This study in ergonomics was carried out in two French experimental orchards that were completely redesigned to maximize functional biodiversity through the mixing of crops and companion plants, horizontally and vertically, in and between the rows. One site even organized the orchard in a circular design. The hypothesis was that such crop diversity and spatial arrangement influence the way we observe and therefore manage the orchards. In fact, experimental pesticide-free or very low-input multi-species orchards are complex and dynamic systems where uncertainty prevails since all agronomic situations cannot be anticipated. Our study combined interviews, in situ observations and seminars with all the workers involved in the management of both orchards to analyze how multi-species orchards changed their activities, with a focus on the activity of observation: i) How do they operate in the orchard? ii) How, on what and when do they realize observations? iii) What information do they collect and exchange? Beside field observations dedicated to the execution of a task or prescribed experimental observation, observation as a ‘vigilant eye' was also implicitly carried out during other activities. Such observation is constant and incorporated, to the point that none of the operators mentioned it when describing his/her work. We qualify it as an activity of ‘connection' that is part of a unique and sensitive relationship with the orchard offering an overall view "Everything telescopes, your eye, it considers everything at the same time". Such a ‘vigilant eye' allows the operators to understand the complexity of their system and above all to detect and deal with unexpected situations. Moreover, our study emphasized that such observation activity could be better considered, used and shared, from non-focused to legitimate observation to build spatial and technical benchmarks, to make decisions in orchard management, and to improve the overall performance of diversified orchards.