3. PROTOCOLS

This section reviews the recommended survey methods and provides protocols for inventories of American Bittern, Least Bittern, Virginia Rail, Yellow Rail, Sora and American Coot. Because species detection in these protocols depend on territorial or nesting behaviour by the birds, these survey methods are only reliable during the breeding season.

For most of the species described in this manual, visual surveys will not be effective because rails and bitterns are either difficult to flush, or are only visible in open habitats. Therefore, more pro-active measures such as eliciting responses using call playbacks, or searching for nests with a trained dog will be required.

Recommended methods for each of the species described in this manual are indicated in Table 2. Each method is then outlined in the following sections. The call playback method can be used as both a measure of presence/not detected as well as relative abundance with little adjustment to the sampling design. For measures of nesting density (included under "Absolute Abundance"), trained pointing dogs will likely be required to locate nests within wetlands.

Table 2. Recommended methods for inventory of bitterns and rails in British Columbia at three levels of survey intensity.

Species	Presence/Not Detected	Relative Abundance	Absolute Abundance
American Bittern	Call Playback	Call Playback	Fixed-width Transect
Least Bittern	Call Playback	Call Playback	Fixed-width Transect
Virginia Rail	Call Playback	Call Playback	Fixed-width Transect
Yellow Rail	Nocturnal Call Playback	Nocturnal Call Playback	Fixed-width Transect
Sora	Call Playback	Call Playback	Fixed-width Transect
American Coot	Call Playback	Call Playback	Fixed-width Transect

3.1 Sampling Standards

The following are guidelines for conducting inventory studies on bitterns and rails in B.C. 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. The key to successful comparison between studies is the standardization of the estimated parameters and a measure of the variability (e.g., standard deviation, confidence intervals) associated with the estimated parameter (Fuller and Mosher 1981).

3.1.1 Weather

Weather affects both the observer's abilities and the marsh bird's behaviour. If it is too cold, too wet, or too windy to see, hear, and identify birds, then the survey should not be conducted. Although this section provides guidelines as to what conditions are inappropriate, ultimately the field biologist must decide when her/his ability to survey effectively is compromised. In general, when surveys rely on an observers ability to hear, field work should not be conducted when the wind is greater than 20 km/hr (not greater than Beaufort 3), or when other conditions, such as heavy rain, thunder, traffic, etc. may impair a surveyor's hearing abilities. In addition to interfering with the observer's ability to listen, rain may also place the nestlings at risk of becoming wet and cold if adults are flushed off the nest as a result of survey activities. Therefore, surveys should not be conducted if precipitation is more than a drizzle or light rain.

3.1.2 Time of Year

All of the species described in this manual are migrants (e.g., they move outside of B.C. for a portion of the year) or partial migrants (e.g., they move within the province to lower elevations or to coastal sites). Winter surveys for American Coot and Virginia Rail are possible, but rely on direct counts of individuals based on visual rather than aural identification. Since these species are generally more active, and thus more visible when they are breeding, breeding surveys probably provide a better indication of true population numbers, and more intensive visually-based surveys will be required in the non-breeding season. For these reasons, only breeding-season surveys are recommended and described in this manual.

Breeding bittern and rail counts can theoretically be conducted during late-April to early July in southern B.C. and during late-May to July in northern B.C. However, to standardize survey dates throughout the province, marsh bird surveys should be conducted between 20 May and 5 July throughout B.C. Repeat surveys should be separated by at least 10 days (Marsh Monitoring Program 1997). To determine peak times in breeding chronology for each species, refer to the life history accounts described above, or to the information included in Campbell et al. (1990a; 1990b). Surveys should be conducted as close to peak breeding activity as possible. For aural surveys, peak calling periods (e.g., communication among mates, territorial challenges) are preferred target dates. For transect, nest-finding surveys, inventories should fit local peak nesting periods as closely as possible.

3.1.3 Time of Day

The best time of day to conduct a survey varies by species. American Bitterns are best heard during a dawn survey. There is little information to determine at what time of day it is best to hear Least Bitterns. Yellow Rail are best surveyed at night. Virginia Rail can be sampled at dawn and dusk surveys. Sora can be encountered at any time of the day, but are most responsive in early morning and evening. American Coot can be seen throughout the day, but surveys during the early morning will probably be most productive.

Multiple species surveys of marsh birds should include both morning and evening visits. Morning surveys should be conducted from 30 minutes before to four hours after sunrise (Gibbs and Melvin 1993). Evening surveys should be conducted 30 minutes prior to, and finish at or before sunset (i.e., beginning after 1800 h; Marsh Monitoring Program 1997). Nocturnal surveys for Yellow Rail should be conducted from shortly after dark through to sunrise (Bart et al. 1984).

