Step 1: Understanding the Question:
In wildlife management, "census" means counting animals. An "indirect census" is a method where you don't count the animal itself, but rather something the animal leaves behind.
Step 2: Detailed Explanation:
• Indirect Census Methods: These are used for animals that are shy, nocturnal, or live in dense forests where they are hard to see. Common signs include pugmarks (tracks), scat/dung, calls, and nests.
• Dung Count (B): This is a classic indirect method. By counting the number of dung piles (pellets) in a specific area and knowing the "defecation rate" (how many times an animal poops per day), scientists can estimate the population density of deer, elephants, etc.
• Direct Census Methods: Methods like "Transect counts" (C) or "Spatial counts" involve actually sighting and counting the individual animals as the researcher moves through the forest.
• Conclusion: Dung count is the only option that relies on "signs" rather than direct "sighting."
Step 3: Final Answer:
Dung count is a well-known method of indirect census.