The social system of the El Oro Parakeet (Pyrrhura orcesi)

The El Oro Parakeet is an endangered, endemic bird species of South-West Ecuador. It is confined to mountain cloud forest in a very narrow altitudinal range from 800 to 1200 m. Due to this geographical restriction and the enormous habitat fragmentation and loss, resulting from logging and cattle ranching, the population size has declined drastically in the last decades. In the year 2008 the IUCN listed the El Oro Parakeet as endangered, since the population size was estimated to be less than 1000 individuals and declining.

Pyrrhura orcesi is a cavity-nesting species and lives socially in groups of 3 to 15 individuals.

Within its small range, the most important site for the parakeet is the reserve Buenaventura (79o 46' W 3o 40' S) owned by Fundación Jocotoco. The population in the reserve and the adjacent areas is approx. 180 individuals. It is also the only site where the parakeet is officially protected.

I my diploma thesis I study the social system of Pyrrhura orcesi by analyzing the genetic structure of the flocks (kinship-analyses). One main point is to test the hypothesis that the parakeet shows cooperative breeding. If this is the case, the effective population size will be even lower and the negative effects of fragmentation and habitat loss on the viability of the population will be fortified. This would make further conservation efforts inevitable.

I will further try to find out whether the cooperative breeding is based mainly on direct or indirect fitness benefits.

Finally, I will analyze migration of individuals between the different flocks. In this context, I will test if there are obstacles to migration that lead to subdivision of the population into subpopulations.

Additionally I will assess the frequency of inbreeding and the genetic diversity of the whole population to get further information about the stability of the population.

In the first part of my work, I collected blood samples of birds in the Buenaventura reserve. In the laboratory of PD Dr. Gernot Segelbacher (Forstzoologisches Institut) I will establish a genetic marker system. In my case microsatellites, short tandem repeats of 1-6 base pairs, are the ideal markers. They are neutral and have a high mutation rate thus they reveal recent changes in the population structure and can be used for kinship-analyses.