“The role of song in the life history strategies of the New Zealand Bellbird”
Wed 11 Aug 2010: 3.00 pm – 4.00 pm
NUS DBS Conference Room 2 [map]
Block S2, Level 3 Mezzanine
(walk up the stairs towards the ridge after the aquarium)
Department of Biological Sciences
National University of Singapore
Host: Navjot Sodhi
About the Speaker – Dr. Brunton currently oversees a thriving Postgraduate research group at the Albany Campus of Massey University, where she supervises more than 25 projects primarily focused on the ecology and evolutionary biology of New Zealand native species. Her research interests include the evolution of song in endemic songbirds (a completed Marsden project), sexual selection in NZ bellbirds, and modeling foraging ecology using stable isotopes.
She has a number of collaborations with researchers at the New Zealand Centre for Conservation Medicine (Auckland Zoo), Department of Conservation, Landcare, Berkeley, University of Colorado and Cornell University. These involve exploring the links between behaviour and conservation biology and the role of diseases and parasites in the evolution and ecology of NZ¹s fauna. These collaborations have lead to numerous postgraduate research projects and exciting interactions with researchers in a variety of fields related to conservation, behaviour and ecology.
About the talk – The bellbird (Anthornis melanura) is a honeyeater endemic to New Zealand, which uses song to defend breeding territories and/or food resources year round. Compared to almost all studied passerines, female bellbirds exhibit significant singing behaviour and sing a variety of complex songs. This intriguing behaviour warranted further investigation and I tested the “dear enemy” hypothesis for female bellbirds.
This hypothesis proposes that the level of territorial aggression toward conspecific neighbours is lower than that shown toward strangers primarily because of differences in ‘threat’. I experimentally tested the dear enemy hypothesis for territorial females using female neighbourstranger playback. I found clear evidence that individual females discriminate between conspecific female neighbour and stranger song. Aggressive responses were strongest during the courtship and chick-rearing stages and involved rapid counter-singing responses and movement toward the speaker.
Most importantly, females were more aggressive toward the songs of neighbouring females. This result is opposite to the dear enemy phenomenon and suggests that neighbouring females pose a greater threat than strangers. We predict that these higher levels of aggression may play a role in sexual selection and polygny prevention and that neighbouring females are the greatest threat to the loss of a mate. It appears the more we learn about bellbirds the more intriguing they become.