Gail Patricelli | University of California, Davis (original) (raw)

Papers by Gail Patricelli

The Journal of experimental biology, Jan 20, 2015

Animals selectively direct their visual attention toward relevant aspects of their environments. ... more Animals selectively direct their visual attention toward relevant aspects of their environments. They can shift their attention using a combination of eye, head, and body movements. While we have a growing understanding of eye and head movements in mammals, we know little about these processes in birds. We therefore measured the eye and head movements of freely-behaving Indian peafowl (Pavo cristatus) using a telemetric eye-tracker. Both eye and head movements contributed to gaze changes in peafowl. When gaze shifts were smaller, eye movements played a larger role than when gaze shifts were larger. The duration and velocity of eye and head movements were positively related to the size of the eye and head movements, respectively. In addition, the coordination of eye and head movements in peafowl differed from mammals; peafowl exhibited a near absence of the vestibulo-ocular reflex, which may partly result from the peafowl's ability to move their heads as quickly as their eyes.

Female preference favors the evolution of elaborate male display traits in many species. However,... more Female preference favors the evolution of elaborate male display traits in many species. However, little is known about whether this process of sexual selection also favors males with better courtship skills, such as the ability to respond to female signals. Here we used a robotic female to determine experimentally whether male Sage Grouse, Centrocercus urophasianus, adjust their display behavior in response to female signals and whether more responsive males are more successful in courtship.Our experiment involved two treatments in which the robot imitated natural female signals of interest or disinterest in courting males. In the interested treatment, the robot remained upright and looked side to side. In the disinterested treatment, the robot pecked at the ground as if foraging. We then compared the male display behavior before and during the experimental treatments.Key male display behaviors such as strut behavior, position of the fembot, and display rate were measured. We predi...

The Auk, 2015

Although birds are generally known for their vocally produced songs and calls, some species have ... more Although birds are generally known for their vocally produced songs and calls, some species have evolved alternate means of acoustic communication that do not require the syrinx. While many of these mechanical sounds are used in a courtship context, the importance of among-and within-individual variation in these sounds is almost entirely unknown. We investigated feather-produced sounds in male Greater Sage-Grouse (Centrocercus urophasianus), which congregate on leks during the spring breeding season and perform elaborate displays to attract females. Despite decades of research on the vocal components of the display, the frequency-modulated and mechanically generated ''swish'' sounds remain poorly studied. We used 2 years of acoustic data to evaluate the relationship between the time and frequency characteristics of the swish display and male mating success. Although characteristics of the swish sounds showed individual-specific patterns of variation, neither univariate nor multivariate analyses revealed direct effects of the acoustic qualities of these mechanical sounds on number of copulations. However, we did find that the frequency range of individual notes was correlated with note duration, and that males who successfully copulated showed a larger frequency range for a given duration than unsuccessful males. Furthermore, successful males increased this frequency change more strongly with the approach of a female than did unsuccessful males. These results parallel previous findings that successful and unsuccessful males show different patterns of adjustment with changing courtship conditions. Our results emphasize the importance of considering the interaction among multiple components of displays in analyses of mate choice, and help to broaden our understanding of the function of mechanical sounds in this and other species of birds.

Proceedings of the Royal Society B: Biological Sciences, 2010

Animals in many vertebrate species vocalize in response to predators, but it is often unclear whe... more Animals in many vertebrate species vocalize in response to predators, but it is often unclear whether these antipredator calls function to communicate with predators, conspecifics or both. We evaluated the function of antipredator calls in 10 species of passerines by measuring the acoustic directionality of these calls in response to experimental presentations of a model predator. Acoustic directionality quantifies the radiation pattern of vocalizations and may provide evidence about the receiver of these calls. We predicted that antipredator calls would have a lower directionality if they function to communicate with surrounding conspecifics, and a higher directionality and aimed at the receiver if they function to communicate with the predator. Our results support both of these functions. Overall, the birds produce antipredator calls that have a relatively low directionality, suggesting that the calls radiate in many directions to alert conspecifics. However, birds in some species increase the directionality of their calls when facing the predator. They can even direct their calls towards the predator when facing lateral to it-effectively vocalizing sideways towards the predator. These results suggest that antipredator calls in some species are used to communicate both to conspecifics and to predators, and that birds adjust the directionality of their calls with remarkable sophistication according to the context in which they are used.

