The use of active vision can increase the success of already excellent visual predators and improve the performance of predator with limited vision. Moreover, by travelling faster towards their prey, killer flies may avoid losing track of it, a real danger when chasing moving prey with low- resolution eyes potentially avoided thanks to active vision.īy employing active vision, each of the predators considered can achieve impressive performances, despite relying on very different strategies to capture prey. However, killer flies create strong looming stimuli which may trigger their prey to produce evasive manoeuvres, thereby slowing down. This increased speed restricts the flies' ability to steer. Killer flies use a combination of gravity and wing acceleration to increase their speed when chasing prey from above. The final experimental chapter considers killer flies, Coenosia attenuata, which chase moving targets aerially. Assessments of differently sized targets have similarities with the behaviour exhibited by jumping insects, which use motion parallax, a form of active vision, to assess jump distance, suggesting darting robber flies also use motion parallax to predate. Prey is beyond the robber fly's stereopsis range during the period of assessment. After assessment, they attack from a position correlated with the target's absolute size, not its angular size. Prior to attacking, darting robber flies translate their body around a central point, assessing their prey. The second experimental chapter addresses how darting robber flies, Psilonyx annulatus, aerially attack static prey. The timing of head movements greatly increased the chances of strike success, with earlier movements increasing the success rate. By using statistical models, we identified what factors elicited strikes and, importantly, their success rate. Praying mantids are stationary terrestrial predators, which use their extremely mobile necks to visually track prey until it is within reach. The first experimental chapter considers the African praying mantid, Sphodromantis lineola. This thesis examines three predatory insects with different predatory strategies, to understand the extent to which active vision can be used in predation. Insects have immobile eyes but can direct their gaze by moving their heads and bodies. However, an animal's visual abilities are greatly affected by how it moves its eyes, known as active vision. Visual predation requires precise and accurate behaviour, for which many predators have evolved excellent visual skills.

Additionally, nearly one-third of falconiform species, as well as some accipitriformes species, maintain activity during the crepuscular period (Mitkus et al. Overall, as a group, owls actually exhibit a broad range of activity patterns and habitats (Bowmaker and Martin 1978 Braga 2006). 2004 Sarasola and Santillan 2014 Martin 1986).

1999 Martins and Egler 1990 Motta-Junior 2006 Motta-Junior et al. However, the ferruginous pygmy owl Glaucidium brasilianum maintains some activity during the day and the snowy owl Bubo scandiacus hunts during the daytime, the American barn owl Tyto furcate is most active in twilight, the burrowing owl Athene cunicularia is cathemeral, and the stripped owl Asio clamator is crepuscular and nocturnal (del Hoyo et al.

Perhaps a most obvious example is revealed in their activity patterns, where most raptors are considered diurnal, except the owls, which are considered nocturnal, a habit they share with two other avian orders for which we have genome sequences (Caprimulgiformes and Apterygiformes) (Martin 1990 Mikkola 1983 Martin 2017 Zhan et al. Although grouped together as key apex predators, raptors are phylogenetically heterogenous assimilation with many morphological and ecological differences. Birds of prey, also collectively known as raptors, consist of the Falconiformes (falcons and caracaras), Accipitriformes (eagles, buzzards, hawks, kites, and Old World vultures), Cathartiformes (New World vultures), Cariamiformes (seriemas), and Strigiformes (true owls Strigidae, and barn owls Tytonidae) (del Hoyo et al.

Eagle eye color