Category: Nancy Elliot

I have made several changes to my data collection strategy since last time. While I am still using a haphazard sampling method with the help of Google maps, and point counts for estimating Black-billed magpie abundance in relation to human presence in Edmonton’s Hermitage park, I have moved to a dependent double-observer approach. Also, I have reduced the time frame spent at each point count to 20 minutes. There was an additional one-minute settling time given at each point, and five minutes were given to walk from one point to another. Additionally, I have chosen to assess human presence solely by recording the number of pedestrians observed during given time frame. Doing so resulted, I believe, in less bias than recording various predefined “human traces”.  Moreover, this time, I chose to record separately: 1. No. of birds seen within the first 5 minutes, 2. No. of birds seen flying over. Doing so will give the reader an idea of whether the presence of observers might have attracted more birds after the first five minutes. Birds seen flying over are generally noted separately in current similar literature, because they cannot be recorded in standard density calculations (Gregory et al. 2004).

To increase the accuracy of my results, I have increased the number of point counts from five to nine which I sampled on two different days (March 24th and March 28th 2018).

As I will explain further in my final report, my literature review as well as previous comments on my past assignments has led me to make those changes. My intention was to minimize bias, standardize my sampling as much as possible, and increase the use of randomization/replication in my sampling strategy. Using a dependent double-observer approach made it much easier to implement my sampling design. Not only did it reduce observer bias, less coordination was needed than it was using different observers for each point count. The only problem encountered was that most of the time, the walking time took a bit less than five minutes, so the real “settling time” was more than a full minute at most points. It was hard to keep track of the exact time spent at each location for that reason.

Gregory, R. D., D. W. Gibbons, and P. F. Donalds. 2004. Bird census and survey techniques. Pages 17–55 in R. E. Green, W. J. Sutherland, and I. Newton. Bird ecology and conservation: a handbook of techniques. Oxford University Press, New York, New York, USA.

I have made several revisions to my sampling in the field. While the overall strategy will stay the same, haphazard with subjective location selection, I will be decreasing the size of my quadrats from 100cm x 100cm to 30cm x 30cm.This reduction will allow for quicker observation of the damaged area and give an overall clearer picture. In addition to the reduction of my quadrats I will now be looking at the damage to the Kentucky Bluegrass species instead of the Ryegrass species. With the turn from winter to spring, Kentucky Bluegrass has shown itself to be the dominant species in the grassy area. Also, I will now be taking 10 replicate samples, 5 grazing and 5 non-grazing, in order to satisfy the rule of ten. In satisfying the rule of ten I hope to achieve a more accurate representation of the ecological processes that are occurring. There were no major difficulties in implementing the original sampling design, but I believe that these changes will allow for a more streamline process. There is one ancillary pattern that may have an effect on the original hypothesis. This pattern is the increasing presence of the number of geese in the grazing areas with increasingly warm weather. It appears that on warm and sunny days the number of geese in the grazing area of the park will increase by anywhere from 2 to 8 geese. While this does not change the fact that the geese are damaging the Kentucky Bluegrass in the area, it is worth observing the damage done on days where geese numbers are higher versus the damage done on days where geese numbers are at 2 or 3.