Southern Ontario Waterfowl Plot Survey

Project name: The State of Canada's Birds

Goals : Produce estimates of breeding abundance for the following primary species, American Black Duck, Mallard, Wood Duck, Hooded Merganser, and temperate breeding Canada Goose as well as the following secondary waterfowl species, Blue-winged Teal, American Green-winged Teal, Ring-necked Duck, and Common Goldeneye. Collect breeding data/evidence for select waterbirds (e.g., Common Loon, Great Blue Heron, Belted Kingfisher, Double-Crested Cormorant, American Bittern, Sandhill Crane), shorebirds (e.g., Spotted Sandpiper, Greater Yellowlegs, Solitary Sandpiper, Wilson Snipe), and raptors (e.g., Broad-winged Hawk, Osprey, Northern Harrier). Produce georeferenced observational data that can be related to habitat data.

Dataset summary : The SOWPS provides data to monitor the status and trends of early-nesting duck populations and their habitat. Data from this survey have also been important in monitoring the population of temperate breeding Canada Geese in southern Ontario. Data were recorded to the plot level until 2022; after then, data were recorded to the wetland level. Annual data are summarized in a MS Excel spreadsheet and imported into a master MS Access database.

Year started : 1971

Years (comments) : Ongoing

Season(s) and frequency : Breeding season for waterfowl. Periodically until 2005, then it became an annual survey except during Covid-19 when there was no survey.

Geographic area covered : The survey covers that part of Ontario that is south of a west-east line from approximately the mouth of the French River at Georgian Bay to Mattawa. The survey area includes all of Bird Conservation Region (BCR) 13, except for some islands and the southern parts of BCR 12.

Primary species covered : Waterfowl

Sampling Design : The survey consists of 349 square plots each 0.64 km2 in area. Plots were assigned to either a ‘high’ or ‘low’ strata on the landscape based on Mallard harvest densities from the Species Composition Survey of the National Harvest Survey from 1967-1969 data. The ‘high’ stratum consists of approximately four times as many plots compared to the ‘low’ stratum. Areas of each stratum are 64,407.8 km2 for ‘high’, and 68,313.5 km2 for ‘low’ strata. For plot allocation, uniform grids were prepared for both strata and plots were selected such that the edge of each plot bordered a road for access. The survey was initially carried out every 2-5 years, but in 2005 it became an annual survey. To balance effort across years, plots were randomly assigned to one of four panels (A-B-C-D) to allow for temporal replication and the number of plots per panel was balanced. Since then, two panels are surveyed annually on a rotational basis such that each plot is surveyed twice within a four year period.

Field methods : All suitable habitat for breeding waterfowl within each plot is systematically surveyed on foot, by canoe/boat, or by helicopter by two people. Helicopter plots only occur in BCR 12 due to the remoteness of some plots. Species count data are georeferenced to the scale of the wetland or waterbody. Habitat data are also collected – e.g., wetland type, change over time, anthropogenic disturbance, etc. See Standard Operating Procedures (2014).

Analysis methods : After the data are error checked, annual count data are imported into a master MS Access regional database. Queries are then conducted to update the data for analyses (e.g, update time series, remove flocked birds, etc.). Bayesian models are run to produce breeding population estimates by species and year.

Data format : Annual data are summarized in a MS Excel spreadsheet and imported into a master MS Access database.

Data validation : Previous to 2022, observations (species count data) were collected on data sheets by marking the observation to a wetland or waterbody. In 2022, field tablets (connected to a GPS) with data forms and assigned drop down menus were used to collect data thereby eliminating many data entry errors. QA/QC is completed in MS Excel and queries in MS Access.

Data caveats : There may be concerns from some private landowners over data use depending on the purpose of the study. Landowner permission to collect waterfowl survey data is obtained for plots located on private property.