Marcelo Araya-Salas

University of Costa Rica | UCR · Centro de Investigación en Neurociencias (CIN)

The ability of an animal to detect environmental cues is crucial for its survival and fitness. In bats, sound certainly plays a significant role in the search for food, spatial navigation, and social communication. Yet, the efficiency of bat’s echolocation could be limited by atmospheric attenuation and background clutter. In this context, sound ca...

Animal acoustic signals are widely used in diverse research areas due to the relative ease with which sounds can be registered across a wide range of taxonomic groups and research settings. However, bioacoustics research can quickly generate large data sets, which might prove challenging to analyze promptly. Although many tools are available for th...

Traits that exhibit differences between the sexes have been of special interest in the study of phenotypic evolution. Classic hypotheses explain sexually dimorphic traits via intra-sexual competition and mate selection, yet natural selection may also act differentially on the sexes to produce dimorphism. Natural selection can act either through phy...

El canto cumple un importante rol en la ecología y comportamiento de las aves. Entender los procesos que alteran la producción y transmisión del canto es fundamental para dilucidar su respuesta a cambios en el ambiente. En este contexto, los ambientes urbanos representan sistemas de estudio útiles para entender esta adaptación. Examinamos la estruc...

Roosts are vital for the survival of many species, and how individuals choose one site over another is affected by various factors. In bats, for example, species may use stiff roosts such as caves or compliant ones such as leaves; each type requires not only specific morphological adaptations but also different landing manoeuvres. Selecting a suita...

Abstract.- Variation in song structure of the Rufous-collared Sparrow (Zonotrichia capensis) along an urban gradient in southwestern Peru Song plays a crucial role in bird ecology and behavior, and understanding the processes that alter the production and transmission of song is fundamental to elucidate its response to changes in the environment. I...

Roosts are vital for the survival of many species, and how individuals choose one site over another is affected by various ecological factors. Biomechanical constraints could also affect roost selection, particularly in volant taxa that require sites with easy access, thereby reducing costs (i.e., predation, accidents). To date, no studies have est...

Roosts are vital for the survival of many species, and how individuals choose one site over another is affected by various ecological factors. Biomechanical constraints could also affect roost selection, particularly in volant taxa that require sites with easy access, thereby reducing costs (i.e., predation, accidents). To date, no studies have est...

Historically, bird song complexity was thought to evolve primarily through sexual selection on males; yet, in many species, both sexes sing and selection pressure on both sexes may be broader. Previous research suggests competition for mates and resources during short, synchronous breeding seasons leads to more elaborate male songs at high, tempera...

Historically, bird song complexity was thought to evolve primarily through sexual selection on males, yet in many species both sexes sing. Previous research suggests competition for mates and resources during short, synchronous breeding seasons leads to more elaborate male songs at high latitudes. In contrast, we expect male-female song dimorphism...

Assessing diversity of discretely varying behavior is a classical ethological problem. In particular, the challenge of calculating an individuals’ or species’ vocal repertoire size is often an important step in ecological and behavioral studies, but a reproducible and broadly applicable method for accomplishing this task is not currently available....

Animals produce a wide array of sounds with highly variable acoustic structures. It is possible to understand the causes and consequences of this variation across taxa with phylogenetic comparative analyses. Acoustic and evolutionary analyses are rapidly increasing in sophistication such that choosing appropriate acoustic and evolutionary approache...

Many animals produce coordinated signals, but few are more striking than the elaborate male-female vocal duets produced by some tropical songbirds. Yet, little is known about the factors driving the extreme levels of vocal coordination between mated pairs in these taxa. We examined evolutionary patterns of duet coordination and their potential evol...

Vocal signals mediate social relationships, and among networks of territorial animals, information is often shared via broadcast vocalizations. Anthropogenic noise may disrupt communication among individuals within networks, as animals change the way they vocalize in noise. Furthermore, constraints on signal transmission, including frequency maskin...

We investigated the ontogenetic changes of two call types, the inquiry call and the response call, which comprise an interactive communication system in Spix's disc-winged bats, Thyroptera tricolor. We documented structural changes on both inquiry and response calls during ontogeny by recording single individual vocalizations in a flight cage and t...

Despite longstanding interest in the evolutionary origins and maintenance of vocal learning, we know relatively little about how social dynamics influence vocal learning processes in natural populations. The “signaling group membership” hypothesis proposes that socially learned calls evolved and are maintained as signals of group membership. Howeve...

An increasing number of studies report coordinated chick provisioning by avian parents. Although the pattern of parental coordination varies across species, broad occurrence of this coordination suggests that it has an adaptive value: it may increase individual fitness via higher offspring survival, faster offspring growth rate and/or higher body r...

