October 27, 2023 11:00 am
Fall – Sunny with few clouds and low wind
Due to access issues, I’ve switched to a new study area: Mystic Vale in Victoria, BC. The forested area is a mix of deciduous and coniferous woodlands and brushes where many songbirds such as the Chestnut-backed Chickadee (Poecile rufescens), Golden-crowned Kinglet (Regulus satrapa), Spotted Towhee (Pipilo maculatus), Song Sparrow (Melospiza melodia), Dark-eyed Junco (Junco hyemalis), and American Robin (Turdus migratorius) sing. Since the park is sandwiched between busy roads, sounds of traffic can be audible to varying degrees throughout the forest. I noticed fewer instances of birdsong at locations closer to a road, while I heard more frequent birdsong and a greater variety of birdcalls further from a road.
The decreased species diversity of songbird vocalization could be due to an overall decrease in species abundance, as songbirds may choose to forage and nest in quieter areas to avoid being disturbed by the loud noises of the road. However, certain songbird species could also be more resilient than others to anthropogenic sound pollution.
I hypothesize that the species diversity of songbird vocalization activity is determined by the distance from a road. My prediction is that songbird vocalization diversity is proportional to the distance from a road, meaning that the greater the distance from the roads, the greater the diversity of songbird vocalization.
H1: Songbird vocalization diversity increases with increasing distance from a road.
H0: Songbird vocalization diversity does not increase with increasing distance from a road.
My response variable is the abundance of each songbird species heard calling at a given point count station. As I am identifying species and then counting individuals, this variable is categorical. I may use the Shannon Diversity Index to interpret and compare my categorical species diversity data. My explanatory variable is continuous: the distance (in m) of the point count station from a road.
I plan to record and identify birdsong at point count stations on a distance gradient (e.g., 0 m, 50 m, 100 m, and 200 m from a road). In addition, I will use the Merlin Bird ID app to assist in species identification and to make a complete species list.