Breeding success of the burrowing parrot (Cyanoliseus patagonus) in anthropogenic nesting substrates

Abstract

Background The Burrowing Parrot (Cyanoliseus patagonus) nests in sandstone and earthen ravines and cliffs, excavating its own cavities. As in other cavity-nesting birds, reproduction is constrained by the availability of suitable nesting substrates, making the use of anthropogenic substrates particularly relevant. The expansion of urban, peri-urban, and rural landscapes, together with the species’ conservation vulnerability, underscores the need to assess the fitness of individuals breeding in human–modified habitats. Methods In this study we describe for the first time the daily survival rate of nests (DSR) and the breeding success of the species in nests constructed in anthropogenic substrates (quarries and roadsides) in northern Patagonia, Argentina. We monitored 74 nests in six colonies established in urban and rural areas during two breeding seasons, 2021–2022 and 2022–2023. We estimated clutch size, hatching success, daily survival rate of nests (DSR), brood size, productivity and breeding success, and evaluated the potential effects of the urban and rural contexts, as well as the characteristics of ravines and nests, on breeding success. Results DSR and hatching success were similar between seasons, whereas breeding success showed higher, although not statistically significant, values in 2022–2023 (88%) than in the previous season (67%). Nests built in quarries with human activity were more successful than those found on roadsides, as were nests built at higher heights and facing SE. Average clutch size, mean number of chicks per nest and mean number of fledged juveniles per breeding pair were similar to those previously reported for colonies in natural nesting sites. Conclusion Breeding success of the burrowing parrot nesting in anthropogenic substrates provides evidence of the potential of these environments for the conservation of a species, increasingly common in the cities along its distribution area. These environments appear to play a key role in the number of breeding individuals of the species at a local level, and, eventually, in its global population trend.