Abundance of White-fronted Parrots and diet of an urban parrot assemblage (Aves: Psittaciformes) in a green Neotropical city

Abstract

Urban ecosystems are evolutionarily recent novel environments acting as biodiversity filters. Psittacidae birds are considered successful urban adapters mainly due to their generalist feeding and opportunistic behavior, allowing them to occupy environments from cold temperate to dry xeric areas. Therefore, it is important to understand how these species interact in the urban environment. We studied the interannual (2013–2016) abundance of the White-fronted Parrot (Amazona albifrons) in the Neotropical cities of Xalapa and Coatepec, in Central Veracruz, México. Additionally, we studied the feeding ecology during 13 months of 6 parrot species detected in the city of Xalapa. The abundance of the White-fronted Parrot was significantly higher in Xalapa than in Coatepec, and it was homogeneous across years. Non-native plants represented 30–41% of Psittacidae diets in Xalapa, where seeds were the most commonly consumed resource. We recorded the highest Psittacidae species richness and highest diet overlap among species by the end of the dry season (April–May). The White-fronted Parrot had the highest plant richness in its diet, followed by the Monk Parakeet (Myiopsitta monachus) and the Green Parakeet (Psittacara holochlorus); yet, the White-fronted Parrot had a specialized diet dominated by two plant species (Grevillea robusta and Ficus aurea). The diet overlap among the three above-mentioned parrot species was not significantly different to a null model, where the White-fronted Parrot and the Monk Parakeet overlapped during the months of February, April, June, and September. The White-fronted Parrot is an urban adapter that has successfully expanded its geographic range via natural means and by human activities. The invasive Monk Parakeet is currently restricted to one park in Xalapa, and it has remained in that stage for many years (i.e., pre-expansion phase). Exotic plant species in Xalapa represent ∼55% of the woody vegetation, some of which have longer flowering and fruiting periods that may have aided the successful establishment of parrot species in urban environments.