Douglas Stotz, near left, of the Field Museum in Chicago and Nigel Pitman of Duke University took a biological inventory of a vast roadless area in Peru’s northern Amazon.
Now that we’re out of the field we can draw on a dream team at Field Museum and elsewhere to help us answer some of the harder questions in the reader comment section. For the answers below we received help from Corine Vriesendorp, director of Field Museum’s rapid inventory program; Robin Foster, conservation ecologist at the Field Museum; Jim Louderman, the Field Museum’s insect collection manager; and Günter Gerlach, a curator at the Munich Botanical Garden.
You say you “counted” 860 canary-winged parakeets “this morning.” Please explain your technique.
— P. Desenex, Tokyo
The parakeets typically fly in groups of five to 100 birds. I hear the birds calling as they approach, and count them as they go by. For groups under 20 or so, I can count each individual; for larger groups I count in subsets of five or 10 birds. After counting a group, I write down the number in my notebook and await the next group’s arrival. The general movement is from south to north, so I only count the birds as they are arriving from the south. Afterward, I add up the birds and round the total to the nearest 10, since some of the counting is no more precise than that.