Dr. Myriam E. Mermoz

Research Fellow CONICET | This email address is being protected from spambots. You need JavaScript enabled to view it.

During my PhD studies (1991-1996) I analyzed the brood parasitism by the Shiny Cowbird (Molothrus bonariensis) and the interaction with a host cited as highly parasitized: Brown-and-yellow Marshbird (Pseudoleistes virescens). The main questions I addressed were confirming these high rates of parasitism, evaluating the costs they imply for the host's reproductive success, and analyzing whether the Brown and Yellow Marshbird has developed any defense mechanisms. Within the topic of brood parasitism, I carried out a Posdoc (1998-2000) in the Instituto de Ecología, A.C. (Xalapa, México). Using the fully resolved phylogeny of Icteridae that included the 5 species of brood-parasitic cowbirds, I analyzed which of the characteristics that had been proposed as adaptations to brood parasitism (e.g. small and thick-shelled eggs, short incubation periods, accelerated growth rates of the chicks) could be considered as true adaptations.

Since 2001, I focused my studies on cooperative breeding. In this system, other individuals besides the parents - helpers – also perform parental care duties. Using Brown-and-yellow Marshbird as model species, between 2001-2010 I followed two “sub-populations” in Gral. Lavalle (Prov. de Buenos Aires). In 2014 I moved my study area to Gral. Madariaga (Prov. de Buenos Aires) whereas I initiated a study on the importance of road borders for the conservation of native bird species in the Flooding Pampas. The result of this study was the PhD Thesis of Daniela Depalma (2020). From 2016-present, I resumed the study of cooperative breeding in that new location. Here we monitor the Brown-and-yellow Marshbird nests to individualize all the fledglings with unique combinations of color bands. By intensively monitoring these individuals throughout the year, we attempt to obtain information on longevity, group dynamics, and reproductive success since they leave the nest. I believe that the holistic approach of a species as a model, addressing its multiple particularities, can be much more enriching to achieve a greater understanding of the study system. Therefore, we will soon address topics related to Brown-and-yellow Marshbirds vocal communication and other aspects of basic biology necessary for a better understanding of the species.