A parametric model for estimating prevalence,incidence, and mean bout duration from point sampling

Point or instantaneous sampling refers to the scoring of presence or absence of behavior at the end of equally spaced intervals of time and is used to estimate prevalence. The literature cited demonstrates that point sampling does not adequately estimate frequency or mean bout duration. A parametric model is developed based on exponentially distributed times of behavior and intervening nonbehavior, thus enabling estimators of mean bout length and incidence. Variance estimators are provided and a method is suggested for designing sample situations which control the variance of the prevalence estimator. The paper concludes the theoretical investigation with a thorough Monte Carlo investigation and application to a “real-life” problem. The point sample estimators compare favorably with continuous observation under appropriate choice of sampling interval and under approximately exponential assumptions.     

高海拔地区昆明野生动物园大熊猫春季刻板行为探究

2011年2月26日～5月2日,在高海拔地区昆明云南野生动物园,采用连续记录法(Continuous recording) 和焦点动物取样法(Focal animal sampling)记录与分析了3只亚成年雌性大熊猫昼间刻板行为发生频次和持续时间,并就温度、游客流量与刻板行为发生的相关性进行了初步探讨.结果表明,大熊猫刻板行为发生频次(次·h-1)高峰和持续时间( min·h-1)较长的高峰均出现在10:00～11:00和16:00～17:00,各时段行为表达水平存在极显著差异(x2=61.183,P＜0.01;x2 =56.470,P＜0.01).个体间刻板行为持续时间昼间分布无显著差异(x2=3.185,P＞0.05);个体间发生频次在14:00～15:00时段存在显著差异(x2=7.796,P＜0.05),而在其他时段则存在极显著差异(x2=11.536 ～20.212,P＜0.01).温度与刻板行为发生频次、持续时间均无显著相关性(rx=-0.067,P＞0.05;rs=-0.012,P＞0.05);游客流量与持续时间、发生频次有一定的正相关,但不显著(rs =0.187,P＞0.05;rs=0.159,P＞0.05).此外,在刻板行为型时间分配格局中,以刻板踱步最高,占56.78％,其次为爬笼、吮掌,而旋转、摇摆及坐着旋转等其他刻板行为表现较少,其总和仅占1.20％.     

Field Cricket Species Differences in the Temporal Patterns of Long-Distance Mate Attraction Signals

We quantify variation in the temporal components of long‐distance mate attraction signals produced by a North American field cricket, Gryllus rubens Scudder. Total signaling time, trilling bout duration, and hourly bout number exhibit high repeatability within individuals. Extensive variation exists across individuals: some males never signal while others signal for several hours each night; of the signalers, average trilling bout duration ranges from <1 min to well over an hour; some males produce only one trilling bout in an evening while others produce three bouts every 2 h. Body size, weight, wing morphology, and condition do not appear to explain the variation. We compare the temporal signaling components of G. rubens with its sister species, G. texensis. Although G. rubens produce slightly more trills per hour with slightly shorter trilling bout durations, the temporal components of these long‐distance mate attraction signals are surprisingly similar across species.     

Does fear beget fear? Risk-mediated habitat selection triggers predator avoidance at lower trophic levels

Seasonal changes in weather and food availability differentially impact energy budgets of small mammals such as bats. While most thermal physiological research has focused on species that experience extreme seasonal temperature variations, knowledge is lacking from less variable temperate to subtropical climates. We quantified ambient temperature (T _a) and skin temperature (T _sk) responses by individuals from a population of New Zealand lesser short-tailed bats (Mystacina tuberculata) during summer and winter using temperature telemetry. During summer, communal roosts were more thermally stable than T _a. During winter, solitary roosts were warmer than T _a indicating significant thermal buffering. Communal roost trees were used on 83 % of observation days during summer, and individuals occupying them rarely entered torpor. Solitary roosts were occupied on 93 % of observation days during winter, and 100 % of individuals occupying them used torpor. During summer and winter, bats employed torpor on 11 and 95 % of observation days, respectively. Maximum torpor bout duration was 120.8 h and winter torpor bout duration correlated negatively with mean T _a. Torpor bout duration did not differ between sexes, although female minimum T _sk was significantly lower than males. The summer Heterothermy Index varied, and was also significantly affected by T _a. Mean arousal time was correlated with sunset time and arousals occurred most frequently on significantly warmer evenings, which are likely associated with an increased probability of foraging success. We provide the first evidence that torpor is used flexibly throughout the year by M. tuberculata, demonstrating that roost choice and season impact torpor patterns. Our results add to the growing knowledge that even small changes in seasonal climate can have large effects on the energy balance of small mammals.     

