Jennifer A. Clarke

Microhabitat Use of Deer Mice: Effects of Interspecific Interaction Risks

Microhabitat use by deer mice ( Peromyscus maniculatus ) was tested under five different simulated moonlight intensities, using an indoor habitat chamber with shrub covered areas and open areas, and food sources. Tests were run in the presence and absence of a potential competitor, Ords kangaroo rat ( Dipodomys ordii ). From tracks in the sand, we determined that, when alone, deer mice decreased total activity as moonlight increased and were more active in areas with cover than in open areas. However, deer mice did not vary proportions of activity allocated to open areas (ca. 20%) and cover/edge areas (ca. 80%) with variations in moonlight. Deer mice consumed more seeds in areas with cover but also did not vary the proportions of seeds eaten in the open (ca. 43%) or cover (ca. 57%) with variations in moonlight. Using infrared video filming, we determined that deer mice increased use of cover to nearly 100% in the presence of Ords kangaroo rats. Aggression (active chasing and locking fights) by kangaroo rats towards deer mice caused this shift. Our experiments substantiate field observations of variable microhabitat use by deer mice in areas with and without kangaroo rats and identify behavioral interactions involved.

NORTH AMERICAN ELK BUGLE VOCALIZATIONS: MALE AND FEMALE BUGLE CALL STRUCTURE AND CONTEXT

Abstract Bugle calls of male North American elk (Cervus elaphus) are common sounds during fall in the Canadian and United States Rocky Mountains. In contrast, bugle calls of female elk are rarely heard. We quantified the acoustic structure of elk bugle calls, which is an essential 1st step to understanding of the function of the call. We also investigated whether motivation–structural rules apply to these long-distance calls. We measured male elk bugle calls in Rocky Mountain National Park, Colorado, during autumn of 1998 and 1999 and we measured female elk bugle calls on 2 Colorado elk ranches (private establishments that raise elk for commercial purposes) during spring of 2001 and 2002. All bugle calls had 3 segments: on-glide, whistle, and off-glide. Male bugle calls were longer in duration than female bugle calls (P < 0.01). Bugle calls emitted in aggressive interactions had 4 or 5 low-frequency formants, resulting in harsher, wider bandwidth bugles (P < 0.001) compared to the tonal calls emitted in nonaggressive contexts, which lacked formants. Thus, elk bugle calls appear to conform to motivation–structural rules.

Dingo (Canis lupus dingo) acoustic repertoire: form and contexts

The classification and description of a species’ acoustic repertoire is critical to our understanding of broader behavioural patterns and provides data for future cross-species comparative studies. To date, our understanding of canid auditory communication remains limited as full acoustic repertoires have been compiled for only nine of 36 extant species. Dingoes (Canis lupus dingo) are apex predators in Australia, and while their ecology and life-history patterns have been extensively studied, their communication system remains poorly understood. Early studies noted four sound types, but whether this represented the dingoes’ full range of laryngeal and nasal sounds was unknown. We aimed to quantitatively and qualitatively describe the full acoustic repertoire of dingoes. We identified nine discrete vocalisations (i.e., laryngeal sounds) and two nasal sounds. Of these nine vocalisations, five were previously identified as common to other canid species. This study also revealed that dingoes possess a graded acoustic communication system, where the gradual change in acoustic characteristics of discrete vocalisations was noted. Dingoes also uttered ‘mixed sounds’, a finding in concordance with previous studies of social canids. Additionally, we established an ethogram to further our understanding of the contexts in which dingo acoustic communication occurs.

SIGNATURE CHARACTERISTICS IN CONTACT CALLS OF THE WHITE-NOSED COATI

Abstract “Chirp” calls of adult white-nosed coatis (Nasua narica) were measured and compared to determine form and function of these frequently emitted vocalizations. Behavioral contexts during vocalizations were documented, and chirp calls were tape recorded and analyzed using a digital spectrograph. Also, a bat detector was used to determine whether ultrasonic frequencies were emitted in chirps. Duration of the chirp calls was 0.146–0.202 s. Spectrogram analyses revealed that the lowest frequencies of the chirps averaged 4.66–11.83 kHz and that the highest frequencies averaged 1417.66 kHz. Ultrasonic frequencies (30–55 kHz) also were detected in chirp calls. Chirps differed among individuals regarding the differential frequency between the 1st and 2nd resonance bars (P ≤ 0.01). Chirps seem to function as contact calls for this social mammal because they were emitted only while coatis were moving. The short duration and high frequency of the calls may allow for contact with nearby group members while minimizing auditory detection by predators. Unique features of each coatis chirp also may allow individual recognition.

The influence of spring snow depth on white-tailed Ptarmigan breeding success in the Sierra Nevada

The relationship between spring snow depth and breeding success of an introduced population of White-tailed Ptarmigan (Lagopus leucurus altipetens) in the Sierra Nevada, California, was studied from 1982 through 1987. Yearly spring snow depth varied from 50.8 cm to 424.2 cm. Hatch dates were later in years of deep snow (P < 0.05) but brood size showed no relation to snow depth. Nesting success, chick survival, and brood success (all of which contribute to breeding success) were negatively correlated with snow depth as was breeding success (P < 0.05). The number of paired ptarmigan in the study area varied from 22 (in 1987) to 46 in 1985 which was the year with the least snow; however, no significant relationship existed between breeding numbers and snow depth. Successful reproduction of White-tailed Ptarmigan in the Sierra Nevada appears to be strongly affected by snow, potentially due to its influence on the availability of resources such as nest sites, food, and cover.

