Russ C. Weeber, Jon D. McCracken, and Charles M. Francis, Bird Studies Canada, P.O. Box 160, Port Rowan, Ontario N0E 1M0
The Marsh Monitoring Program (MMP) was initiated in 1994 by Long Point Bird Observatory (now Bird Studies Canada) and Environment Canada in response to a recognized need for information on the status and trends of marsh breeding amphibian and bird populations, particularly in some highly impacted Great Lakes coastal wetlands (Areas of Concern). The MMP is an international, volunteer-based program focused on surveying birds and calling frogs and toads in coastal and inland marsh habitats in the Great Lakes basin. The program’s main objectives are to: monitor populations of marsh birds and amphibians, both spatially and temporally; investigate habitat associations of marsh birds and amphibians; contribute to assessments of Areas of Concern; and to disseminate results and conclusions to the public and the scientific community.
Several aspects of alternative protocols were explored in 1993, including: fixed-distance and unlimited distance survey methods; morning and evening surveys; mid-season (late June) and late-season (mid-July) visits; survey durations from 5 to 20 minutes; and detection rates prior to and after broadcasts of taped bird calls. The selected protocol was tested in Ontario in 1994 and expanded to the whole basin in 1995.
Under the current MMP protocol, participants select survey routes consisting of one to eight stations. Routes must be surveyed within a single evening, by a single surveyor. Stations are 100 m radius semi-circles, positioned along the wetland edge and containing marsh vegetation (i.e. non-woody, emergent plants). Stations surveyed for birds must be at least 250 m apart and those sampled for amphibians must be at least 500 m apart. Participants are free to conduct surveys for marsh birds, amphibians, or both groups but are encouraged to commit to bird surveys only if they can correctly identify at least 50 common bird species, with particular emphasis on those associated with wetlands. All volunteers receive a Training Kit containing: a protocol booklet; data forms; a broadcast tape used to elicit calls from the more secretive marsh bird species; and an instructional tape with examples of the songs and calls of marsh birds and amphibians most likely to be encountered in the Great Lakes basin. The protocol booklet contains instructions for establishing survey routes, conducting surveys for amphibians and marsh birds, and summarizing wetland habitat characteristics. The broadcast tape includes calls of Virginia Rail (Rallis limicola), Sora (Porzana carolina), Least Bittern (Ixobrychus exilis), Pied-billed Grebe (Podilymbus podiceps), and the paired calls of Common Moorhen (Gallinula chloropus) and American Coot (Fulica americana), with the call of each species separated on the tape by a silent listening period. Marsh Monitoring Program participants also receive an annual newsletter that summarizes survey results and includes articles on marsh ecology, amphibians and marsh birds.
Each station surveyed for marsh birds is visited twice each year between May 20 and July 5, no less than 10 days apart, in the early evening, with surveys ending at or before sunset. Each station is surveyed for 10 minutes, with the 5-minute broadcast tape played during the first half of the survey. All birds observed or heard within a 100 m radius semi-circular sample area are counted, and birds detected flying over or outside the station area are tallied separately.
Marsh Monitoring Program participants also describe general habitat characteristics of their survey stations between May and early June. Within the station area, volunteers classify the percent cover of five major habitat types (e.g. herbaceous emergent vegetation or open water/submergents), of submergent plants within open water areas, and of the four dominant plant genera within the emergent vegetation zones. Participants are also asked to classify the wetland size and adjacent upland land use, and to note obvious human influences such as dykes or channels.
Marsh Monitoring Program routes are distributed throughout the Great Lakes basin, in Ontario and in each of the Great Lakes states. Between 1995 and 1997, 425 routes have been surveyed during at least one of these years. Almost 40% of these routes have been surveyed for both amphibians and marsh birds, with the remaining routes split about equally between amphibian routes and bird routes. Of routes established in 1995, 49% have been monitored in three years, 11% in 1995 and 1996 only, 6% in 1995 and 1997 only, and 34% were surveyed in 1995 only. Of those routes established in 1996, approximately half were surveyed again in 1997.
Guided by a formal scientific evaluation of the program and the survey protocols, and incorporating lessons learned during four years of administering and conducting the surveys, we are currently considering a variety of refinements to the program design. Issues concerning route allocation, survey intensity and statistical power are discussed in a companion paper (Francis and Weeber), others are presented here. Of particular concern is a clear definition of the sampling objectives of the survey, which has implications for both the selection of survey routes and selection of stations along routes. Should the survey be intended to sample a particular wetland type (i.e. dominated by a specific vegetation assemblage) or a particular vegetation assemblage within aquatic systems in general (e.g. herbaceous emergents in wetlands or along lake edges)? If station selection is based on particular vegetation characteristics, how should the protocol address temporal changes in plant composition and density within the station area? Ideally, survey stations would be randomly allocated within selected strata (e.g. within wetland or vegetation types). How should station allocation strategies for volunteer-based, long-term programs integrate constraints such as those imposed by a required minimum distance between stations (i.e. to avoid overlapping counts); differing accessibility to potential stations; and limitations in surveyor motivation and knowledge of the waterbody surveyed? Similarly, how can assessments of wetland habitat characteristics and landscape context measure the habitat attributes actually involved in marsh bird habitat selection most effectively, and at appropriate spatial and temporal scales? Unfortunately, habitat selection criteria are not well understood for marsh bird communities, and the design of these assessments can be further constrained by surveyor’s motivation and knowledge of wetland habitat measures, and by access to information ranging from wetland nutrient status through regional land use patterns.
Stimulated by a concern for wetlands and wetland dependent wildlife,
interest in marsh bird monitoring appears to be increasing, as shown by
the terms of reference for this workshop. Bird Studies Canada is interested
in exploring the need and practicality of developing an expanded version
of the MMP, applicable across Canada as well as the Great Lakes basin.
Implementation of any such expanded program will be contingent on sufficient
interest and funding.
Marshbird
Monitoring Workshop