Behaviour 2019
Hatching and brood parasitism associated with climate in Chalk-browed Mockingbird (Mimus saturninus)
Rosario M. Jacoby1, Ignacio Crudele1, Paola Salio2, Juan C. Reboreda1, Vanina D. Fiorini1. 1IEGEBA-CONICET, Universidad de Buenos Aires, CABA, Buenos Aires, Argentina; 2CIMA-CONICET, Universidad de Buenos Aires, CABA, Buenos Aires, Argentina

Weather can affect bird populations and their interspecific relationships in several ways. The Chalk-browed Mockingbird (Mimus saturninus) is a Neotropical bird species that inhabits open woodlands and is frequently parasitized by Shiny Cowbirds (Molothrus bonariensis). We used data from three breeding seasons (2017-19) to study how different meteorological variables affect hatching probability of mockingbird eggs and probability of parasitism by Shiny Cowbirds. We used maximum temperature (Tmax) and sum (SumPP) and mean (XPP) precipitations during the eggs stage. The probability of hatching increased in 75% with an increment of 1 C in Tmax and in 12% with an increment of 1 mm in SumPP. Besides, the probability of parasitism increased 14% when Tmax increased 1 C while intensity of parasitism increased 16% for an increment of 1 mm in XPP. Our results indicate that weather affects the mockingbird breeding success directly through the hatching probability and indirectly by affecting the frequency and intensity of brood parasitism. This type of integrated studies helps to better understand the complex relationships between weather and reproductive success of birds.