Behavioral Ecology and Sociobiology, 2007

Studies of animal acoustic communication have found that the frequency and temporal structure of ... more Studies of animal acoustic communication have found that the frequency and temporal structure of acoustic signals can be shaped by selection for efficient communication. The directionality of acoustic radiation may also be adapted for communication, but we know relatively little about how directionality varies with signal function, sender morphology, and the environment in which the sound is transmitted. We tested the hypothesis that the directionality of a vocalization is adapted to its function in communication. This hypothesis predicts that vocalizations that are directed to multiple conspecifics (e.g., advertisements and alarms) will be relatively omnidirectional because this will maximize the number of neighbors and mates that receive the signal, and that vocalizations directed to particular individuals will be relatively directional because this will maximize detection of the signal by the targeted receiver and minimize eavesdropping. To test these predictions, we measured the directionality and amplitude of red-winged blackbird (Agelaius pheoniceus) vocalizations in the field by recording vocalizations simultaneously on eight calibrated microphones encircling the bird. We found significant variation in directionality among vocalizations. Supporting our predictions, we found that the most omnidirectional vocalizations were those used to alert conspecifics to danger, and the most directional vocal-izations are those used during courtship and solicitation of copulation, when the costs of eavesdropping are likely to be high. These results suggest that the directionality of redwinged blackbird vocalizations is shaped by selection for effective communication. This study is the first to provide statistical support for the hypothesis that directionality is related to the function of a signal in communication.

The Auk, 2007

The potential for diff erences between genetic paternity and paternity inferred from behavioral o... more The potential for diff erences between genetic paternity and paternity inferred from behavioral observation has long been recognized. These diff erences are associated with the challenge for females of seeking both genetic and material benefi ts; this challenge is less severe in species with polygynous, non-resource-based mating systems (such as leks) than in those with resource-based systems. We present the fi rst study of paternity patt erns in a non-resource-based species that does not form true leks. We compared paternity inferred from observed mating behavior to genetically assigned paternity in the Satin Bowerbird (Ptilonorhynchus violaceus) using eight microsatellite markers. Mating behavior was observed and recorded via automated video-cameras positioned at all bowers (29-34 bowers each year) in the study site throughout each mating season. We obtained blood samples and identifi ed mothers for 11 chicks in 9 nests. For all chicks, the most likely genetic father had been observed to mate with the mother in the year the chick was sampled. All most likely genetic fathers were assigned with high confi dence and all were bowerholding males. These results demonstrate that genetic paternity can be inferred from observed mating behavior with reasonable confi dence in Satin Bowerbirds. Observed male mating-success is therefore a reliable predictor of reproductive success, and this suggests that high skew in observed male mating-success translates directly to high skew in reproductive success.

Animal Behaviour, 2008

Sound waves typically radiate from a vocalizing animal with unequal amplitude in different direct... more Sound waves typically radiate from a vocalizing animal with unequal amplitude in different directions; this may profoundly affect communication, favouring adaptations that use or compensate for this directionality. Previous studies suggest that variation in directionality among vocalization types is related to function, with vocalizations such as alerts being relatively omnidirectional, thus maximizing the number of surrounding receivers, and vocalizations such as courtship calls being relatively directional, thus reducing eavesdropping by beaming sounds at the targeted receiver. Here we examine variation within a vocalization type, bird songs, to test hypotheses about how variation in song directionality relates to singing behaviour and the social context of singing. We measured the directionality and amplitude of red-winged blackbird songs in the field using calibrated microphones encircling the bird. We found variation in directionality among song types, possibly allowing males to select songs from their repertoires with directionality to suit the social context. We found support for the hypothesis that the amplitude and directionality of songs are related, with more-directional songs delivered at higher amplitudes. In addition, we found support for the hypothesis that directionality is negatively related to the degree of male rotation on the perch between vocalizations, suggesting that males may combine omnidirectional songs and rotation to broadcast their songs, and may face the receiver and produce directional songs during direct interactions. We also observed variation in directionality among note types within songs. These results suggest that directionality plays an important role in shaping song structure and singing behaviour in red-winged blackbirds.

