To See, Hear and Speak: How Counts of Birds in Individual Trees Help Address the Environmental Causes of the Sahel

Abstract

the three ‘wise monkeys’ originating in Japanese and Chinese philosophical traditions going back at least 1000 years. Mizaru was the monkey that covered its eyes, Kikazaru plugged both ears with fingers, and Iwazaru held its mouth shut with a clasping hand. Together they “saw no evil, heard no evil and spoke no evil”, a wonderful ambiguity, because is it really a virtue to withdraw? Or is it a virtue to see and hear attentively, and thus sense the state of the world around us; and then speak about it? This special issue of ARDEA is filled with papers painstakingly reporting the work of a small and dedicated team who set out to map the birds across the entire Sahel (an area the size of the USA!). Although mapping is inherently biased by the knowledge and cognitive facilities, as well as the interests, of the mappers (Malavasi 2020), within the limits of their sensibilities, and negotiating serious political and safety realities, the team tried to do this in temporally and spatially unbiased and methodologically robust and repeatable ways. The way that single trees and bushes disperse across the landscape of the Sahel, rather than connect-up into a dense forest, inspired a mapping approach that is both brilliant and unique. Rather than taking ‘an area’ as the spatial unit to measure bird abundance, the team began with ‘individual trees’ (Figure 1), with the plots in which these trees occurred being carefully pre-selected along trajectories that could be travelled “easily” (i.e. within the reach of a 4×4 vehicle). In their ensemble, the effort would give unbiased measurements of birds ánd trees across the entire Sahel, from Senegal in the west to Ethiopia in the east. This design also enabled assessments of the consequences of the steep latitudinal gradients in rainfall as one moves south from the Sahara sands towards the Sudan forests across 1000 km, and sometimes less. Theunis Piersma & El-Hacen M. El-Hacen