ACOUSTIC CHARACTERISTICS OF WHITE-NOSED COATI VOCALIZATIONS: A TEST OF MOTIVATION-STRUCTURAL RULES

Abstract Vocalizations of white-nosed coatis (Nasua narica) emitted in nonaggressive and aggressive contexts were measured and compared to determine if these calls exhibited acoustic characteristics in accordance with motivation-structural (MS) rules. “Chirp” and “squawk” calls were compared spectrographically using 11 coatis from 3 zoos. Chirps were short-duration (68.6–212.0 ms), high–maximum frequency (16.2–17.9 kHz), tonal calls with frequency modulations. Squawks were longer-duration (177.9–546.5 ms), low–maximum frequency (8.4–13.2 kHz), wide-bandwidth calls with 6 resonances and little frequency modulation. Squawks differed from chirps in duration, maximum frequency, and change in frequency (P < 0.001). Chirps were emitted during nonaggressive behaviors, whereas squawks were emitted during agonistic encounters. Squawks conformed to MS rule predictions for aggressive calls, and chirps supported MS rule predictions for nonaggressive contexts, but some exceptional characteristics were noted in chirps. Many chirps (67.7%) concluded with a short-duration, broad-bandwidth sound with high energy in low frequencies, and may represent variations of a graded call.

Biogeography of white-tailed ptarmigan (Lagopus leucurus) : implications from an introduced population in the Sierra Nevada

The alpine community of the Sierra Nevada, California, U.S.A., presents a unique set of biogeographic questions in that numerous cosmopolitan species and species present in other North American cordillera are absent in this range. The white-tailed ptarmigan (Lagopus leucurus (Richardson) is a primary alpine species that was historically absent in the Sierra Nevada until seventy-two birds were introduced in 1971-72 from the Rocky Mountains, Colorado, U.S.A. This study investigates whether ptarmigan could have once inhabited the Sierra Nevada and later become extinct in the range or if the species never successfully colonized the Sierra Nevada. The strongest argument for the former absence of this species in the Sierra Nevada is that barriers east and north prevented the birds from colonizing the range. Pollen records and fossil evidence indicate that the Great Basin presented this terrestrial alpine species with many dispersal barriers between the Rocky Mountains and the Sierra Nevada. From the Mid-Pleistocene to the present, barriers in the Great Basin have existed in forms ranging from extensive woodlands and great pluvial lakes to deserts. From the Pleistocene to the present, the principle barriers to ptarmigan movements from the north were the Columbia River and its gorge and the relatively low altitude of the South Cascades which provide a paucity of suitable alpine

Aggressive Bimodal Communication in Domestic Dogs, Canis familiaris.

Evidence of animal multimodal signalling is widespread and compelling. Dogs’ aggressive vocalisations (growls and barks) have been extensively studied, but without any consideration of the simultaneously produced visual displays. In this study we aimed to categorize dogs’ bimodal aggressive signals according to the redundant/non-redundant classification framework. We presented dogs with unimodal (audio or visual) or bimodal (audio-visual) stimuli and measured their gazing and motor behaviours. Responses did not qualitatively differ between the bimodal and two unimodal contexts, indicating that acoustic and visual signals provide redundant information. We could not further classify the signal as ‘equivalent’ or ‘enhancing’ as we found evidence for both subcategories. We discuss our findings in relation to the complex signal framework, and propose several hypotheses for this signal’s function.

Concatenation of 'alert' and 'identity' segments in dingoes' alarm calls.

Multicomponent signals can be formed by the uninterrupted concatenation of multiple call types. One such signal is found in dingoes, Canis familiaris dingo. This stereotyped, multicomponent ‘bark-howl’ vocalisation is formed by the concatenation of a noisy bark segment and a tonal howl segment. Both segments are structurally similar to bark and howl vocalisations produced independently in other contexts (e.g. intra- and inter-pack communication). Bark-howls are mainly uttered in response to human presence and were hypothesized to serve as alarm calls. We investigated the function of bark-howls and the respective roles of the bark and howl segments. We found that dingoes could discriminate between familiar and unfamiliar howl segments, after having only heard familiar howl vocalisations (i.e. different calls). We propose that howl segments could function as ‘identity signals’ and allow receivers to modulate their responses according to the caller’s characteristics. The bark segment increased receivers’ attention levels, providing support for earlier observational claims that barks have an ‘alerting’ function. Lastly, dingoes were more likely to display vigilance behaviours upon hearing bark-howl vocalisations, lending support to the alarm function hypothesis. Canid vocalisations, such as the dingo bark-howl, may provide a model system to investigate the selective pressures shaping complex communication systems.

Climates of Communication: Collegiality, Affect, Spaces and Attitudes in Peer Review

This chapter explores communication between university teachers in the context of peer review. Narrative data from in-depth one-on-one interviews and open questionnaires were used by the authors to examine specific experiences that teachers in the study identified as impacting on the quality of peer-to-peer interactions. The findings indicate that collegiality, affect, attitude and spaces are central to the ways in which the teachers communicated with each other to create constructive opportunities for learning. The outcomes from the research are helpful to anyone considering the use of peer review as an approach to enhancing learning and teaching in the University sector.