Non-random spatial distribution of the neotropical cormorant (phalacrocorax brasilianus) in an urban area in Peru

Abstract

**Abstract:** Neotropical cormorants (Phalacrocorax brasilianus) are common seabirds along the Peruvian coast. They frequently perch in urban areas (trees, harbors, poles, etc.), causing potential aesthetic and public health problems due to the dropping of feces on infraestructure and people. Large number of these birds use lighting poles to rest on a narrow median in a 12.5 km coastal highway in Lima, Peru. We hipothesized that the distribution of the cormorants in this highway is not random, but it may be associated with abiotic features of the coastline that may favor prey accesibility. Biweekly counts of cormorants per lighting pole between July 2018 and July 2019 revealed that during the study period the total number varied between 15 to 430 birds, and that only 16% of the total number of posts (N = 651) were occupied. A large amount of cormorants were present in the posts at 1000 h and 1400 h, matching the prefered timing of foraging between mid-morning and mid-afternoon. Cormorants were clustered in four recurrent main groups along the highway, i.e., the spatial distribution was no-random. An AIC model selection approach determined that the presence of the cormorants in these sites were strongly related to a closer distance to the coastline and the isobath 7 m, and to the presence of breakwaters. No relation was found with the turbidity of the sea (measured < 1,300 m from the shorline). These findings suggest that neotropical cormorants may select these sites for a better sighting or detection of prey. Any management for relocation of cormorants from the lighting poles in this highway must take into consideration mainly the distance of perching sites to the shoreline and the occurrence of breakwaters. **Authors:** Sebastián Lozano¹, Carlos Zavalaga¹ ¹Universidad Científica del Sur