MATCHING TEST Two tests of your matching ability have been provided. The first is considerably easier than the second. We strongly recommend successfully completing the easier test (with 100% correct) before attempting the more difficult one. Please send your results for either test to cherzog@nycap.rr.com. Easier Test The easier test consists of groups of three images. Two were made by the same foot but one is from a different foot. Your task is simply to determine which two images match. Note: this test is described as "easier", not because the tracks are all easy to match. Some are easy and some are definitely not. It's "easier" because you know ahead of time that two, and only two, of the tracks can be matched. This is in contrast to the real world of analyzing tracks gathered in the field, where you get no guarantees. For a simulation of what that's like you can try the master-level test. [Test A1, Test A2, Test A3] [Test B1, Test B2, Test B3] [Test C1, Test C2, Test C3] [Test D1, Test D2, Test D3] [Test E1, Test E2, Test E3] [Test F1, Test F2, Test F3] [Test G1, Test G2, Test G3] [Test H1, Test H2, Test H3] Master-level Matching Test Instructions The prints in the master-level matching test are all realistic examples of the prints that wild fishers leave at track plates. A scenario description is included that contains clues that can help a bit if you apply some knowledge of fisher ecology. The use of these clues is not necessary to perform the test, but it does add realism and will make the process go faster. Only prints from a single fisher are present on any sheet of contact paper i.e., having the same date and location. This is representive of the idea that no fisher is likely to visit a station after the bait is eaten by another, which appears to be a realistic limitation based on experience examining many track plates. It is very helpful to keep track of the matching process in a spreadsheet, such as that shown here. Print it out, copy it into MS Excel, or use whatever medium you find convenient. Once you decide which prints belong to which fisher, make up a name and mark it in the “animal” column. Master Test Hints Each detection (a particular combination of date and location) will feature footprints of a single animal. While visits to a single station on repeated days are most likely to be from the same animal, you cannot assume that this will always be the case. Likewise, nearby stations are more likely to be visited by the same animal but, since you don’t know the limits of their home ranges, this is also not something you can count on completely. Before attempting to match two prints, first try to assess their overall appearance. Decide if the general flow of the rows is at least similar. If not then you either have two different animals or at least one of the prints is distorted. You will have to decide which. Sometimes one section will be distorted and another not, so try first to match the areas where the rows seem to flow in similar pattern. Also, look for distinctive, atypical features that sometimes make matching very easy. Concentrate your initial efforts on the best quality prints. The spread sheet includes a subjective indication of print quality (poor, fair, good) Once you get a match, give the animal a name and search the two date/locations that provided the matching prints for a good quality image of the opposite foot. After you have identified a high quality left and right foot image for an animal the whole process becomes easier. Having more than one of each helps even more. If a date/location has no good quality prints, save that until you have matched all of the good ones first and then go back to it. We have yet to see two good quality images made by the same foot that could not be readily matched. Notice which portions of the prints are the clearest. Most prints have at least some areas where debris and smearing obscure things you would like to examine. Again, this is realistic. The ideal image is one where the dots are large but still mostly separate. Concentrate on the main portion of the pad, which is roughly trapezoidal in shape. The “wings” on either side are much harder to match due to a greater tendency to be distorted. If you want to give these a try then feel free. It works sometimes, but less often than when using the main part of the pad. This master-level test might take 2 hours or more to complete, depending on your skill level. Master Test Scenario and Images
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