“The French have conquered the Arabs and won their colony, only in their turn to be conquered by the sparrows,” wrote one visitor to Algeria in 1879. In the nineteenth century, French colonists in Algeria bitterly complained about the apparently substantial theft of agricultural bounty carried out by their enterprising foe. They pushed the government to except sparrows from the 1844 law on hunting that protected most bird species. To this day, the Algerian government carries out dénichage (de-nesting) campaigns against the agricultural pest. This paper explores this conflict between French agriculturists and sparrows in North Africa. It also argues that the contemporaneous introduction of the Australian eucalyptus tree to the region significantly heightened this conflict. Obscured among the many impacts of the intended transfer of Australian eucalyptus and Eurasian sparrows to new continents in the 19th century was the creation of a novel symbiotic relationship between the eucalyptus and the sparrow. Many French settlers became enamored with the sweet-smelling and fast-growing eucalyptus trees in the late 19th century, as they were convinced that it could revitalize deforested terrain and neutralize malarial miasmas with its “balsamic odor.” However, this paper argues based on contemporary sources and recent developments in avian science, the distinctive scent and swift growth of the eucalyptus also attracted many new sparrows to the rising groves of eucalyptus on the plains of the Maghrib. A new tripodal relationship, driven by conflict and cooperation, formed in the 19th-century Maghrib (and Australia) between humans, the genus Eucalyptus, and the genus Passer. This paper uses this complex interaction, in which no single participant has been truly supreme, to reflect on the contributions that evolutionary history and animal studies can make to a deeper understanding of the French colonial period in the Maghrib and the environmental history of the Middle East and North Africa.