I plan to study a species of bird that is common in my backyard. The House Sparrow: Passer domestics . This particular species is a permanent resident (non migratory) in North America and is commonly found in urban centres, backyards and parks.
I have chosen the gradient to be along one of my fences that spans the entire length of my yard that houses my in ground perennial garden bed. The three locations along the gradient are:
- Dense shrubbery (raspberry plants)
- A young maple tree (estimate 20ft tall) with lots of branches and with low lying perennial plants below
- A columnar tulip tree (less branches, approx. 40ft tall) surrounded by tall perennial plants and spent sunflower stalks
Hypothesis: Habitat quality influences the presence of the House sparrow
Formal Prediction: The greater density (cover) of the plant material the greater the number of House sparrows
Response variable: The total number of birds landing in each different location (categorical)
Explanatory variable: The density, abundance and types of vegetation used for habitat (continuous) Percent coverage of plant material
I am not clear that vegetation density differs between the sites based on your description, they just sound different. Also, your hypothesis is based on habitat quality and then your prediction is about density. Make sure they are consistent. How does quality vary between your sites? I would say vegetation type differs for sure.
Hello, I am just providing constructive criticism as outlined in blog post 5. Your hypothesis could be more clearly stated by explaining what factors affect habitat quality. But reading your prediction it seems you are focussing on the density of plant material so include that in your hypothesis. The predictor and response variables seem easy to measure so that is good!