Which mechanism drives long tail evolution in a bird species?

DIEGO T TUERO; JUAN C. REBOREDA; CAROLINA FACHINETTI; ALEX JAHN

Congreso; XVI International Behavioral Ecology Congress; 2016

Fork-tailed Flycatcher (Tyrannus savanna) is a migratory andsocially monogamous bird. This species shows sexual dimorphism in tail length (males:15.7-31cm and females: 9.7-21.7 cm). Under a sexual selection scenario is expected thatmales with longer tails have higher reproductive success. We studied individualbreeding success, frequency of extra-pair paternity and mate choice in Fork-tailedFlycatcher during three breeding seasons (2011-2013). We worked at El Destino Reserve(Argentina). Fledgling number and nest success were not associated with male orfemale tail length. We found a low frequency of extra-pair nestlings (5%-10% in13-23% of the broods) and it was not associated with male tail length. Finally,long-tailed males bred with long-tailed females. Overall, we did not findevidence of an association between tail length and reproductive success in thisspecies.