滇金丝猴雌性个体间的理毛行为

相互理毛行为广泛存在于社会性群居灵长类动物中,通常具有清洁卫生和社会交往功能。2012 年10 月至2013 年6 月,我们在云南白马雪山国家级自然保护区对一人工辅助投食滇金丝猴群,采用全事件取样法和焦点动物取样法收集了雌性个体间相互理毛的行为数据,包括理毛的部位、理毛的姿势、理毛的时间和回合数。研究结果表明:滇金丝猴雌性个体之间每次相互理毛的平均时间为5. 7 min。相互理毛部位较多的发生在自我理毛不能进行(达到)的部位(61.1% );在不能自我理毛部位的相互理毛行为持续时间长,平均9.7 min;在个体能够进行自我理毛部位的相互理毛持续时间短,平均为3. 2 min。相互理毛的姿势以对坐为主(48. 4% ),不同理毛姿势的理毛时间差异显著。新迁入家庭单元的雌性个体为理毛的首先发起者,但其获得被理毛的时间却并不多。滇金丝猴雌性个体相互理毛部位、理毛姿势和理毛时间的差异表明,它们之间的相互理毛行为符合卫生功能假说和社会功能假说。     

Inbreeding,energy use and sexual signaling

Genetic quality and energy metabolism are expected to have an effect on the level of energetically costly sexual signaling. To explore this we manipulated genetic quality of male decorated crickets (Gryllodes sigillatus) by inbreeding and measured the resting metabolic rate and total energy budget of males. We also measured several aspects of the sexual signaling of males: probability to initiate calling, latency, amount of call bouts, first call bout duration, mean call bout duration and total time spent calling. Inbreeding increased the latency and lowered the first and mean call bout duration. Moreover, the resting metabolic rate had a positive effect, and body mass a negative effect on first call bout duration and mean call bout duration. Our results, suggest that sexual signals are indicative of genetic quality but are also dependent on the physical properties of individuals.     

Analysis of the Optimal Duration of Behavioral Observations Based on an Automated Continuous Monitoring System in Tree Swallows (Tachycineta bicolor): Is One Hour Good Enough?

Studies of animal behavior often rely on human observation, which introduces a number of limitations on sampling. Recent developments in automated logging of behaviors make it possible to circumvent some of these problems. Once verified for efficacy and accuracy, these automated systems can be used to determine optimal sampling regimes for behavioral studies. Here, we used a radio-frequency identification (RFID) system to quantify parental effort in a bi-parental songbird species: the tree swallow (Tachycineta bicolor). We found that the accuracy of the RFID monitoring system was similar to that of video-recorded behavioral observations for quantifying parental visits. Using RFID monitoring, we also quantified the optimum duration of sampling periods for male and female parental effort by looking at the relationship between nest visit rates estimated from sampling periods with different durations and the total visit numbers for the day. The optimum sampling duration (the shortest observation time that explained the most variation in total daily visits per unit time) was 1h for both sexes. These results show that RFID and other automated technologies can be used to quantify behavior when human observation is constrained, and the information from these monitoring technologies can be useful for evaluating the efficacy of human observation methods.     

Social behaviour of the calves of semi-wild Maremma cattle,Bos primigenius taurus

The social behaviour of semi-wild free-ranging Maremma calves, Bos primigenius taurus, was observed daily in their first 2 months from birth at the estate La Trappola (Ponticelli Reserve), 10 Km south-west of Grosseto, Tuscany, Italy. In the first 2–3 days of life the calves hid in the maquis, while the cows grazed in the surrounding area. The time spent at close range to the cows decreased with the increase in the age of the calves, but the time spent far from the mother was always greater than that spent at close or intermediate ranges. Lying down was the dominant activity at a distance over 15 m from the mother, while the time spent in standing still decreased daily. The daily mean of the minutes spent by the calves with their peers reached peaks between their 11th and 40th days of life. Sucking bouts reached a peak between 09.00 and 10.00 h, after the herd reached the grazing area from the night dormitory. Another peak occurred between 15.00 and 16.00 h. Calves solicited and terminated sucking bouts spontaneously more than cows. The mean duration of each sucking bout increased with calf age, but was negatively correlated with the mean daily number of sucking bouts. Immediately before or after a sucking bout, cows mainly sniffed their calves in the muzzle and tail area. Calves sniffed and licked the cows mainly in the area of the udder. Play activity reached a peak in the early morning, decreased strongly at mid-day and increased again in mid-afternoon. Grazing, and to a lesser extent moving to and from the pasture land, were the most frequent activities occurring before and after play. Frontal pushes were the most preferred kind of play by both females and males. Female calves soliciting play in males showed significantly more “frontal pushing” than “non-reproductive mounts”. The male calves were more often initiators of play than were females.     

