Urbanization generates functional homogenization of bird communities. However, the effects of urbanization on the regulation of defoliating insects by insectivorous birds remain poorly understood. It is possible that the dietary specialization of species and communities along urbanization gradients explains the lack of clear patterns in the intensity of predation exerted by birds in environments affected by anthropogenic disturbances.

Thus, it remains to be precisely identified which species, among those present in insectivorous bird communities along urbanization gradients, play an active role in the biocontrol of pest herbivores. Moreover, some studies have also shown that dietary specializations can occur at the intraspecific level in response to variations in resource availability in the studied environments.

The URBIRDS project aims to empirically determine which species actively contribute to the predation of defoliating herbivorous insect larvae and to analyze how their degree of dietary specialization varies depending on the intensity of urbanization and the availability of food resources.

To achieve this, we will use a combined approach involving acoustic ecology to characterize insectivorous bird communities and "cafeteria" experiments, where high-performance cameras will be used to identify the feeding species and document the selected arthropod prey.

The specific objectives of the project are as follows:

1. Identify the bird species involved in the biocontrol of lepidopteran larvae along the urban gradient.

2. Study variations in the composition of arthropod communities (herbivores and predators) along the urban gradient.

3. Assess the degree of intra- and interspecific specialization within insectivorous bird communities.

4. Analyze the impact of dietary specialization on intra-guild predation.