Economists study negotiation as a series of events-partner choice, information gathering, bargain... more Economists study negotiation as a series of events-partner choice, information gathering, bargaining, etc.-with each step of the process affecting the outcome of the next, and the optimal decision at each stage depending on the player's bargaining power. The context in which these negotiations occur-the market-is critical, since players can adjust their behaviors in response to outside offers. Animals similarly are faced with sequential decisions regarding courtship: who to court, how to approach a potential mate, at what level to display, when to give up, etc. Thus economic models of negotiation in a market provide a framework in which we can view not just the outcome of courtship (assortative mating), but also the process, where each sex can use tactics to improve their negotiating outcome, using the assets that they have available. Here we propose to use negotiation as a conceptual framework to explore the factors promoting tactical adjustments during sequential stages of courtship in lekking species. Our goal is to discuss the utility of negotiation as a heuristic tool, as well as the promise and peril of co-opting game theoretic models from economics to understand animal interactions. We will provide a brief overview of a few areas where we see promise for using negotiation as a framework to understand animal courtship dynamics: choice of a display territory, tactical partner choice for negotiation, approaching a potential partner and courtship haggling [Current Zoology 57 (2): 225-236, 2011].

The Journal of the Acoustical Society of America, 2012

ABSTRACT Acoustic sensor arrays can allow researchers to localize the position of vocalizing anim... more ABSTRACT Acoustic sensor arrays can allow researchers to localize the position of vocalizing animals. During the course of research on a threatened bird species, the greater sage-grouse, we developed a 24-channel wired array to non-invasively monitor male courtship displays at traditional display grounds (i.e. leks). Here we describe a study in which we localized repeated playbacks of four local species while varying speaker position, the number and arrangement of microphones, and accuracy of speed of sound and sensor location estimates. As expected, localization accuracy was lowest when the speaker was outside the array and when using a linear microphone arrangements. We found no overall effect of species identity in spite of strong differences in time and frequency structure of the playbacks, although we did find significant interactions of species with other factors in our analysis. Simulated errors in speed-of-sound-in-air and estimation of sensor position revealed that while localization was most accurate when these errors were small, localization was still possible even with relatively large errors in these two factors. While we hope these results will help researchers to design effective sensor arrays, specific outcomes will depend on study-specific factors as well as the specific sound processing and localization algorithms employed.

Behaviour

Lekking male greater sage-grouse (Centrocercus urophasianus) compete with neighbours not only by ... more Lekking male greater sage-grouse (Centrocercus urophasianus) compete with neighbours not only by strutting to attract females but also by directly challenging other males. These challenges include approaching another male and adopting an anti-parallel orientation at close quarters ('facing past encounter') and fighting, in which the birds strike one another with their wings. Facing past encounters and facing past encounters that led to fights in free-living sage-grouse were videotaped and analysed to test predictions arising from two sets of hypotheses to account for the features of such encounters. They could be used to assess or threaten opponents (index signal or threat signal hypotheses) or they may be the result of a stalemate in which one bird's attempts to gain an vantage point for attack are neutralised by counter moves by the other bird (combat hypothesis). Frame-by-frame analyses of both facing past encounters and fights were used to extract data to test specif...

Journal of Applied Ecology

Summary1. Animals produce sounds for diverse biological functions such as defending territories, ... more Summary1. Animals produce sounds for diverse biological functions such as defending territories, attracting mates, deterring predators, navigation, finding food and maintaining contact with members of their social group. Biologists can take advantage of these acoustic behaviours to gain valuable insights into the spatial and temporal scales over which individuals and populations interact. Advances in bioacoustic technology, including the development of autonomous cabled and wireless recording arrays, permit data collection at multiple locations over time. These systems are transforming the way we study individuals and populations of animals and are leading to significant advances in our understandings of the complex interactions between animals and their habitats.2. Here, we review questions that can be addressed using bioacoustic approaches, by providing a primer on technologies and approaches used to study animals at multiple organizational levels by ecologists, behaviourists and ...

Proceedings. Biological sciences / The Royal Society, Jan 7, 2014

Studies of sexual signalling generally focus on interactions between dyadic pairs, yet communicat... more Studies of sexual signalling generally focus on interactions between dyadic pairs, yet communication in natural populations often occurs in the context of complex social networks. The ability to survey social environments and adjust signal production appropriately should be a critical component of success in these systems, but has rarely been documented empirically. Here, we used autonomous recording devices to identify 118 472 songs produced by 26 male common yellowthroats (Geothlypis trichas) over two breeding seasons, coupled with detailed surveys of social conditions on each territory. We found strong evidence that common yellowthroat males adjusted their total song production in response to both changes in within-pair social context and changes in the fertility of neighbouring females up to 400 m away. Within the social pair, males drastically reduced their song production when mated, but the magnitude of this reduction depended on both the time of day and on the fertility stat...

