3. PROTOCOLS

The recommended methods and sampling designs for inventory of colonial-nesting freshwater birds in British Columbia are summarized in Table 2. A protocol for each of the recommended methods is provided in this section.

Table 2. Summary of recommended methods for inventory of colonial-nesting freshwater birds in British Columbia at three levels of intensity.

	Recommended Method(s) Note: where more than 1 method is given, methods are listed in order of economy and logistical ease.
Species	Presence / Not Detected	Relative Abundance	Absolute Abundance
Red-necked Grebe	Breeding - Aerial surveys or ground-based surveys	Breeding - Ground-based surveys Wintering - Ground-based surveys or boat transects	Breeding - Direct counts of nests combined with ground-based surveys in adjacent marsh Wintering - Ground-based surveys or boat transects
Eared Grebe	Breeding - Aerial surveys or ground-based surveys	Breeding/wintering - Ground-based surveys	Breeding - Direct counts of nests combined with ground-based surveys in adjacent marsh Wintering - Ground-based surveys or boat transects
Western Grebe	Breeding/wintering-Aerial surveys or ground-based surveys	Breeding - Ground-based surveys Wintering - Ground-based surveys or boat transects or aerial surveys	Breeding - Direct counts of nests combined with ground-based surveys in adjacent marsh. Wintering - Ground-based surveys or boat transects or aerial surveys
American White Pelican	Breeding: Aerial surveys for lakes in Chilcotin	N/A	Breeding - Boat transects on Stum Lake and aerial surveys for foraging on adjacent lakes
Great Blue Heron	Non-breeding -Aerial surveys in open areas or ground-based surveys	Breeding/non-breeding - Ground-based surveys or aerial surveys	Breeding - Direct counts of nests Intertidal foraging -Ground-based surveys Open areas - Aerial surveys

3.1 Sampling Standards

The following standards are recommended to ensure comparison of data between surveys, and to mitigate several sources of common bias. Individual protocols include standards which are applicable to a specific method.

3.1.1 Habitat data standards

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, the terrestrial Ecosystem Field Form developed jointly by MOF and MELP (1995) will be used. However, under certain circumstances, this may be inappropriate and other RIC-approved standards for ecosystem description may be used. For a generic but useful description of approaches to habitat data collection in association with wildlife inventory, consult the introductory manual, Species Inventory Fundamentals (No.1).

3.1.2 Common errors and biases

The goal of most survey designs is to obtain precise and accurate estimates of numbers. An estimate that is free of random errors is said to be precise. This can be improved by increasing sample size, standardizing methods and having censusers of similar experience and training. An estimate that is free of systemic errors is said to be accurate. Unlike random errors, systemic errors tend to bias results in one direction, (i.e., either under-estimate or over-estimate). These errors are usually intrinsic to the method and are not reduced by increasing sample size. It is important to be aware of the source of errors and biases in any method so that they can be addressed and kept to a minimum.

Effort and speed

Errors in an estimate are generally inversely related to effort and directly related to speed for any given method. It is important that these factors are standardized between observers and between sites and years to be able to produce comparable results. For this reason, be sure to record ground speed as well as the time started and finished for each survey (as indicated on the RIC dataforms).

Time of day

Variation in activity levels and behaviour throughout the day often causes change in the detectability of bird species, which may result in a time-of-day effect that biases the results of counts (Shields 1977; Rollfinke and Yahner 1990). For this reason, it is important to relate sampling to time of day as indicated on the RIC dataforms.

Weather

During wet, cold or windy weather, birds may be less active and less detectable. Observers also have trouble concentrating because of the uncomfortable conditions and are more prone to make errors.

Bird density

Accurate counts of birds may be possible when the numbers of birds are not large. However, when numbers increase, estimation techniques have to be used and these have much larger errors than direct counts.

Observability/visibility bias

Not all birds have the same observability. Factors that contribute to variability include:

• size of the bird (small grebes);
• behaviour (e.g., tendency to dive (grebes) or fly away (B-AWPE and B-GBHE) from observer, whether or not the species flocks, tendency to hide in vegetation);
• colouration of bird - many species blend well into their surroundings, making them difficult to detect; and
• atmospheric and light conditions affect the ability of the observer to detect birds: factors such as heat haze, glare, precipitation, cloud cover, wind direction and wind speed can all contribute to bias.