SOCIAL MATCH allowed the successful development of two important tools, a scale to automatically record small animal weight and individual on-board microphones to record birds’ vocalizations. These tools allow the monitoring of individual conditions and the quantification of vocal behaviour.
The scale apparatus is a modified feeder, birds sit on a perch to eat seeds but the perch is more than a simple branch, it lays on a digital scale and it is surrounded by an antenna. Each bird has a little transponder (PIT-tag) at their leg with a unique ID, like a passport, the antenna uses radio-frequency identification (RFID) technology to receive the bird’s identity which is then registered by a logger. Both the logger and the digital scale are connected to a tiny computer (a raspberry PI) which integrates and store the information about the ID and the weight. Currently, the developed system is fully functional in controlled laboratory conditions and also recording sociable weavers’ weights in the savanna of South Africa despite the challenging climatic conditions (high temperature range and often strong winds).
Individual on-board microphones are necessary to study vocalizations of each individual in a communicating group. Like each guest of a talk show has her/his own microphone, we wanted to equip each bird of a breeding group with one. This way we know what each bird say and to whom. The tiny microphones used in SOCIAL MATCH are telemetric devices meaning that they transmit radio signals. This allow to have extremely lightweight devices (0.6 grams including harness and battery) but they cannot store the signal, meaning that an antenna and a receiving system is necessary to record. We developed, for the first time, a lightweight receiving system powered by solar panel able to record in the wild.
Thanks to this system, we recorded several birds and scored their behaviour. We captured and equipped groups of four birds (2 breeders and 2 helpers) while they were cooperating to raise the offspring. We quantified their vocal and reproductive behaviour for about a week gathering extremely original and precious data, nothing similar was collected before. Currently the analysis of the vocalizations is still ongoing.
One of the strengths of SOCIAL MATCH is that it was fully integrated in the sociable weaver project (
https://sociableweaverproject.com/(si apre in una nuova finestra)). The sociable weaver project is a long-term project in which for several years birds and their reproductive efforts have been carefully monitored. Working within such a project allowed us to a have a lot of background information for each individual. This information will be essential to interpret the vocal behaviour recorded.
Moreover, such rich dataset provided to be a safety net when unforeseen circumstances delayed the project. Unfortunately, while I was working in the field in South Africa, a gigantic wild fire swept the field site and burned several of the monitored colonies. I lost a field season, but, thanks to already collected data, I could answer a related question to the one planned in SOCIAL MATCH. Instead of acoustic signalling, we evaluated whether the cooperation act (feeding the offspring) is used as signalling itself for potential mates. During breeding, we simulated the presence of potential mates with a playback experiment and we monitored the cooperative behaviour (feeding the offspring). If the cooperative behaviour is used as a signal, we expected the co-operators to increase their feeding rate when a potential mate was present. We found no association between the playback of an unknown individual and the rate at which birds were feeding. This means that we do not have proofs that feeding rate itself is used as a signal. However, it would still be important to monitor vocalizations during reproduction and cooperation and to develop better experimental designs to successfully answer this question. A scientific article about this data analysis is currently in the last stages of revision among co-authors and will be soon submitted to a journal.
