Yuren Cao / December 3, 2019
Reserva Ecológica Costanera Sur was first established as a nature reserve in 1985, and was later recognized by BirdLife International as an Important Bird Area. It is without doubt the best reserve in the city of Buenos Aires not only for its unique location, but also for its stunning biodiversity.
It sits beside the most modern area of the city and lies on the coast of River Plate, encompassing three lagoons, all of which are artificial. And it also has a variety of trees, grasses, and shrubs. These characteristics truly make the reserve stand out from other nature reserves and parks in the region.
Five months ago I decided to make use of my winter vacation in Buenos Aires to learn more about its nature. As a result, I was determined to go to Reserva Costanera Sur periodically to fully discover its beauty and investigate its avifauna. In the span of two months (July and August), I visited this reserve more than 20 times. When I sit down and reflect on this experience months later, I was amazed by how much I have learn from this experience.
Winter can be harsh in the city, but the birds didn’t seem to care about the freezing wind that denuded the trees of their leaves so ruthlessly. As soon as the sunlight penetrated the branches, warblers and wrens started their activities in the bushes. Walking down the empty trail, the minuscule movement of the bushes was magnified, exposing the presence of a House Wren, or perhaps a Masked Gnatcatcher, both are commonly found in the reserve.
I stopped at a platform that were surrounded by trees and waited quietly. Looking through the branches, I started to notice things that I was previously oblivious of. At the levels of my eyes, a tiny Golden-crowned Warbler was performing impressive acrobatics, showing its golden yellow underpart. Its flexible and intricate movements rendered it nearly impossible to be photographed. It never fails to leave me irritated with a blurred photo in my camera.
Everything started to become alive. But this time, it was not the birds that I was noticing, it was the sound. I heard the high-pitched notes from the Straneck’s Tyrannulet and White-crested Tyrannulet. Note the difference between their sounds — it is the only way to tell them apart. I heard the rapid trill from a Rufous Hornero as it was flying to its nest, the dirge from a Rufous-bellied Thrush, and the loud whistle from a Golden-billed Saltator when it was flying away, as if it was startled by my presence. But how could I have startled the bird, when the only sound I made was the sound of my clothes rubbing as I was moving? Oh, I see, the leafless trees couldn’t block the sound of the birds, and it couldn’t block the trace of my presence either.
It always fascinates me how many things one can discover by simply stopping one’s footstep sometimes. All of these things that were elusive to our senses start to reappear when you are willing to wait and observe.
There are much, much more going on in the trees of this reserve. Variable Oriole is among the most frequent visitors of these trees. It is not difficult to find this middle-sized black bird clinging on the branches, sometimes showing its red patches on the shoulder.
A even more common visitor is the Narrow-billed Woodcreeper. It is a guarantee to see it clings to the trunk and climbs up and down in search for insects under the bark. One can never be tired of its pale, decurved bill. First I thought that it must be a kind of woodpecker, but it really is a subfamily of the ovenbirds, which has little to do with the woodpeckers. The real woodpeckers, however, are usually busy working on its new nests around the reserve. It is not difficult to see a pair of Checkered Woodpecker flying about some times.
[To be continued…]