Ambulatory Blood Pressure Monitoring: Importance of Sampling Rate and Duration—48 Versus 24 Hours—on the Accurate Assessment of Cardiovascular Risk

Independent prospective studies have found that ambulatory blood pressure (BP) monitoring (ABPM) is more closely correlated with target organ damage and cardiovascular disease (CVD) risk than clinic BP measurement. This is based on studies in which BP was sampled every 15–30?min for ≤24?h, without taking into account that reproducibility of any estimated parameter from a time series to be potentially used for CVD risk assessment might depend more on monitoring duration than on sampling rate. Herein, we evaluated the influence of duration (48 vs. 24?h) and sampling rate of BP measurements (form every 20–30?min up to every 2?h) on the prognostic value of ABPM-derived parameters. We prospectively studied 3344 subjects (1718 men/1626 women), 52.6?±?14.5 yrs of age, during a median follow-up of 5.6 yrs. Those with hypertension at baseline were randomized to ingest all their prescribed hypertension medications upon awakening or ≥1 of them at bedtime. At baseline, BP was measured at 20-min intervals from 07:00 to 23:00?h and at 30-min intervals at night for 48?h, and physical activity was simultaneously monitored every min by wrist actigraphy to accurately derive the awake and asleep BP means. Identical assessment was scheduled annually and more frequently (quarterly) if treatment adjustment was required. ABPM profiles were modified to generate time series of identical 48-h duration but with data sampled at 1- or 2-h intervals, or shorter, i.e., first 24?h, time series with data sampled at the original rate (daytime 20-min intervals/nighttime 30-min intervals). Bland-Altman plots indicated that the range of individual differences in the estimated awake and asleep systolic (SBP) and diastolic BP (DBP) means between the original and modified ABPM profiles was up to 3-fold smaller for data sampled every 1?h for 48?h than for data sampled every 20–30?min for the first 24?h. Reduction of ABPM duration to just 24?h resulted in error of the estimated asleep SBP mean, the most significant prognostic marker of CVD events, in the range of ?21.4 to +23.9?mm Hg. Cox proportional-hazard analyses adjusted for sex, age, diabetes, anemia, and chronic kidney disease revealed comparable hazard ratios (HRs) for mean BP values and sleep-time relative BP decline derived from the original complete 48-h ABPM profiles and those modified to simulate a sampling rate of one BP measurement every 1 or 2?h. The HRs, however, were markedly overestimated for SBP and underestimated for DBP when the duration of ABPM was reduced from 48 to only 24?h. This study on subjects evaluated prospectively by 48-h ABPM documents that reproducibility in the estimates of prognostic ABPM-derived parameters depends markedly on duration of monitoring, and only to a lesser extent on sampling rate. The HR of CVD events associated with increased ambulatory BP is poorly estimated by relying on 24-h ABPM, indicating ABPM for only 24?h may be insufficient for proper diagnosis of hypertension, identification of dipping status, evaluation of treatment efficacy, and, most important, CVD risk stratification. (Author correspondence: rhermida@uvigo.es)     

Species Richness-Environment Relationships of European Arthropods at Two Spatial Grains: Habitats and Countries

We study how species richness of arthropods relates to theories concerning net primary productivity, ambient energy, water-energy dynamics and spatial environmental heterogeneity. We use two datasets of arthropod richness with similar spatial extents (Scandinavia to Mediterranean), but contrasting spatial grain (local habitat and country). Samples of ground-dwelling spiders, beetles, bugs and ants were collected from 32 paired habitats at 16 locations across Europe. Species richness of these taxonomic groups was also determined for 25 European countries based on the Fauna Europaea database. We tested effects of net primary productivity (NPP), annual mean temperature (T), annual rainfall (R) and potential evapotranspiration of the coldest month (PET_min) on species richness and turnover. Spatial environmental heterogeneity within countries was considered by including the ranges of NPP, T, R and PET_min. At the local habitat grain, relationships between species richness and environmental variables differed strongly between taxa and trophic groups. However, species turnover across locations was strongly correlated with differences in T. At the country grain, species richness was significantly correlated with environmental variables from all four theories. In particular, species richness within countries increased strongly with spatial heterogeneity in T. The importance of spatial heterogeneity in T for both species turnover across locations and for species richness within countries suggests that the temperature niche is an important determinant of arthropod diversity. We suggest that, unless climatic heterogeneity is constant across sampling units, coarse-grained studies should always account for environmental heterogeneity as a predictor of arthropod species richness, just as studies with variable area of sampling units routinely consider area.     

