 13.0 hours; IQR: 9.5-18.8 hours) than the saline group (median: 16.9 hours; IQR: 11.9-34.5 hours) (adjusted hazard ratio [aHR] = 1.68; 95% CI, 1.18-2.38; P = .004). Cumulative incidence analysis also revealed shorter time to insulin infusion discontinuation in the balanced crystalloids group (median: 9.8 hours; IQR: 5.1-17.0 hours) than the saline group (median: 13.4 hours; IQR: 11.0-17.9 hours) (aHR = 1.45; 95% CI, 1.03-2.03; P = .03). Conclusions and Relevance: In this secondary analysis of 2 cluster randomized clinical trials, compared with saline, treatment with balanced crystalloids resulted in more rapid resolution of DKA, suggesting that balanced crystalloids may be preferred over saline for acute management of adults with DKA. Trial Registration: ClinicalTrials.gov Identifiers: NCT02614040; NCT02444988.

Managing sedation in the mechanically ventilated emergency department patient: a clinical review.

Managing sedation in the ventilated emergency department (ED) patient is increasingly important as critical care unit admissions from EDs increase and hospital crowding results in intubated patients boarding for longer periods. The objectives of this review are 3-fold; (1) describe the historical perspective of how sedation of the ventilated patient has changed, (2) summarize the most commonly used sedation and analgesic agents, and (3) provide a practical approach to sedation and analgesia in mechanically ventilated ED patients. We searched PubMed using keywords "emergency department post-intubation sedation," "emergency department critical care length of stay," and "sedation in mechanically ventilated patient." The search results were limited to English language and reviewed for relevance to the subject of interest. Our search resulted in 723 articles that met the criteria for managing sedation in the ventilated ED patient, of which 19 articles were selected and reviewed. Our review of the literature found that the level of sedation and practices of sedation and analgesia in the ED environment have downstream consequences on patient care including overall patient centered outcomes even after the patient has left the ED. It is reasonable to begin with analgesia in isolation, although sedating medications should be used when patients remain uncomfortable and agitated after initial interventions are performed.

Vitamin D Deficiency and Long-Term Cognitive Impairment Among Older Adult Emergency Department Patients.

INTRODUCTION: Approximately 16% of acutely ill older adults develop new, long-term cognitive impairment (LTCI), many of whom initially seek care in the emergency department (ED). Currently, no effective interventions exist to prevent LTCI after an acute illness. Identifying early and modifiable risk factors for LTCI is the first step toward effective therapy. We hypothesized that Vitamin D deficiency at ED presentation was associated with LTCI in older adults. METHODS: This was an observational analysis of a prospective cohort study that enrolled ED patients ≥ 65 years old who were admitted to the hospital for an acute illness. All patients were enrolled within four hours of ED presentation. Serum Vitamin D was measured at enrollment and Vitamin D deficiency was defined as serum concentrations <20 mg/dL. We measured pre-illness and six-month cognition using the short form Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), which ranges from 1 to 5 (severe cognitive impairment). Multiple linear regression was performed to determine whether Vitamin D deficiency was associated with poorer six-month cognition adjusted for pre-illness IQCODE and other confounders. We incorporated a two-factor interaction into the regression model to determine whether the relationship between Vitamin D deficiency and six-month cognition was modified by pre-illness cognition. RESULTS: We included a total of 134 older ED patients; the median (interquartile range [IQR]) age was 74 (69, 81) years old, 61 (46%) were female, and 14 (10%) were nonwhite race. The median (IQR) vitamin D level at enrollment was 25 (18, 33) milligrams per deciliter and 41 (31%) of enrolled patients met criteria for vitamin D deficiency. Seventy-seven patients survived and had a six-month IQCODE. In patients with intact pre-illness cognition (IQCODE of 3.13), Vitamin D deficiency was significantly associated with worsening six-month cognition (ß-coefficient: 0.43, 95% CI, 0.07 to 0.78, p = 0.02) after adjusting for pre-illness IQCODE and other confounders. Among patients with pre-illness dementia (IQCODE of 4.31), no association with Vitamin D deficiency was observed (ß-coefficient: -0.1;, 95% CI, [-0.50-0.27], p = 0.56). CONCLUSION: Vitamin D deficiency was associated with poorer six-month cognition in acutely ill older adult ED patients who were cognitively intact at baseline. Future studies should determine whether early Vitamin D repletion in the ED improves cognitive outcomes in acutely ill older patients.

Repeated Emergency Medical Services Use by Older Adults: Analysis of a Comprehensive Statewide Database.

