DOI: 10.5061/dryad.np5hqbztm
title: Pied tamarins go multimodal in response to anthropogenic noise

description: Sounds produced by human activities are often loud and may mask acoustic
 signals used by other species for communication. To circumvent this,
 animals may use various strategies, including shifting modality completely
 or complementing acoustic information by also using another modality of
 communication. Here we tested the overlooked multimodal shift hypothesis
 using pied tamarins (Saguinus bicolor) as models. We predicted that in
 noisier areas the species would exhibit more scent marking behaviour
 (i.e., olfactory communication), while reducing the emission of long calls
 (i.e., acoustic communication). We collected information on vocal and
 scent marking behaviour in nine groups of wild pied tamarins in Manaus,
 Brazil. We found that scent marking occurrence increased with noise
 amplitude, though the number of long calls did not change. Thus, our
 results do not suggest a shift between channels but complementation of
 information, where scent marking may counteract against the compromising
 of the acoustic channel by the urban environment. This is an interesting
 result from a conservation perspective and supports ongoing efforts to
 create ecological corridors in Manaus, Brazil; once habitat connection is
 established, pied tamarins may be capable of coping with city noise to
 communicate with conspecifics, a key tenet of species survival.
description: The study was conducted in the Central Brazilian
 Amazon, in the city of Manaus, Amazonas state, Brazil. We followed nine
 groups of pied tamarins in different forest fragments within the city
 limits of Manaus. The study area comprised five forest fragments ranging
 from 24 to ~700 ha, where other primate species also occur, including
 <i>Saimiri sciureus </i>and <i>Pithecia
 crysocephala</i>. The most common source of anthropogenic noise in
 all areas is road traffic, though there is also air traffic, park
 visitors, talking and screaming from children and university students, and
 singing and gunshots from military activities. The studied tamarin groups
 varied from 3 to 13 individuals; two of these groups were relatively
 well-habituated to human presence due to frequent public visitation to the
 parks in which they occurred. We followed non-habituated groups by
 radio-tracking. We captured the groups using baited Tomahawk TH105 (10 x
 10 x 40 cm) live traps to attach the radio collars onto the animals,
 placing the traps ~1.60 m above the ground. Once we captured the animals
 we sedated them with 0.2 mg/kg Ketamine<sup>®</sup>
 anesthesia and attached a SOM 2380 transmitter (164.00-164.99 MHz)
 (Wildlife Materials) to the alpha female of each group. The frequencies
 emitted by the transmitter were detected with a two or three-element
 directional antenna and an ATS<sup>®</sup> receiver (164-168
 MHz).  Data collection took place from November 2018 to
 December 2019. We followed each tamarin group for ten complete days from
 6:00 a.m. to 5:00 p.m. In the field, we collected data during five-minute
 behavioral bouts (followed by five-minute intervals), recording all
 occurrences of scent marking and counting the number of long calls emitted
 from all individuals in the group in each behavioral bout. During these 5
 minutes, we also took a 1-minute sample of noise amplitude and calculated
 the equivalent continuous sound levels (LCeq; time-averaged level of
 sound) (dbC), using a calibrated CEL-246 sound level meter (Casela
 Solutions). Calling and scent marking activity were recorded from all nine
 groups, but we only detected scent-marking behaviour in five
 groups.
description: There are missing data related to the coordinate of the place
 where tamarins scent marked or called when GPS error was greater to 15 m
 os mistakenly non-taken. There are also some missing values of amplitude
 estimates that were due to equipment space limit achievement during field
 activity or values of amplitude that were extravagant and related to some
 human-induced activity.