Dive bout organization in the Chinstrap penguin at seal island, antarctica

Diving behavior of 2 breeding Chinstrap penguins (Pygoscelis antarctica) was studied focusing first and primarily on dive bouts rather than dives themselves. Analysis of dive bout organization revealed (1) though there are differences between solitary dives and dive bouts in dive duration and dive depth, the first dives of dive bouts do not differ from solitary dives in the dive parameters, (2) mean dive duration during bout correlates positively to both mean dive depth during bout and mean surface interval during bout, while number of dives during bout negatively correlates to both cost (consumed energy) and duration of a dive cycle during bout. These findings suggest the following possibilities on foraging behavior of penguins: (1) their decision to repeat diving depends on the result of the first dive at a site, and the first dives of bouts would tend to be searching or evaluating dives though they would be also successful foraging dives, (2) they repeat diving at a foraging patch until foraging efficiency decrease to a threshold of diminishing returns.     

Evaluation of a Low-Cost Electrostatic Dust Fall Collector for Indoor Air Endotoxin Exposure Assessment

Exposure to endotoxin in home environments has become a key issue in asthma and allergy research. Most studies have analyzed floor or mattress dust endotoxin, but its validity as a proxy for airborne exposure is unknown, while active airborne dust sampling is not feasible in large-scale population studies because of logistic and financial limitations. We therefore developed and evaluated a simple passive airborne dust collection method for airborne endotoxin exposure assessment. We explored an electrostatic dust fall collector (EDC), consisting of a 42- by 29.6-cm-sized folder with four electrostatic cloths exposed to the air. The EDC was tested during two 14-day periods in seven nonfarm and nine farm homes and in farm stables. In parallel, active airborne dust sampling was performed with Harvard impactors and floor dust collected by vacuuming, using nylon sampling socks. The endotoxin levels could be measured in all EDC cloth extracts. The levels (in EU/m²) between EDCs used simultaneously or in different sampling periods in the same home correlated strongly (r > 0.8). EDC endotoxin also correlated moderately to strongly (r = 0.6 to 0.8) with the endotoxin measured by active airborne dust sampling and living room floor dust sampling and—in farm homes—with the endotoxin captured by the EDC in stables. In contrast, endotoxin levels measured by floor dust sampling showed only a poor correlation with the levels measured by active airborne dust sampling. We therefore conclude that measuring endotoxin levels with the EDC is a valid measure of average airborne endotoxin exposure, while reproducibility over time is at least equivalent to that of reservoir dust analyses.     

Temporal and Individual Variation in Offspring Provisioning by Tree Swallows: A New Method of Automated Nest Attendance Monitoring

Studies of the ecology and evolution of avian nesting behavior have been limited by the difficulty and expense of sampling nest attendance behavior across entire days or throughout a substantial portion of the nestling period. Direct observation of nesting birds using human observers and most automated devices requires sub-sampling of the nestling period, which does not allow for the quantification of the duration of chick-feeding by parents within a day, and may also inadequately capture temporal variation in the rate at which chicks are fed. Here I describe an inexpensive device, the Automated Perch Recorder (APR) system, which collects accurate, long-term data on hourly rates of nest visitation, the duration of a pair''s workday, and the total number of visits the pair makes to their nest across the entire period for which it is deployed. I also describe methods for verifying the accuracy of the system in the field, and several examples of how these data can be used to explore the causes of variation in and tradeoffs between the rate at which birds feed their chicks and the total length of time birds spend feeding chicks in a day.     