STUDY OBJECTIVE: The objective of this study is to characterize repeated emergency medical services (EMS) transports among older adults across a large and socioeconomically diverse region. METHODS: Using the North Carolina Prehospital Medical Information System, we analyzed the frequency of repeated EMS transports within 30 days of an index EMS transport among adults aged 65 years and older from 2010 to 2015. We used multivariable logistic regressions to determine characteristics associated with repeated EMS transport. RESULTS: During the 6-year period, EMS performed 1,711,669 transports for 689,664 unique older adults in North Carolina. Of these, 303,099 transports (17.7%) were followed by another transport of the same patient within 30 days. The key characteristics associated with an increased adjusted odds ratio of repeated transport within 30 days include transport from an institutionalized setting (odds ratio [OR] 1.42; 95% confidence interval [CI] 1.38 to 1.47), blacks compared with whites (OR 1.29; 95% CI 1.24 to 1.33), a dispatch complaint of psychiatric problems (OR 1.38; 95% CI 1.25 to 1.52), back pain (OR 1.35; 95% CI 1.26 to 1.45), breathing problems (OR 1.21; 95% CI 1.15 to 1.30), and diabetic problems (OR 1.14; 95% CI 1.06 to 1.22). Falls accounted for 15.6% of all transports and had a modest association with repeated transports (OR 1.07; 95% CI 1.00 to 1.14). CONCLUSION: More than 1 in 6 EMS transports of older adults in North Carolina are followed by a repeated transport of the same patient within 30 days. Patient characteristics and chief complaints may identify increased risk for repeated transport and suggest the potential for targeted interventions to improve outcomes and manage EMS use.

Diagnosis of Elder Abuse in U.S. Emergency Departments.

OBJECTIVES: To estimate the proportion of visits to U.S. emergency departments (EDs) in which a diagnosis of elder abuse is reached using two nationally representative datasets. DESIGN: Retrospective cross-sectional analysis. SETTING: U.S. ED visits recorded in the 2012 Nationwide Emergency Department Sample (NEDS) or the 2011 National Hospital Ambulatory Medical Care Survey (NHAMCS). PARTICIPANTS: All ED visits of individuals aged 60 and older. MEASUREMENTS: The primary outcome was elder abuse defined according to International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes. The proportion of visits with elder abuse was estimated using survey weights. Odds ratios (ORs) were calculated to identify demographic characteristics and common ED diagnoses associated with elder abuse. RESULTS: In 2012, NEDS contained information on 6,723,667 ED visits of older adults, representing an estimated 29,056,673 ED visits. Elder abuse was diagnosed in an estimated 3,846 visits, corresponding to a weighted diagnosis period prevalence of elder abuse in U.S. EDs of 0.013% (95% confidence interval (CI) = 0.012-0.015%). Neglect and physical abuse were the most common types diagnosed, accounting for 32.9% and 32.2% of cases, respectively. Multivariable analysis showed greater weighted odds of elder abuse diagnosis in women (odds ratio (OR) = 1.95, 95% CI = 1.68-2.26) and individuals with contusions (OR = 2.91, 95% CI = 2.36-3.57), urinary tract infection (OR = 2.21, 95% CI = 1.84-2.65), and septicemia (OR = 1.92, 95% CI = 1.44-2.55). In the 2011 NHAMCS dataset, no cases of elder abuse were recorded for the 5,965 older adult ED visits. CONCLUSION: The proportion of U.S. ED visits by older adults receiving a diagnosis of elder abuse is at least two orders of magnitude lower than the estimated prevalence in the population. Efforts to improve the identification of elder abuse in EDs may be warranted.

Individual recognition based on communication behaviour of male fowl.

Correctly directing social behaviour towards a specific individual requires an ability to discriminate between conspecifics. The mechanisms of individual recognition include phenotype matching and familiarity-based recognition. Communication-based recognition is a subset of familiarity-based recognition wherein the classification is based on behavioural or distinctive signalling properties. Male fowl (Gallus gallus) produce a visual display (tidbitting) upon finding food in the presence of a female. Females typically approach displaying males. However, males may tidbit without food. We used the distinctiveness of the visual display and the unreliability of some males to test for communication-based recognition in female fowl. We manipulated the prior experience of the hens with the males to create two classes of males: S(+) wherein the tidbitting signal was paired with a food reward to the female, and S (-) wherein the tidbitting signal occurred without food reward. We then conducted a sequential discrimination test with hens using a live video feed of a familiar male. The results of the discrimination tests revealed that hens discriminated between categories of males based on their signalling behaviour. These results suggest that fowl possess a communication-based recognition system. This is the first demonstration of live-to-video transfer of recognition in any species of bird.

The Effect of Community Health Center (CHC) Density on Preventable Hospital Admissions in Medicaid and Uninsured Patients.

