The table below outlines the type of surveys that are used for inventorying waterfowl for the various survey intensities. These survey methods have been recommended by wildlife biologists and approved by the Resources Inventory Committee.
Table 4. Types of inventory surveys, the data forms needed, and the level of intensity of the survey.
Survey Type |
Forms Needed |
*Intensity |
Transect:
|
|
|
Transect:
|
|
|
Transect:
|
|
|
Helicopter:
|
|
|
Helicopter:
|
|
|
Obs. Station:
|
|
|
Obs. Station:
|
|
|
Obs. Station:
|
|
|
Call Playback |
|
|
Nest Count (any method) |
|
|
Aerial Photography |
|
|
Mark-Recapture / Resight |
|
|
* PN = presence/not detected (possible); RA = relative abundance; AA = absolute abundance
The following standards are recommended to ensure comparison of data between surveys, and to mitigate several sources of bias common in surveys. Individual protocols provide more detailed standards applicable to the method(s) and design recommended.
A minimum amount of habitat data must be collected for each survey type. The type and amount of data collected will depend on the scale of the survey, the nature of the focal species, and the objectives of the inventory. As most, provincially-funded wildlife inventory projects deal with terrestrially-based wildlife, standard attributes from the terrestrial Ecosystem Field Form developed jointly by MOF and MELP (1995) will be used. The manual, Species Inventory Fundamentals (No.1), contains a generic discussion of habitat data collection and will eventually outline a list of specific requirements for surveys for waterfowl and their allies (Appendix E).
Observer - Skills, experience and motivation of observers will influence how many birds they detect. For relative abundance between sites in one year, one observer may be used consistently; otherwise, reduce bias by rotating observers, ensuring each site is surveyed an equal number of times by each observer. Use experienced observers or train observers and test their skills to ensure that a consistent standard is met.
Volunteer Survey Programs - an example. The way to improve the accuracy and precision of data collected by volunteers is to provide training and feedback. For example, the Burrard Inlet Environmental Action Program (BIEAP) in cooperation with the Vancouver Natural History Society (VNHS) and the Port Moody Squadron organizes volunteers to collect bird survey data in Burrard Inlet four times a year. Volunteers attend a bird species identification workshop a few weeks before each survey. Each survey group is led by an expert birder, and the data are recorded by someone who has been trained before the day of the survey. Detailed guidelines are provided to each crew so that birds can be counted within clearly delineated areas. A social event is held to thank volunteers for their time and effort and survey results are sent to each volunteer in a follow-up letter.
Effort - The number of birds detected will increase with sampling effort (i.e., the size of the area sampled and the time spent sampling per unit of area). Effort should be maximized to improve accuracy and standardized so that data from different samples can be compared.
Density - It is difficult to count birds and distinguish between species when they occur at high densities. In contrast it may be difficult to detect birds at low densities. More effort or different survey methods may be needed to sample birds at high and low densities.
Habitat - It is easier to detect birds in some habitats than others. Different amounts of effort or different survey methods may be needed to sample different habitats.
Bird Species/Sex/Age Class - Some species/sex/age classes are easier to detect than others because they are noisier, more conspicuous, breed earlier, or are easier to capture. Some of these factors are discussed in Section 2. Each species/sex/age class may require different survey methods.
Bird Activity - The behaviour of birds (e.g., feeding, sleeping, incubating) will alter their visibility. Count birds at times of the day and/or year when they are engaged in activities that make them most visible.
Time of Year - Visibility of breeding birds decreases over the summer as vegetation grows. More accurate counts will be obtained early in the season.
Time of Day - Activity patterns of birds vary with time of day. Surveys should occur at a standardized time.
Tidal Rhythm - Activity patterns of birds vary with the tidal height. Surveys along coastal shorelines and estuaries should occur at a standardized tidal height.
Weather - Weather can alter bird activity and the visual acuity of observers. Surveys should occur under standardized conditions and never in poor weather.