Fights at the Dinner Table: Agonistic Behavior in Pachydiplax longipennis (Odonata: Libellulidae) at Feeding Sites

Aggressive behavior of Pachydiplax longipennis during foraging was quantified by observing focal individuals on arrays of artificial perches. Pachydiplax apparently aggressively defend, for up to several hours at a time, one or a few feeding perches. Seventeen percent of all behaviors included agonistic actions, e.g., chasing or physical contact. The frequency of interactions was correlated positively with ambient temperature, solar radiation, prey density and density of other dragonflies. Both sexes initiated and responded to intra- and interspecific aggression; intraspecific interactions were more intense, however. Males had significantly higher interaction rates and fighting success than females, and intraspecific male–male contests were particularly intense. When prey were visibly localized, contest winners commonly gained perches closer to the prey swarm, and aggressive behavior was apparently correlated with feeding opportunity. Despite the frequency of aggression, these dragonflies allocated only about 19 s, on average, to agonistic behavior during 30-min observation periods. This and other costs appear small compared to foraging benefits of occupying a favorable perch, although at a very high interaction intensity high energy costs and lower intake reduce the net energy gain.     

Predation selects for low resting metabolic rate and consistent individual differences in anti-predator behavior in a beetle

Significant between-individual variation in resting metabolic rate (RMR) of animals is a widespread phenomenon that may have important implications for our understanding of variation in behavior and animal personality. By using wild caught mealworm beetles, Tenebrio molitor, we examined the relationships among survival rate under predator tests, individual response latency time to become immobile under the risk of predation, duration of immobility time, and RMR. Individuals with higher levels of RMR were bold, and bold individuals were found to be more exposed to the risk of bird predation. We found that RMR was positively correlated with the latency of immobility response and negatively correlated with the total duration of immobility. The correlation between behavioral responses suggests a behavioral syndrome in the anti-predator behavior of T. molitor. The results indicate that energy metabolism may be part of a syndrome that involves behavior and life history traits in animals.     

Effects of Variations in Daylength and Temperature on Net Rates of Photosynthesis, Dark Respiration, and Excretion by Isochrysis galbana Parke

The effects of variable daylength and temperature on net rates of photosynthesis, dark respiration, and excretion of a unicellular marine haptophyte, Isochrysis galbana Parke, were examined and related to division rates. Six combinations of daylength (18:6, 12:12, 6:18 light:dark, LD) and temperature (20, 25 C) were used. Daily rates of net photosynthesis were closely correlated to division rates, suggesting a direct relationship, and were maximal when cells were grown at 12:12 LD at both temperatures and 18:6 LD at 20 C. A daylength of 6 hours decreased daily rates by decreasing the time for carbon uptake. Further, cells grown with this daylength had maximal chlorophyll a contents, suggesting a physiological adaptation by photosynthetic units to short light periods. A photoperiod of 18:6 LD at 25 C decreased daily rates of net photosynthesis by reducing the hourly rate of net photosynthesis via an unidentified mechanism. The importance of rates of net dark respiration in controlling daily net photosynthesis was small, with carbon lost during dark periods varying between 4 and 14% of that gained during light periods. Also, the influence of net excretion was small, varying between 1.0 and 5.5% of daily net photosynthesis.     

Heart rate and extrasystolic arrhythmias in active subjects aged over 90. A chronobiological study

We analyzed the circadian rhythm of heart rate (HR), of simple atrial premature beats (APB) and of simple ventricular premature beats (VPB) in very old subjects undergoing dynamic ECG for 24 h. The 18 subjects under study (11 women and 7 men) were aged 90 or more (mean +/- SD 92.3 +/- 2.3, range 90-98), did not complain of acute cardiac pathologies, were not taking any medication and were synchronized as to time schedules. The mean duration of DECG recording was of 23 h and 54 min. The collection of data concerning the hourly mean of HR (6 ten-sec samples taken every 10 min) and of the number/hour of APB and VPB was carried out manually. A significant rhythm (single cosinor) was detected for heart rate in 14 subjects out of 18 and in the group (population cosinor); it was also detected for APB (9 subjects out of 15) and for VPB (5 subjects out of 15) also by the single cosinor. It was not detected for the group (population cosinor). No significant correlations, either direct or inverted, were revealed between HR and premature beats. We demonstrate therefore that, even in very old subjects, the circadian rhythm of HR still exists as in younger subjects.     

Recolonizing carnivores: Is cougar predation behaviorally mediated by bears?

