3. PROTOCOLS

3.1 Sampling Standards

The following are guidelines for conducting standardized songbird inventories in the province. Close adherence to these guidelines will permit the collection of reliable data that should satisfy individual and corporate inventory needs, as well as contribute to biodiversity monitoring at local, regional, and provincial scales.

3.1.1 Personnel

Probably the most essential component for the collection of accurate data is a competent observer. This cannot be overemphasized. Proficient bird observers obtain species estimates within 90% and abundance estimates within 80% accuracy (Ralph et al. 1993). Various studies have shown that observer bias is one of the most noteworthy bias factors in trend analysis of songbird populations. In fact, one study suggests that a potential reason for the apparent recent increase in some songbird populations (as determined by breeding bird surveys) is the apparent increase in skill of bird watchers (Sauer et al. 1994). In another study, it was found that a significant change in trend resulted if individual observers first year of observation in a breeding bird survey was removed (Kendall et al. 1996).

As well as being able to visually identify birds, field workers must be proficient at identifying species by their songs and calls. Therefore, recordings of birds in the study area, especially for the less common or unexpected species should be provided for surveyors. Inventory personnel should be tested frequently on their ability to identify bird calls. The quality of the observer will determine the quality of the data.

Time should also be invested in training personnel to estimate the distance from themselves to singing birds within different habitats. This will require training in the field. For inventories which use the variable radius point count method it is recommended that there be a two week training period for novices in distance estimation. This is done by estimating the horizontal distance of a singing bird, and then either pacing the distance or using a rangefinder to derive the actual distance. Note that there is great variability between species in the range travelled by the bird's song. For example a Winter Wren will be heard more loudly and probably over a greater distance than a Brown Creeper.

Good hearing ability is essential because many birds, particularly in forested habitats, are detected by sound only. Differences in hearing ability between observers may strongly affect survey results (Scott and Ramsey 1981). It is important to rotate observers equally between stations so that observer error is equally distributed.

To maintain a high skill level, the project leader should assess all potential workers, and provide guidance where needed. Field training sessions should be held prior to data collection to increase observer expertise and to evaluate and correct for differences between observers (e.g., Kepler and Scott 1981). The performance of observers should be recorded for possible use as a weighing factor or criteria for stratification in the analysis of data. These tests should be done prior to surveys. Data sets can be tested for observer effects through stratification by observers (ANOVA) (Buckland et al. 1993) or addition of covariates or weighing factors for trend models (Sauer et al. 1994, Thomas 1996, Link and Sauer 1997). However, this is not necessarily a good strategy for a reduction in the power of tests and precision of estimates may result with the addition of covariates (to trend analysis) or strata (to ANOVA) designs. Power analysis can be used to explore this problem (see manual No.1, Species Inventory Fundamentals, Appendix G). The best strategy is to train observers adequately to minimize potential bias rather than rely on complex statistical analysis.

3.1.2 Weather

Poor weather such as high winds, rain, and fog can inhibit both bird behaviour and observer ability. Refer to Table 2 for weather standards.

Table 2. Acceptable and unacceptable weather conditions for songbird surveys.

	Acceptable	Unacceptable
Wind	Beaufort 0 (< 2 km/hr). Calm. Beaufort 1 (2-5 km/hr). Light air. Beaufort 2 (6-12 km/hr). Light breeze, leaves rustle.	Beaufort 3 (12-19 km/hr). Gentle breeze, leaves and twigs constantly move. Beaufort 4 (20-29 km/hr). Moderate breeze, small branches move, dust rises. Beaufort 5 (30-39 km/hr). Fresh breeze, small trees sway. Beaufort > 5
Precipitation	None Fog Misty drizzle Drizzle	Light rain Hard rain Snow
Temperature	> 7 0C (breeding) > 3 0C (breeding in central & northern interior of BC) > 0 0C (winter coast) > -10 0C (winter interior)	< 7 0C (breeding) < 3 0C (breeding in central & northern interior of BC) < 0 0C (winter coast ) < -10 0C (winter interior)

3.1.3 Time of Year

Breeding Season

• The majority of bird surveys are conducted during the breeding season, when most species of songbirds are on territory and singing (Ralph and Scott 1981; Verner 1985; Bibby et al. 1992). Ralph et al. (1993) recommend field work for population surveys in temperate North America be conducted from May 1 to June 19. For British Columbia, especially at the northern latitudes (and higher elevations), this period can be extended into the first week of July (i.e., May 1 to July 10). Note that the breeding season may not start until mid- to late May for most species in the north.

