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I used the point count method to assess the abundance of waterfowl (dabbling ducks) within selected drainage channels within Colony Farm Regional Park. Eight point count locations were chosen along the existing dike network in the park based on channel visibility and varying cover of emergent vegetation (yellow pond lily, Nuphar sp.). Each point count was considered one replicate (sample unit). Selected locations (8) were visited on 6 separate occasions (sampling events), with 48 total replicates sampled. Percent cover of yellow pond-lily was visually estimated within each channel section, to a maximum distance of 80 metres. Channel sections were strategically selected on the basis that they varied in percent cover of yellow pond-lily (from 0% to approximately 75% cover) to provide a representative sample. Drainage channels chosen were fairly uniform in terms of their topography, hydrology, surrounding vegetation, and overall width.
I spent five minutes at each point count location observing dabbling duck species, specifically mallard (Anas platyrhynchos) and wood duck (Aix sponsa), within the selected channel sections. Total number, species, and approximate life stage of observed waterfowl within the channels were recorded. Other information I recorded included the start and end time of each point count, weather conditions, date, start and end time of each sampling event, and other notes including the presence of other wildlife and/or predators in the area. All point counts were collected between the hours of 1800 – 2000 hours (prior to sunset at 2030 hours), as this was the time of day that waterfowl within the park were observed to be the most active. Randomization was incorporated into the study by using a random number generator (between numbers 1 to 8) to decide the order in which point count locations were visited during each sampling event.
One problem that I encountered while carrying out my sampling design was the low number of dabbling ducks observed within the channels for the duration of the data collection. To combat this, I visited the site more frequently (i.e. sampled more replicates) to ensure that I would have adequate data to analyze later on. If I were to collect data in the future, I may choose to do so in the fall months when waterfowl occur in greater numbers. A second issue that arose had to do with the site conditions. Connectivity between channel sections led me to realize that not all replicates would be independent of one another. After reviewing relevant literature related to point count methodology, point count locations are suggested to be located greater than or equal to 250 metres apart. Based on the limitations of the study area, and in order to reduce variables between selected drainage channel sections, spacing of the point count locations at this minimum distance was simply not possible. Despite this, the layout of the study area allowed for ample visibility, which prevented double counting of birds and reduced bias among point count locations.
Initial summation of the total number of waterfowl within each channel has lead me to believe that my hypothesis may be rejected. The numbers did not indicate a strong preference of heavily vegetated channels by waterfowl, versus those channels with sparse emergent vegetation cover. This will be subject to further analysis.
