We have successfully developed a survey technique to monitor the population of cotton-top tamarins (Saguinus oedipus) in Colombia. This allows us to monitor the impact of our conservation actions on the population.
The survey is through the departments of Atlántico, Bolívar, Sucre, Antioquia, Córdoba
From Savage et al., 2016The field team surveyed areas using a “lure strip transect” method [11] from January through June 2012. Monkeys were surveyed in the morning, between 0700–1100, as this is the period of the day they are most active. Two teams walked parallel to each other 200 m apart, with both teams playing recordings of unknown cotton-top tamarins long calls (continuous play of 60 s of calls at 80 dB followed by 30 s of silence) from a high-quality playback device. The broadcast loudspeakers were generally oriented to cover forest ahead of each team as they proceeded along the transect. Previous validation trials of the method, using the long-term field site of Proyecto Tití, showed that: (a) all groups responded from within the strip of 200m width formed by the two teams; (b) it was possible to distinguish between those responding from inside and outside the strip; and (c) groups became rapidly habituated and stopped responding after multiple trials [11]. In the 2012 survey, as in the 2005 survey, the team surveyed each transect once to avoid habituation. When cotton-top tamarins were observed, the field team recorded the compass bearing the group arrived along, the location of the animals along the transect and the number of adults, juveniles, and infants. Vegetation type was classified along the transect every 50 m as (a) primary forest, (b) secondary forest, (c) forest with cleared undergrowth, (d) area of regrowth with young trees producing fruits, (e) area of regrowth without fruiting trees, (f) open pasture or agriculture land, or (g) land converted for human settlements. Based on previous behavioral research [9], we attributed a preference index to each habitat type (a-g) reflecting its use by the tamarins: 0 (non-suitable habitats: e, f, g), 1 (habitats used only for feeding: d) and 2 (preferred habitats: a, b, c).