Michigan Department of Natural Resources Wildlife Division - Natural Heritage Program
Background and Purpose
Michigan is home to 13 native species of anurans (frogs and toads). In recent years, many observers have been concerned with the apparent rarity, decline, and/or population die-offs of several of these species. This concern was not only for the species themselves, but also for the ecosystems on which they depend. Frogs and toads, like many other aquatic organisms are sensitive to changes in water quality and adjacent land use practices, and their populations undoubtedly serve as an index to environmental quality.
As a result, the Michigan Frog and Toad Survey was initiated in 1988 on a limited basis to increase our knowledge of anuran abundance and distribution, and to monitor populations over the long term. Over the next few years, a statewide system of permanent survey routes will be developed. Each route will consist of ten wetland sites which will be visited three times annually -- in early spring, late spring, and summer -- by a volunteer observer. At each site, the observer will identify the species present on the basis of their breeding season calls or songs, and make a simple estimate of abundance for each species, using a call index value of 1, 2, or 3. Miscellaneous observations can also be made from locations other than the permanent survey routes.
This cooperative survey is modeled after the very successful Wisconsin Frog and Toad Survey, which began in 1981. Over the years, the Michigan Frog and Toad Survey will provide a wealth of information on the status of Michigan frog and toad populations, and help monitor the quality of our environment.
ESTABLISHING A NEW ROUTE
It is best to scout the area during or just prior to the breeding season to determine wetland suitability. Try to include a variety of wetland types that represents the range of breeding sites available. Consider large vs. small, open vs. shrubby vs. wooded, stagnant vs. flowing, permanent vs. temporary, natural vs. artificial, and remote vs. agricultural vs. urban sites. See the Wetland Types sheet included with these instructions for definitions. Do not avoid ponds that dry up during the year, for they are often productive during spring. Do avoid swift streams, and deep or denuded shores of lakes. Also, avoid areas with heavy background noise, such as busy streets or highways, certain industrial sites, and farms with barking dogs.
Participants sometimes find that one or more of the sites originally chosen turn out to be unsuitable breeding habitat or are poor sites because of unforeseen background noise, access problems, etc. In these cases, it is usually necessary to replace the problem site with a new site sometime after the first survey run, thus voiding the first year's monitoring data. To avoid this, it is recommended that you begin with 11 or 12 sites for the first year and choose only the 10 most reliable sites for the permanent route. At the end of the first year, report results only for the 10 permanent sites. However, wetland breeding sites for amphibians come and go. It is expected that some sites will be better over time (i.e., beavers put in a new pond), and others will disappear (i.e., construction of a new mini-mall). These are to be expected, and the stops should not be changed to incorporate new sites or eliminate sites that are no longer available.
If you want to run more than one route, please feel free to do so. However, if you cannot complete all three surveys on each route, select one route on which to make all three surveys and cover the other routes if you have time. Information from the additional sites will be useful as incidental information.
SURVEYING A NEW OR ESTABLISHED ROUTE
New and experienced observers will find it both helpful to review the tape periodically and to take it along during surveys to help identify uncertain calls. New observers can learn the calls gradually by starting with those species that may be calling during the early spring survey period (wood frog, spring peeper, leopard frog, chorus frog, and pickerel frog), followed by those that begin calling in late spring (American toad, Fowler's toad, cricket frog, and both tree frogs), and finally those species that begin calling during the summer (mink frog, green frog, and bullfrog). It is highly recommended that new observers practice distinguishing calls in the field with the help of a more experienced observer.
Your instructional materials also include a natural history packet which summarizes the geographic range, status, calls, biology, and morphology of each species in Michigan. Use this information to help determine which species are likely to occur in a given region, habitat, and season. Although it is entirely possible that, for example, you may find an unusually early or late singer, or a breeding population outside a species' previously documented range, you should be aware that these unusual occurrences may require special scrutiny or verification.
|Survey Period||Range of Dates||Minimum Air Temperature|
|South Zone||North Zone|
|1. Early Spring||1-20 April||10-30 April||45°F|
|2. Late Spring||1-20 May||10-30 May||55°F|
|3. Summer||1-20 June||10-30 June||65°F|
A tape recorder will enable you to record questionable situations that can be listened to and confirmed at a later time or date. Prescription hearing aids are helpful for listeners who have volume or frequency impairment.
Call Index Value Criteria
1 Individuals can be counted. There is space between calls.
2 Calls of individuals can be distinguished but there is some overlapping of calls.
3 Full chorus. Calls are constant, continuous, and overlapping.
Taking a specimen should be considered a last resort and is not encouraged, especially for the cricket frog.
Contributing Miscellaneous Observations
Other sight or sound observations of anurans or other reptiles and amphibians should be submitted on the Miscellaneous Observations Form. If you wish to run non-permanent survey routes of several wetlands in an area, you may submit the data on a separate copy of the Field Data Sheet, along with a clear description of the locality of each site.
Recommendations for Future Improvements
Your evaluation of the materials and procedures would be greatly appreciated. The first year of this survey was established as a pilot project in order to work out as many potential problems as possible prior to opening the survey to general public participation. Field forms, survey periods, procedures, and natural history information have been closely patterned after the Wisconsin program, often with only essential changes having been made. The idea was not to reinvent the wheel, but simply to modify it to our needs.
??? QUESTIONS ???
If you have any questions, please don't hesitate to call:
MDNR Wildlife Division
THANKS for your help conducting this survey and have an enjoyable field season!