How Many Butterfly Trees Do You Count? Discussion of Challenge Question #5 Students from New Jersey and Vermont including Ruby, Tucker, Phoebe, Joanna, and Amanda gave this question some thought. Their estimates ranged from 57 to 9,990 butterfly trees. "You just make as good a guess as you can," said the students! When we saw the students' answers (most of which were much higher that our estimate of 391), we realized that we should have told you this: The orange you see in certain trees are monarch butterflies! Your challenge is to decide which trees to include in the colony, draw or imagine a "perimeter" line around the colony, and count the trees within it. (Scientists mark perimeters so they can estimate colony size.) When you do this, you can see how difficult it is; the trees vary so much. Making these types of estimates is even harder for scientists in the field. There, the butterflies, weather, trees, and even the scientists are constantly changing. Here are variables our student reporters said could make it hard to count butterfly trees: What other factors can affect monarch colony estimates in the field? Click here >> "We noticed that in some places on the pictures the trees are clumped together more tightly than others." "There were some areas on the picture that had no trees on them." "Some trees would hold more butterflies than other trees." "Weather can make it difficult. The butterflies move around." Here is how we looked at the problem: We drew this outline in red around the monarch colony. (Click image for a larger view.) Would you have drawn it differently? As you can see, it's VERY hard to determine the exact borders of a monarch colony. You have to make many subjective (personal) decisions. For example, you have to decide which trees to include or exclude when you draw the perimeter. Other people might not include the same trees we did.   Copyright 2002-2006 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form