Community health centers (CHCs) are expected to play a major role in expanding primary care access under the Affordable Care Act (ACA). Although benefits of such health centers among Medicaid populations have been documented, little is known about their impact on the uninsured. Additionally, the effect of health center density on preventable hospitalizations is unknown. This study calculated health center density within five miles of California hospitals using geocoding and Haversine distance formula. Using the 2010 California inpatient dataset, rates of preventable hospitalizations were classified by Prevention Quality Indicators (PQIs). After adjusting for patient and community covariates, we found that as health center density increased, the odds ratio of preventable hospitalizations decreased in both Medicaid and uninsured patients. (OR 0.79 and 0.86 for Medicaid and uninsured respectively p<.001,.044) These findings suggest health centers are contributing to lowering preventable hospitalizations and supports plans to expand such health centers.

Dental visits to a North Carolina emergency department: a painful problem.

BACKGROUND: Emergency departments (EDs) act as the safety net and alternative care site for patients without insurance who have dental pain. METHODS: We conducted a retrospective chart review of visits to an urban teaching hospital ED over a 12-month period, looking at patients who presented with a chief complaint or ICD code indicating dental pain, toothache, or dental abscess. RESULTS: The number of visits to this ED by patients with a dental complaint was 1,013, representing approximately 1.3% of all visits to this ED. Dental patients had a mean age of 32 (+/- 13) years, and 60% of all dental visits were made by African Americans. Dental patients were more likely to be self-pay than all other ED patients (61% versus 22%, P < 0.001). At the vast majority of dental ED visits (97%), the patient was treated and discharged; at most visits (90%) no dental procedure was performed. ED treatment typically consisted of pain control and antibiotics; at 81% of visits, the patient received an opiate prescription on discharge, and at 69% of visits, the patient received an antibiotic prescription on discharge. LIMITATIONS: This retrospective chart review covered a limited period of time, included only patients at a large urban academic medical center, and did not incorporate follow-up analysis. CONCLUSION: Although they make up a small percentage of all ED visits, dental ED visits are more common among the uninsured, seldom result in definitive care or hospital admission, and often result in prescription of an opioid or antibiotic. These findings are cause for concern and have implications for public policy.

The role of the anterior lateral eyes in the vision-based behaviour of jumping spiders.

Jumping spiders, or salticids, sample their environment using a combination of two types of eyes. The forward-facing pair of 'principal' eyes have narrow fields of view, but exceptional spatial resolution, while the two or three pairs of 'secondary' eyes have wide fields of view and function especially well as motion analysers. Motion detected by the secondary eyes may elicit an orienting response, whereupon the object of interest is examined further using the high-acuity principal eyes. The anterior lateral (AL) eyes are particularly interesting, as they are the only forward-facing pair of secondary eyes. In this study, we aimed to determine characteristics of stimuli that elicit orienting responses mediated by the AL eyes. After covering all eyes except the AL eyes, we measured orienting responses to dot stimuli that varied in size and contrast, and moved at different speeds. We found that all stimulus parameters had significant effects on orientation propensity. When tethered flies were used as prey, we found that visual information from the AL eyes alone was sufficient to elicit stalking behaviour. These results suggest that, in terms of overall visual processing, the relevance of spatial vision in the AL eyes has been underestimated in the literature. Our results also show that female spiders are significantly more responsive than males. We found that hunger caused similar increases in orientation propensity in the two sexes, but females responded more often than males both when sated and when hungry. A higher propensity by females to orient toward moving objects may be related to females tending to experience higher nutritional demands than males.

Silent tidbitting in male fowl, Gallus gallus: a referential visual signal with multiple functions.

With the notable exception of bee dances, there are no established examples of multimodal referential signals. The food calls of male fowl, Gallus gallus, are functionally referential and the acoustic component of a multimodal display. However, the specificity of the receiver's response to the visual component (tidbitting) has never been tested. Here we provide the first detailed analysis of tidbitting, and test the hypothesis that these characteristic movements are functionally referential. We conducted a playback experiment with five high-definition video stimuli: Silent tidbit, Matched-frequency motion in the opposite direction, Silent crows, Inactive male and Empty cage. Females searched for food more during Silent tidbitting than under any other condition, suggesting that this visual display specifically predicts the presence of food and hence has similar functional properties to food calls. Silent tidbitting was also singularly effective at evoking approach and close inspection, which may enhance signal memorability. These social responses suggest that the visual component of the display has the unique function of triggering assessment of signaler identity and quality as a potential mate. The acoustic and visual components are hence redundant as a food signal, but synergistic when additional functions are considered. These findings emphasize the perceptual complexity of multimodal displays and provide the first demonstration of multimodal referential signaling in a vertebrate.