Learning Across Boundaries (LABs)

Jungle Sounds

February 2017

A Semester 2 LAB led by Professors Philip Johns and Michiel van Bruegel

The aim of the Spring Lab 2017, Jungle Sounds, is to use sound monitoring stations in the forest of Brunei (Borneo) and to collect acoustic data from various locations over the course of a week. We will analyse the sound data to ascertain whether competition among calling animals for sound frequencies conforms to similar ecological principles as competition for any other limited resource. We will also use other methodologies, such as ad lib sampling of sounds and playbacks, to ascertain the source and function of animal calls in the jungle, as well as to see how animals respond to competition among calls. We will also use camera traps to get information about the local fauna.

DATES: Saturday, 18 Feb 2017 – Sunday, 26 Feb 2017

OTHER IMPORTANT INFORMATION: This LAB will likely involve a co-pay of S$500. Financial assistance and merit-based grants are available. Please come talk to CIPE about any concerns or needs you may have. We will work with every student to ensure that finances are not a burden if you wish to participate.


Application for this LAB is closed.



This Spring LAB provides an opportunity for students to design experiments, generate and test hypotheses, and analyse data, in keeping with the goals Common Curriculum – especially the science sequence and QR. The use of R-based analysis software will further hone students’ quantitative skills originally formed in QR, not least because QR uses the programming language R in its analyses. Ultimately we hope to allow some students to go into more depth and gain more expertise in the sciences than they would otherwise.



Much but not all of the last century’s ecological theory has revolved around the idea that competition plays a large role in determining the distribution and abundance of organisms. Animals and plants compete for limited resources, and their ability to compete, combined with the availability of resources, plays a large part in which organisms we find in any location. The same could be true of sound. That is, many animals communicate through sound in order to signal territoriality, attract mates, or to communicate for a variety of other purposes. To do so effectively, several conditions must be met – including that animals use frequencies that are effective in a given environment, and that there is little interference from other organisms at those sound frequencies.

In tropical forests, some sounds carry better than others, depending on conditions such proximity to ground, canopy, or running streams and waterfalls. Many animals are quite loud, and their calls or songs drown out the sounds of other organisms. In the forests of Brunei, dozens of kinds of calls occur throughout the day, and especially in the evening, night, and early morning, including extraordinarily loud insects. For example, Crystal Yong found a burrowing cricket that sang at 115 dB in the 2015 Week 7 LAB in Brunei, about as loud as a power drill. Riede (1997) conducted a limited study of animal calls in Borneo and concluded that animals calling at dusk avoid competition by calling at different times. In essence there was temporal partitioning of calling. This finding was complicated somewhat by the presence of waterfalls. Stanley (2016) performed a more detailed analysis of the “morning chorus” of birds in Barro Colorado Island (BCI), Panama, and concluded that birds compete with orthopterans (crickets and katydids) for times and frequencies where they can be heard.

We propose to go to Kuala Belalong Field Studies Centre (KBFSC), run by the University of Brunei (UBD), in Borneo, and with the help of students, set up several sound sampling stations designed by ARBIMON (http://www.sieve-analytics.com). These stations collect recordings at regular intervals and transmit recordings through simple cell phone designs; they have been used for other, comparable projects (e.g., in Puerto Rican rainforests; Campos-Cerqueira and Aide 2016). We propose to collect sounds from a total of 12 stations, three replicates each of: stream & ridge habitats, at ground level (1-2m) and canopy level (20-30m off the ground), at each habitat. Students and we will spend the first two days of setting up recording stations, and the last two days taking them down. In the between, we will record a variety of sounds by hand, ad lib, and analyse these, so students are familiar with the analytical methodologies. We will conduct playbacks of interesting animal sounds in neutral areas, i.e., away from our recording stations, as well as collect and analyse camera trap pictures of local fauna.

We will use the software package, warblR (Araya-Salas and Smith-Vidaurre 2016), or similar R-based software, to analyse the sounds we collected from recording stations. We are particularly interested in patterns where the presence or absence of very prominent animal calls (gibbons, certain cicada or cricket species, e.g.) influences the calls of other animals. Preliminary analysis of data collected by students during the 2016 Week 7 LAB at KBFSC demonstrates a greater range of sounds when more animals are calling or singing. This finding suggests, at least in part, that frequency availability is a finite resource and animals are competing for airwaves.

We hope that the Jungle Sounds LAB will be productive enough to provide us with data suitable for a grant proposal, or if our data are robust enough, for a publishable manuscript on its own, which will include student authors. Data for the publication from BCI (Stanley et al. 2016) came from a similar study from a short class.