3.1.4 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 target species, and the objectives of the inventory. Since most provincially-funded wildlife inventory projects deal with terrestrial-based wildlife, the terrestrial Ecosystem Field Form or the Ground Inspection Form, developed jointly by Ministry of Forests (MOF) and Ministry of Environment, Lands and Parks (MELP) can be used when appropriate. Although both of these forms have been used primarily in terrestrial ecosystems, they can also be used in wetlands to describe emergent vegetation and other relevant attributes. Further information about standard habitat data collection is available in the introductory manual, Species Inventory Fundamentals, No. 1.

Wetlands Defined

For the purpose of calculating the area of wetlands and marsh features, it is necessary to define how these features are delineated. The following wetland definition differs slightly from that appearing in the Forest Practices Code Riparian Area Guidebook by including sites which possess either of the following characteristics, but not necessarily both. Under this modified definition, wetlands have either:

• plant communities characterized by species that normally grow in soils which are water-saturated for a major portion of the growing season ("hydrophytes");
• soils with surface peat ("O") horizons or gleyed mineral horizons (Bg or Cg) within 30 cm of the soil surface.

Hydrophytes should make up greater than 20 % or more of the combined cover of low shrub and herbaceous vegetation. Most (>80 %) of the remaining vegetation should be species that are able to grow on water-saturated soils, even though they may not be restricted to these soils. Wetlands do not necessarily have trees, but if trees are present, the canopy should be generally open (< 15 % canopy closure of trees > 12.5 cm DBH).

According to the formal definition, a marsh is a type of wetland, with distinct soil characteristics, as well as seasonally-fluctuating levels of near-neutral to basic surface water. Declining water levels typically expose mudflats and matted vegetation. Emergent vegetation includes grasses, cattails, sedges, rushes, and reeds.

Within the context of this manual, the term "marsh habitat" is used with reference to a vegetated wet area that is periodically or regularly inundated with nutrient rich water up to a depth of 2 m. The area is usually dominated by emergent non-woody vegetation such as cattails, bulrushes, reeds, grasses and sedges. In comparison, swamps, bogs and fens are generally dominated by trees and shrubs.

Some General Wetland Characteristics

A small amount of general habitat data should be collected about each wetland and included in the final report to provide context for the inventory. This should include the following attributes:

• Type of wetland (i.e. fen, bog, marsh, swamp) - refer to the wetlands section in the Riparian Management Area Guidebook (B.C. Min. Environ. and For. Serv. 1995);
• Size of wetland (in hectares);
• Area covered by non-woody emergent vegetation and a calculation of the ratio of non-woody emergent vegetation to open water. Larger wetlands or wetland complexes can have large areas of open water that are obviously unsuitable habitat for most of the bitterns and rails described in this manual. For wetlands like this, you should only describe the shoreline to one metre depth beyond emergent vegetation;
• General description of emergent vegetation - especially to distinguish between woody and non-woody vegetation (e.g., willow versus sedge).

3.1.5 Maps and Aerial Photographs

All RIC survey standards suggest that maps (topographic and TRIM) of the project area be obtained. Maps will help you locate general study areas and general access routes. However, wetlands are seldom mapped in sufficient detail to allow you to determine required survey methods and methods of travel within the wetlands (e.g., use of canoe, or the possibility of shoreline surveys). Recent colour aerial photographs will give you the best information about wetland conditions. Emergent vegetation will be readily visible to allow you to determine the total area of suitable habitat. Unmapped features such as recent seismic lines or old trails will also be visible and will help you decide whether it will be possible to transport a boat into the site.

Photos at 1:15 000 or smaller (1:5 000) scales will be suitable for designing many surveys. To provide field crews with appropriate maps of wetlands, the photos can be copied and enlarged; digitized and printed photos with various sections enlarged will be useful. To make orientation easier for untrained field personnel, individual maps can be created. These maps could show a variety of wetland features including emergent woody stems versus emergent sedge or cattail cover. It is a good idea to invest some time in identifying initial Study Areas and reproducing maps of them to assist field personnel in selecting appropriate and productive areas in which to place marsh bird survey routes.

3.1.6 Survey Design Hierarchy

Marsh bird surveys follow a sample 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 call playback survey for marsh birds. A survey set up following this design will lend itself well to standard methods and RIC data forms.

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

3.2 Inventory Surveys

The table below (Table 3) outlines the type of surveys that are used for inventorying bitterns and rails for the various survey intensities. These survey methods have been recommended by wildlife biologists and approved by the Resources Inventory Committee (RIC).

Inconspicuous waterbirds are undersampled by most standard bird survey techniques, especially those relying on visual or unsolicited call counts (Gibbs and Melvin 1997). Since bitterns and rails are secretive birds that live in relatively inaccessible and densely vegetated habitats, inventory methods are limited to those where birds are heard rather than seen. Therefore, the call playback method that is used for some other RIC standards (e.g., raptor call playback, Resources Inventory Committee 1997a) will also be used for bitterns and rails. The survey described below is essentially a Point Count using broadcasts of tape-recorded birds to elicit responses from target species.

