Much of the fieldwork I’ve been doing over the past 3 months has involved surveying birds living in cloud forest fragments throughout the Andes of northern Peru. This may sound relatively straightforward – millions of people around the world love making bird lists after all.  But correctly identifying some 300 bird species in the early morning hours is deceptively difficult.

Most people assume that bird detections occur by sight – you pull up your binoculars and witness a beautiful, exotic tropical bird. But, in reality, tropical birds can be maddeningly difficult to observe. Many tropical species are almost never seen, because they are extremely shy and live in dense, dark vegetation. Hence, nearly all of the birds on my surveys are detected by the remarkably exquisite sounds they make. Some of the songs, such as the extraordinary melody produced by Cyphorhinus thoracicus (Chestnut-breasted Wren), are obvious and stop you in your tracks. Many others, however, are subtle and highly variable and, in some cases, still being described. Add to this the fact that most of my mornings begin at 4:30am with an hour trek up some mountain to arrive at my survey sites by dawn when song activity is at its most intense. Hence, I always make recordings of my surveys to review during the evenings. I use Raven, a program created by the Cornell Lab of Ornithology that converts recordings into visualizations known as spectograms, to crosscheck my written observations and ensure that I am correctly quantifying the bird community. When this is done I will then confront the even more daunting task of turning these field data into estimates of occupancy and density. But, that is a story for another day……………………………

spectogram of the call of the Russet-crowned Warbler
A spectogram featuring the sounds of the Russet-crowned Warbler (Myiothlipis coronata)
Masked Trogon (Trogon personatus)
No doubt what THAT is! Masked Trogon (Trogon personatus)