Conclusion 

Because our project contains a lot of variables and we were not able to control every single one, we are unable to say that noise level directly affects the amount of birds, but we are able to say that noise level is indicative of the amount of birds you are likely to detect in an area. Generally, the greater the noise level, the fewer the birds. 

Greater noise level can indicate higher levels of human activity (which is especially relevant in human structure habitats), which can deter shy birds that don’t like to be where humans are. Greater noise level can also indicate a lower level of trees which would otherwise block noise from passing through, and as trees are the main habitat for a lot of the birds that were found only in locations with noise levels under 55 dB, it makes sense that louder areas with fewer trees would also have fewer of these birds and fewer birds in general. It should be noted, though, that since we were relying on Merlin Bird ID for sound detection of a lot of our birds, we may have reported fewer birds than were actually present in louder areas because the sound ID would not work as well -- this is something to consider in future versions of this project. 

Our main outlier, T060, was a wetland location with a noise level of 65 dB and high number of birds. Most of these birds were Barn Swallows. As we found in our background research, Barn Swallows don’t mind being in human-frequented spaces, so they are exempt from the above logic. Furthermore, the inverse relationship between noise level and number of birds is more applicable to shy, elusive birds (ex. Cedar Waxwing, Red-eyed Vireo) than it is to birds that rely more on humans for food and habitat (ex. House Sparrows, Barn Swallows). 

Hairy Woodpecker     Great Blue Heron

next steps

One new question that had come up during our investigation was what other variables could affect where a bird is typically found. In our investigation we had mostly focused on one variable so researching others could provide more information on a bird's preference in terms of environment. If we had wanted to dive deeper into our research question we could look at specific noises found throughout the city to see how birds react.

For future research we would focus on certain locations to obtain more consistent data to give us a more accurate result. With those new locations it would be interesting to look at other variables that could affect the bird population there. 

If anyone would want to try this project we would recommend sticking to specific locations if possible, as well as maybe only recording birds by sight to avoid differences in Merlin efficiency (which would come from varying noise levels). Along with that, making sure to have all the necessary materials and keep track of data efficiently.