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

Survey Type	Forms Needed	*Intensity
Call Playback	Wildlife Inventory Project Description Form Wildlife Inventory Survey Description Form-General Point Count Data Form- Marsh Birds Animal Observation Form- Marsh Birds Call Playback Wetland Description Form	PN RA
Fixed-width Transect (Nest Count)	Wildlife Inventory Project Description Form Wildlife Inventory Survey Description Form-General Animal Observation Form- Marsh Birds Transect Nest Description Form	AA

* PN = Presence/Not detected (possible); RA = Relative Abundance; AA = Absolute Abundance

Since the calls will be elicited from males (for most species and conditions), a measure of absolute abundance will not be possible using only call response surveys. As an alternative, a measure of absolute abundance is possible using fixed-width (strip) transect surveys if sufficient time and skill are invested. Mark-recapture procedures present another option but are not recommended as an inventory procedure for bitterns and rails. Since most rails are generally difficult to observe, but relatively easy to capture (Bub 1978; Bookhout and Stenzel 1987), capturing and marking the birds would not pose many problems. However, colour tags, neck-bands, or feather marking are not recommended because these conspicuous markers will compromise natural camouflage. Leg bands can be used, but they are not visible because the birds legs are in the water, or can not often be seen through marsh vegetation. Therefore, mark-recapture methods would dictate that birds be repeatedly recaptured to determine population size within a marsh. This would create unnecessary amounts of disturbance. As a result, the measure of Absolute Abundance for bitterns and rails will be limited to a count of active nests within given marshes or areas within a marsh.

3.2.1 Survey Intensity

The same methods are used whether Presence or Relative Abundance of bitterns and rails is desired, and it is recommend that surveys strive for measures of relative abundance whenever possible. The difference between the two levels of intensity is generally just a matter of meeting a few basic statistical assumptions discussed briefly in the introductory manual Species Inventory Fundamentals No. 1.

If the desired objective is to determine whether a species is present within a marsh, then call playback should be conducted until a response is elicited, confirming the presence of the target species. If call playbacks are conducted every 10 days throughout the breeding season and no response is elicited from a target species, then that species can be given a "Not Detected" status for that sample point for that season. A "Not Detected" status for the marsh can be given to that species if sample points are sampled as above, and if they are distributed throughout a marsh at one point for every 5 ha of suitable habitat. If an objective is to evaluate presence between habitat types, then each habitat type should be sampled proportional to availability. For further discussion of Presence/Not Detected surveys, refer to the introductory manual Species Inventory Fundamentals No. 1.

If the desired objective is to compare Relative Abundance of a target species between habitat types, then each habitat type should be sampled with an equal number of point count stations as a balanced design lends itself well to statistical testing. For instance, if you want to determine Relative Abundance of marsh birds (number of birds per plot of marsh habitat) between big (i.e., greater than 50 ha) and small (i.e., less than 5 ha) marshes, further consideration of your sampling design will be necessary prior to establishing field plots. In cases such as this, you may want to either establish a similar number of point count stations, or an equal sample of different size marshes. Further discussion of this aspect of sampling is beyond the scope of this manual, so the reader is referred to the introductory manual Species Inventory Fundamentals No. 1. Project managers interested in this scale of question must also have some statistical design experience to make a Relative Abundance project worthwhile.

Conducting a survey to determine Absolute Abundance of bitterns and rails requires a significant amount of field experience and life history knowledge. The measure of Absolute Abundance is limited to a count of active nest sites. Despite the temptation to do so, do not assume that the number of nests counted is equal to the total population of birds in the Study Area, as it will only include the breeding portion of the population. As well, finding a large proportion of the all the nests present requires a considerable amount of effort and experience both working in marshes and finding marsh birds and their nests by interpreting their behaviour.

3.2.2 Forms for Point Counts

Two of the forms required for marsh bird point counts have specific roles which may not be readily apparent. For this reason, the uses of each of these forms is described below.

1. Point Count Data Form - Marsh Birds

• This form is used only in the field to map bird locations and their responses to call playback. It is similar to data sheets used for songbird point counts (Resources Inventory Committee 1997b). However, there is only one circular plot for the entire 10 minute count rather than separating the count into three different time periods. One of these sheets is completed at each point each time it is visited (i.e., for each design component visit).
• As this form is for field purposes only, information collected on it will be transcribed onto a Animal Observation Form - Marsh Bird Call Playback. However, Point Count Data Forms should be kept on file by the Field Manager.

2. Animal Observation Form - Marsh Bird Call Playback

• Information from the Point Count Form- Marsh Birds is transferred to this form. One form is used to summarize all observations at one point count station, for one visit. Record each bird detected on a line on the Animal Observation Form - Marsh Bird Call Playback.
• From these forms total counts by species can be tallied for each visit to a point. An index of abundance for each species for each point can also be calculated.