Vocal learning, in which animals modify their vocalizations based on social experience, has evolved in several lineages of mammals and birds, including humans. Despite much attention, the question of how this key cognitive trait has evolved remains unanswered. The motor theory for the origin of vocal learning posits that neural centres specialized...

Cognitive abilities are pivotal to the performance of traits that are closely related to fitness. However, the selective regimes shaping the evolution of cognition, and differences in individual cognitive performance under different environmental conditions have been poorly studied. The rich environmental heterogeneity and biodiversity in the Neotr...

Exchange of vocal signals is an important aspect of animal communication. Although birdsong is the premier model for understanding vocal development, the development of vocal interaction rules in birds and possible parallels to humans have been little studied. Many tropical songbirds engage in complex vocal interactions in the form of duets between...

Advanced cognitive abilities have long been hypothesized to be important in mating. Yet, most work on sexual selection has focused on morphological traits and its relevance for cognitive evolution is poorly understood. We studied the spatial memory of lekking long-billed hermits (Phaethornis longirostris) and evaluated its role in lek territory own...

Pair collaborative behavior may play an important role in avian reproduction. However, evidence for this mainly comes from certain ecological groups (e.g. passerines). We studied the coordination of parents in foraging and its effect on food provisioning rate and chick growth in a small seabird, the Dovekie (Little auk, Alle alle). The species exhi...

The study of animal acoustic signals is a central tool for many fields in ecology and evolution, but the diversity of analytical methods and sources of animal sound recordings poses important challenges for carrying out robust acoustic analyses. Sound file compression and background noise may both affect acoustic analysis, although little attention...

When using signals to attract mates or defend resources, animals often overlap the voices of other individuals in close proximity. In such contexts signal masking is likely and animals would benefit by adopting behavioural strategies that modify the timing of signals to minimize the negative effects of masking or take advantage of its signalling va...

Although song development in songbirds has been much studied as an analogue of language development in humans, the development of vocal interaction rules has been relatively neglected in both groups. Duetting avian species provide an ideal model to address the acquisition of interaction rules as duet structure involves time and pattern-specific rel...

Animal acoustic communication is one of the most fruitful research areas in behavioral and evolutionary biology. Work in this area depends largely on quantifying the structure of acoustic signals, which has often depended upon closed-source or graphical user interface (GUI) based software. 2.Here we describe the R package warbleR, a new package for...

We present an interdisciplinary effort to record feeding behaviors and control the diet of a hummingbird species (Phaethornis longirostris, the long-billed hermit or LBH) by developing a Radio Frequency Identification (RFID) based smart feeder. The system contains an RFID reader, a microcontroller, and a servo-controlled hummingbird feeder opener;...

Learning has been traditionally though to accelerate the evolutionary change of behavioral traits. We evaluated the evolutionary rate of learned vocalizations and the interplay of morphology and ecology in the evolution of these signals. We examined contact calls of 51 species of Neotropical parrots from the tribe Arini. Parrots are ideal subjects...

In the context of global change the possible loss of biodiversity has been identified as a major concern. Biodiversity could be seriously threatened as a direct consequence of changes in availability of food, changing thermal conditions, and loss and fragmentation of habitat. Considering the magnitude of global change, an understanding of the mecha...

We use allometric analysis to explore how acoustic signals scale on individual body size and to test hypotheses about the factors shaping relationships between signals and body size. Across case studies spanning birds, crickets, tree crickets, and tree frogs, we find that most signal traits had low coefficients of variation, shallow allometric scal...

One way in which secondary sexual traits can influence differential reproductive success is by playing a key role in the outcome of direct physical contests for mates. Here we describe an undocumented trait in a species of hummingbird with a lek mating system, the Long-billed hermit (LBH, Phaethornis longirostris). The trait under consideration is...

Vocal learning in birds is typically restricted to a sensitive period early in life, with the few exceptions reported in songbirds and parrots. Here, we present evidence of open-ended vocal learning in a hummingbird, the third avian group with vocal learning. We studied vocalizations at four leks of the long-billed hermit Phaethornis longirostris d...

Predator-prey interactions occur regularly in nature; however, predation events are difficult to observe in the canopy of tropical rain forests. We describe a successful capture of a Chestnut-mandibled Toucan (Ramphastos swainsonii) by a Collared Forest-Falcon (Micrastur semitorquatus) in Carara National Park, Costa Rica. The predator-prey interact...

The nightingale, the lark ascending; the cuckoo, the dawn chorus; since ancient times man has found beauty in birdsong. It appeals to our senses. It inspires composers. But is it music?Marcelo Araya-Salas listens to the nightingale wren and tries to find out if it is singing in tune.

Signals in animal communication are commonly judged as aesthetically appealing by human standards. This is particularly common for birdsong, often equated to musical compositions. No formal test, however, has analysed their harmonic properties. Musical intervals are based on the same physical characteristics of sound that underlie animal vocal sign...