Conservation and management efforts have resulted in population increases and range expansions for some apex predators, potentially changing trophic cascades and foraging behavior. Changes in sympatric carnivore and dominant scavenger populations provide opportunities to assess how carnivores affect one another. Cougars (Puma concolor) were the apex predator in the Great Basin of Nevada, USA, for over 80 years. Black bears (Ursus americanus) have recently recolonized the area and are known to heavily scavenge on cougar kills. To evaluate the impacts of sympatric, recolonizing bears on cougar foraging behavior in the Great Basin, we investigated kill sites of 31 cougars between 2009 and 2017 across a range of bear densities. We modeled the variation in feeding bout duration (number of nights spent feeding on a prey item) and the proportion of primary prey, mule deer (Odocoileus hemionus), in cougar diets using mixed‐effects models. We found that feeding bout duration was driven primarily by the size of the prey item being consumed, local bear density, and the presence of dependent kittens. The proportion of mule deer in cougar diet across all study areas declined over time, was lower for male cougars, increased with the presence of dependent kittens, and increased with higher bear densities. In sites with feral horses (Equus ferus), a novel large prey, cougar consumption of feral horses increased over time. Our results suggest that higher bear densities over time may reduce cougar feeding bout durations and influence the prey selection trade‐off for cougars when alternative, but more dangerous, large prey are available. Shifts in foraging behavior in multicarnivore systems can have cascading effects on prey selection. This study highlights the importance of measuring the impacts of sympatric apex predators and dominant scavengers on a shared resource base, providing a foundation for monitoring dynamic multipredator/scavenger systems.     

Orthophosphate influx and efflux rates of Chlorella fusca measured in a continuous turbidostat culture with 32P under various conditions

The main objective of the experiments with Chlorella fusca strain 211-8b was to measure, with adequate time resolution, the unidirectional influx rates of phosphate into non-phosphate-starved algae under different steady state conditions (light, temperature, 3-phosphoglycerate influence) or following the addition of several photosynthesis and phosphate transport inhibitors (phenylmercuric acetate, p-chloromercuribenzoate, arsenate). the algae were cultivated in a phosphate rich medium in a continuous turbidostat culture. The phosphate exchange experiments with carrier-free ³²PO ₄ ^3- were performed directly in the continuous culture. The sampling intervals after the tracer addition were 15 s.For a continuous steady state culture grown in the light (25° C) the unidirectional influx rate measured with ³²P is 260 times higher than the net uptake rate (=influx minus efflux rate) calculated from the mass balance using the data of this culture. In all experiments, except the control experiment with trichloroacetic acid killed cells, the specific activity of the intracellular inorganic orthophosphate compartment oscillates around a constant mean value which never reaches the specific activity of the nutrient medium within the duration of the short-term experiments (7.5 min). The inhibitors strongly affect the characteristics of the oscillations. The unidirectional influx rates are constant. Oscillating flushing rates with unlabelled phosphate from a storage compartment have been postulates to explain the oscillations. Oscillating rates from the individual cells are apparently synchronized by an unknown mechanism.     

Incubation feeding by male Scarlet Tanagers: a mate removal experiment

ABSTRACT Incubation feeding, where males feed their mates, is a common behavior in birds and may improve female condition, nest attentiveness, and nesting success. We used behavioral observations and a temporary mate removal experiment to test the female nutrition hypothesis for incubation feeding by male Scarlet Tanagers (Piranga olivacea). All males (N= 20) were observed incubation feeding and fed females both at the nest (x? 1.36 trips/h) and away from the nest (x? 20.1 trips/h). Male feeding rate off‐nest was negatively correlated with the duration of female foraging bouts and positively correlated with the total time females spent incubating per hour. Eggs were predated at seven of 19 (37%) nests, but nest survival during incubation was not related to either female incubation behavior or male feeding rate. During temporary removal experiments (N= 12), female Scarlet Tanagers remained on the nest significantly longer and did not have longer foraging bouts. An unexpected outcome of the removal experiments was a dramatic change in female vocal behavior. All 12 experimental females gave chik‐burr calls during the male‐removal experiments (x? bout length = 11.7 min), but during normal observation periods only six of 20 females at the incubation stage gave chik‐burr calls (x? bout length = 0.7 min, N= 20). Our results suggest that female tanagers likely gain nutritional benefits from incubation feeding, but male feeding may not improve immediate reproductive success. Nine of 54 (17%) nestlings in five of 17 broods (29%) were extra‐pair young (EPY), indicating that males could potentially benefit from incubation feeding via mate retention and fidelity as well as, or instead of, through immediate gains in reproductive success. Our study indicates that females benefit from incubation feeding and do not simply passively accept food from their mates, but instead may influence male feeding rates through direct (e.g., mate following and vocalizing) and indirect (the threat of mate abandonment or cuckoldry) means.