Date of Award


Publication Type

Master Thesis

Degree Name



Biological Sciences


Bioacoustics, Birds, Female song, Fragmentation, Restoration, Tropical dry forests


Dan Mennill




Vocalizations provide important information about how animals respond to changes in their environments. In this thesis, I use bioacoustic tools to investigate how birds respond to habitat restoration and fragmentation in tropical dry forests of Costa Rica. Tropical dry forests are one of the most imperilled ecosystems in the world, and my study site, the Área de Conservación Guanacaste, is home to the largest remaining stand of this unique ecosystem. In both chapters of this thesis, I collected recordings of bird vocalizations to study avian responses to changes in the Área de Conservación Guanacaste. In my first data chapter, I used passive acoustic monitoring and point-count surveys to measure bird community responses to tropical dry forest regeneration. I found that bird diversity and abundance increase as regenerating forests increase in age. I also found that bird communities become more similar to primary forests with increasing forest succession. My research provides evidence that restoration efforts in northwestern Costa Rica are encouraging the recovery of bird communities. In my second data chapter, I used bioacoustic monitoring to study female and male vocal behaviours in Rufous-and-white Wrens living in fragmented mature forests, with a focus on the influence of neighbours, time of day, and time of year. I found that female wrens changed song types more often with more neighbours, however, I did not observe any effect of neighbours on vocal behaviours in male wrens or on duetting behaviours in both sexes. I found changes in vocal behaviour of female and male wrens in response to time of day and time of year corroborating previous findings. My research contributes to two areas of bird conservation research that require more attention: long-term monitoring of bird communities in changing landscapes, and behavioural monitoring of birds for conservation purposes. Understanding how birds respond to changes in their environment can help guide conservation practices to ensure the continued persistence of healthy bird communities and populations.