Migration

• Surveys of migrating songbirds can provide data on timing of migration, relative abundance, and species composition. Bird identification during fall migration can be difficult for observers. Many of the brightly coloured males of the breeding season have moulted into non-breeding plumage, and juvenile birds have yet to take on their adult plumage. It is difficult to produce estimates of abundance at this time of year unless birds possess individual markings.

Non-breeding Season

• Songbirds are typically less common and non-territorial during the winter season. Although numbers are lower, survey results still have high management value since the birds surveyed are resident, and winter is often a limiting time due to factors such as extreme cold and low food availability (Manuwal and Huff 1987; Huff et al. 1991; Ralph et al. 1993). Point count surveys outlined in this manual are sufficient for determining presence or relative abundance during the non-breeding season.

3.1.4 Time of Day

• All breeding bird surveys should be conducted within the first three to four hours after sunrise. Singing rate is thought to be highest just before official sunrise and then declines slowly for the next four hours. Ralph et al. (1993) believe the best time for surveys is within these four hours because the singing rate is most stable.
• Until evidence shows otherwise, winter bird surveys should begin at official sunrise and continue for four hours. More work needs to be done regarding the best time for winter inventory. Birds in winter do not exhibit a diurnal song pattern as do breeding birds. However, activity is greatest in the first few hours of the morning.

3.1.5 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, 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 as well as a list of the specific requirements for songbird surveys (Appendix E).

Most studies are interested in correlating bird occurrence and abundance with habitat attributes and types. Ralph et al. (1995) summarize these two approaches: A random or systematic sampling of bird communities across the entire landscape will cause some stations to fall on or near the boundaries of habitat types. These data can be used to form post hoc associations with habitat and will reflect the variation in habitat conditions within a landscape and along the continuum of habitat. Under some circumstances, a better design would be to systematically place sampling stations (units) within the interior of habitat types so as to sample only those well defined habitats.

3.1.6 Survey Design Hierarchy

Songbird surveys follow a survey design hierarchy which is structured similarly to all RIC standards for species inventory. Figure 1 clarifies certain terminology used within this manual (also found in the glossary), and illustrates the appropriate conceptual framework for a variable radius point count survey. A survey set up following this design will lend itself well to standard methods and RIC data forms.

For each survey method, details are provided on how to stratify the Project Area, determine Study Areas, and the type of Design Component(s) that will be used.

Figure 1. RIC species inventory survey design hierarchy with examples.

3.2 Inventory Surveys

The table below outlines the type of surveys that are used for inventorying songbirds for the various survey intensities. These survey methods have been recommended by wildlife biologists and approved by the Resources Inventory Committee.

Table 3. Types of inventory surveys, the data forms needed, and the level of intensity of the survey.

Survey Type	Forms Needed	*Intensity
Encounter Transect & Simple Point Counts	Wildlife Inventory Project Description Form Wildlife Inventory Survey Description Form- General Animal Observation Form- Songbird Encounter Transect & Simple Point Counts Point Count Data Form-Songbirds (optional)	PN
Variable Radius Point Counts	Wildlife Inventory Project Description Form Wildlife Inventory Survey Description Form- General Point Count Data Form- Songbirds Animal Observation Form- Songbird Point Count	RA
Spot Mapping	Wildlife Inventory Project Description Form Wildlife Inventory Survey Description Form- General Animal Observation Form- Songbird Spot Mapping Summary	AA
Any Survey Type	Nest Site Description form - used when a nest is located.	All

* PN = presence/not detected (possible); RA = relative abundance; AA = absolute abundance

There is not enough information on the logistics of surveying particular songbird species to recommend species-specific methods. Therefore, the above methods may be used for surveying multiple species at one time or for surveying a single species.