Estimating numbers in flocks of birds is a skill that birders need to practice, but we rarely get a chance to test ourselves. We see a flock, guess the total number, and write it down. We might be off by a large margin, but we’ll never know.
Here is a quiz (and more to come) that will give you a chance to test your accuracy. These are lentils, photographed against a white background, but they simulate birds pretty well, I think.
One estimating technique you can try is to count the “flock” in segments. That is, count ten to see what a group of ten looks like, then superimpose that group across the flock, counting in groups of ten. Or you can just “eyeball” the flock of lentils and take a guess. Good luck, and feel free to offer suggestions or encouragement in the comments.
Test your number sense
Question 1 |
50 Hint: too low | |
80 Hint: close, just a little low | |
100 | |
120 Hint: close, just a little high | |
150 Hint: too high |
Question 2 |
45 Hint: way too low | |
60 Hint: too low | |
100 | |
140 Hint: a little high | |
180 Hint: too high |
Question 3 |
60 Hint: too low | |
90 Hint: too low | |
110 Hint: a little low | |
150 | |
190 Hint: a little high |
This was good!! Keep em coming. & for future reference do not ask me to count birds this fall !!
Interesting… this is definitely a skill I could use some practice with.
Thanks for this, awesome idea… Anxious to see the other quizzes that will be arriving- the practice is needed & very much appreciated!!
Good practice. Will be useful with CBCs coming up. Question #2 may have a glitch.
Thanks Mike, The quiz works fine for me. Let me know if you still have a problem with it.
ARBIB, R. 1972. On the art of estimating numbers. Am. Birds 26:706-712
Thanks, Mr. Sibley. I also experienced a glitch w/ question 2. When I clicked on D there was no response. Then when I tried E a checkmark appeared.
These are great exercises, and I really need to practice this skill. This is a cool way to do it.
My only quibble: What level of precision is necessary? To my mind, there is no significant difference between the numbers 90 and 100 in this context. Even 100-120 are within the expected margin of error, I would think. If my estimates of birds in flight were regularly within 50% of the actual number, I’d call myself skilled enough. Am I setting the bar too low?
Hi Tim, Thanks for the feedback. I agree, if you’re getting within 50% consistently that’s pretty good. I did try to avoid making these quizzes too “nit-picky” with answer choices as close together as 90 and 100, so I’ve just fixed that one. I also added “hints” that show up to give instant feedback on which way you missed, as I think that is helpful also.
This is great! I regularly do waterfowl surveys and have volunteer citizen scientists that help. I have used these exercises for years to hone my skills and encourage my teams to do the same. The more precise the count the better the data… I guess I just like to set the bar high. One twist I like to throw at people (myself included) to challenge them is to use mix sizes and colors i.e. mixture of pinto beans, lentils, rice etc. tossed onto a gray background.
These exercises are great because I don’t have to count them and I don’t have to pick up the mess.
Thanks – this is a really good test and great feedback for knowing if we are getting better.
Very good. But it would be nice to have some with several thousand “birds”. Those are the tough ones!
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