Nature, Jan 17, 2002

Models of sexual selection generally assume that behavioural courtship displays reflect intrinsic... more Models of sexual selection generally assume that behavioural courtship displays reflect intrinsic male qualities such as condition, and that males display with maximum intensity to attract females to mate. Here we use robotic females in a field experiment to demonstrate that male satin bowerbirds (Ptilonorhynchus violaceus) do not always display at maximum intensity - rather, successful males modulate their displays in response to signals from females. Our results indicate that sexual selection may favour those males that can produce intense displays but which know how to modify these according to the female response.

Recent research has demonstrated that noise from natural gas development negatively impacts sage-... more Recent research has demonstrated that noise from natural gas development negatively impacts sage-grouse abundance, stress levels, and behaviors. Other types of anthropogenic noise sources are similar to gas-development noise and, thus, the response by sage-grouse is likely to be similar. The results of research suggest that effective management of the natural soundscape is critical to the conservation and protection of sage-grouse. The goals of this review are to discuss current approaches in the management of new and existing noise sources in Wyoming and recommend research priorities for establishing effective noise management strategies. We make 4 interim recommendations: (1) that noise-management objectives should be set relative to typical ambient noise levels in sage-grouse habitat before development; the best currently available measuremenet of residual noise levels levels (L 90) in undisturbed areas suggest an ambient level of 16 to 20 dBA; (2) that an increase in median nois...

Ornithological Monographs, 2012

Anthropogenic noise can limit the ability of birds to communicate by masking their acoustic signa... more Anthropogenic noise can limit the ability of birds to communicate by masking their acoustic signals. Masking, which reduces the distance over which the signal can be perceived by a receiver, is frequency dependent, so the different notes of a single song may be masked to different degrees. We analyzed the individual notes of mating vocalizations produced by Greater Sage-Grouse (Centrocercus urophasianus) and noise from natural gas infrastructure to quantify the potential for such noise to mask Greater Sage-Grouse vocalizations over both long and short distances. We found that noise produced by natural gas infrastructure was dominated by low frequencies, with substantial overlap in frequency with Greater Sage-Grouse acoustic displays. Such overlap predicted substantial masking, reducing the active space of detection and discrimination of all vocalization components, and particularly affecting low-frequency and low-amplitude notes. Such masking could increase the difficulty of mate assessment for lekking Greater Sage-Grouse. We discuss these results in relation to current stipulations that limit the proximity of natural gas infrastructure to leks of this species on some federal lands in the United States. Significant impacts to Greater Sage-Grouse populations have been measured at noise levels that predict little or no masking. Thus, masking is not likely to be the only mechanism of noise impact on this species, and masking analyses should therefore be used in combination with other methods to evaluate stipulations and predict the effects of noise exposure.

Journal of Experimental Biology, 2009

Greater sage-grouse, Centrocercus urophasianus, have been a model system in studies of sexual sel... more Greater sage-grouse, Centrocercus urophasianus, have been a model system in studies of sexual selection and lek evolution. Mate choice in this species depends on acoustic displays during courtship, yet we know little about how males produce these sounds. Here we present evidence for previously undescribed two-voiced sound production in the sage-grouse. We detected this ʻdouble whistleʼ (DW) using multi-channel audio recordings combined with video recordings of male behavior. Of 28 males examined, all males produced at least one DW during observation; variation in DW production did not correlate with observed male mating success. We examined recordings from six additional populations throughout the speciesʼ range and found evidence of DW in all six populations, suggesting that the DW is widespread. To examine the possible mechanism of DW production, we dissected two male and female sage-grouse; the syrinx in both sexes differed noticeably from that of the domestic fowl, and notably had two sound sources where the bronchi join the syrinx. Additionally, we found males possess a region of pliable rings at the base of the trachea, as well as a prominent syringeal muscle that is much reduced or absent in females. Experiments with a live phonating bird will be necessary to determine how the syrinx functions to produce the whistle, and whether the DW might be the result of biphonation of a single sound source. We conclude that undiscovered morphological and behavioral complexity may exist even within well-studied species, and that integrative research approaches may aid in the understanding of this type of complexity.