Grant: Discovery Grants Program - Individual

Human land use has the potential to impact the structure of habitats. Following logging, regeneration of forests occurs either through natural re-growth or intentional planting, yet these young forests often lack many of the resources found in mature forests. Such alteration of the landscape may provide relatively poor habitat to birds and other species that settle here. Further, regenerating forests often differ considerably in tree species from those originally logged. These 'mosaics' of habitat types often abut one another, creating abrupt zones of contact between species that typically occupy different forests. This can lead to cross-species matings (hybridization) between normally habitat-isolated species. Despite this potential impact, we often overlook how human land use affects the quality of the habitat and the induced interactions this can create among generalist bird species. Our research has focused on two such species, black-capped and mountain chickadees. We study adjacent populations of chickadees: one group occupying a young forest (20-30 years old) and another occupying a 100 year old mature mixed forest (preferred habitat). Our results show that birds breeding in the young forest suffer significant costs - they are less likely to successfully breed and are less able to perform energetically demanding displays. Our proposed research will expand on this work by determining how habitat can alter the way these birds are able to communication with one another, as well as the role that climatic variation - such as the increased variability in temperature commonly associated with global warming patterns - can amplify these impacts. In addition, we will investigate contact between two species that typically occupy divergent forest types - black-capped and mountain chickadees - which now have overlapping populations in parts of northern BC, perhaps due to past logging practices. Our work will determine whether mechanisms that normally prevent interbreeding among these two species are strengthened or compromised in these secondary zones of contact.