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

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.

Lophozonia tree cavities used for nesting by Slender-billed Parakeets(Enicognathus leptorhynchus)in the central valley of southern Chile:a potentially vanishing keystone resource

Background: The Slender-billed Parakeet(Enicognathus leptorhynchus) is a psittacine endemic to southern Chile and an obligate secondary cavity-nester. In the central valley of southern Chile, most(94%) of the known Slender-billed Parakeet nests have occurred in large, mature southern beech(Lophozonia obliqua) trees(locally known as "pellines"). As relicts of the original old-growth forests of southern Chile, most pellines have been lost due to extensive landclearing throughout the region, potentially threatening long-term persistence of the Slender-billed Parakeet.Methods: We conducted our study in the central valley of southern Chile, near the city of Osorno during three consecutive nesting seasons(November–January, 2008–2011). Nest trees used by Slender-billed Parakeets were located by direct observation of parakeet activities and through interviews with local residents, some of whom were former parrot nest poachers. Nest cavities were accessed, inspected and measured using single-rope climbing techniques. We report means, standard errors, 95% confidence intervals and ranges for 11 cavity-related variables. We also report clutch sizes encountered in active nests, and age estimates of nest trees based on known growth rates of Lophozonia trees in southern Chile. Linear regressions were used to evaluate potential relationships between cavity-related variables and clutch size.Results: We located and measured 38 Lophozonia tree cavities used for nesting by Slender-billed Parakeets. Compared to those used by other psittacines, nest trees were relatively large, averaging 30.4 breast height of 134.5 ter ± 1.1 m in height with a mean diameter at ± 4.7 cm. Based on estimated annual diameincrement, ages of nest trees ranged from approximately 209–485 years. Nest cavities entrances averaged 12.5 ± 0.9 m in height above ground level. Cavity entrance widths averaged 51.0 ± 13.3 cm(vertical) by 11.5 ± 0.7 cm(horizontal). Cavity entrance orientations were apparently random, with no directional preferences detected. Nest cavities were also relatively large, with a mean internal diameter of 39.6 psittacines of this size(ca. 280± 2.4 cm and mean depth of 90.3 –300 g) and broods of up to seven± 24.2 cm. Clutch sizes(2–9) were unusually large for well-developed nestlings were observed.Conclusions: We found that the deep and spacious cavities provided by pellines facilitate successful rearing of large broods, thereby maximizing productivity and fitness. The existence of pellines has apparently allowed Slender-billed Parakeets to adapt successfully to a wholesale loss of ancestral habitat to anthropogenic modifications. Immediate and strategic conservation measures, such as protection of existing pellines and the regeneration and recruitment of additional ones, are recommended for ensuring the survival of Slender-billed Parakeet populations throughout the central valley of southern Chile.