After Colombia, Peru is the country with the world’s second largest bird list. The quintessential question is, how so many species of birds can be found within a country that is not the largest in Latin America. The answer lays in the country’s diversity of habitats. The more habitat types the more species of birds and other wildlife will occur there. In terms of bird diversity, Peru is not only blessed with a diverse geography, but also encompasses a substantial portion of the Amazon Basin within its political boundaries.
The rainforest on the Amazon Basin “east-to-west”, extends from the shores of the Atlantic Ocean up to the heights of the east slope of the Andes. The lowland rainforest (below 300 meters of altitude) features a high diversity of habitat and microhabitats, many of which are the result of a network of rivers that split the region into separate fragments of land. Amazonian rivers not only add a distinctive set of habitats to the lowland rainforest, but also act as effective geographical barriers. Indeed, the Amazon River and its major tributaries constitute a sudden stop to the geographic ranges of many Amazonian birds.
Seen from above, the lowland rainforest seamlessly extends upwards on the east slope of the Andes to an elevation of about 3,500 m above sea level. A closer look though, reveals that unlike its lowland counterpart, the east slope is the Andes largely unbroken. No barrier or any other feature interrupts or fragments the solid green of the east slope of the Andes. An indeed the habitat diversity on the east slope of the Andes, is nowhere near that in the lowland rainforest.
Then, how are there so many species of birds on the East Slope of the Peruvian Andes? Well the strategy here is different. A large number of species are packed in altitudinal bands. This means species use similar habitats, but segregate themselves in elevational bands along the altitudinal gradient. For instance, one species will be found between 1,600 to 2,300 m of altitude and is replaced by another species of the same genus above or below, or drops out altogether. A similar scenario repeats itself as many times as species inhabit the east slope of the Andes.
Birds to see in Peru
There are many birds to see in Peru. The average distributional band-width for Andean birds is 1,300 m and can be as narrow as 920 m. Taking as an example the Antpittas of the genus Grallaria in Southeast Peru, 6 different species occur from the summit of the Andes to the lowland rainforest. Antpittas occur in altitudinal bands replacing each other along the altitudinal gradient. For visitors birding the east slope of the Peruvian Andes, the Manu Road is probably the best place to experience this avian phenomenon, where just about the entire length of this little traveled road needs to be explored to maximize the chances of seeing most of the birds occurring there. Antpittas are skulkers by nature, hence and it is helpful learning their distinctive songs and calls. Traveling along the Manu Road making random stops, one could tell the elevation just by listening to which of the six species of Antpitta is singing nearby.
The same pattern repeats itself for other birds. Some genera are represented by multiple species along narrow altitudinal bands and others are represented by fewer species in wider bands. When preparing for a birding trip to the east slope of the Peruvian Andes, knowing this and other fascinating details of the birds’ natural history certainly add more meaning and enjoyment to a birding trip in Peru.
Altitudinal ranges and main vocalizations of the six species of antpittas of the genus Grallaria occurring along the Manu Road in Southeast Peru.
| Stripe-headed Antpitta | 4,600 – 3,500 m | |
| Rufous Antpitta | 3,700 – 2,400 m | |
| Undulated Antpitta | 3,500 – 2,250 m | |
| Red and White Antpitta | 3,00 – 2,100 m | |
| White-throated Antpitta | 2,500 – 1,500 m | |
| Scaled Antpitta | 1,750 – 650 m |
Altitudinal ranges and figures were obtained from the book: Birds of Peru: Thomas S. Schulenberg, Douglas F. Stotz, Daniel F. Lane, John P. O’Neill, and Theodore A. Parker III (2007)