Diario de stephenmatthews

Spring in Hong Kong is announced by a veritable cacophony of cuckoos. First, as early as late February, come the resident Asian Koels (噪鹃, "noisy cuckoos") and hooting Greater Coucals (褐翅鴉鵑) whose songs inspire their onomatopoeic names. In April the Plaintive Cuckoos (八聲杜鵑) join in with their falling, accelerating 8-syllable song. By early May, the Large Hawk-Cuckoos (鷹鵑) with their feverishly repeated 3-syllable song are heard throughout our woodlands but rarely seen except at Mai Po, where they are joined by the Indian Cuckoos (四聲杜鵑) with their 4-syllable song, sometimes transcribed as 'one more bottle'. Adding to the cuckoo chorus are other birds which mimic their songs, notably the Oriental Magpie-Robin which does a passable imitation of the Plaintive Cuckoo.
A surprise in recent weeks has been the addition of two 'Common' or Eurasian Cuckoos, perching and occasionally singing around the police post at Mai Po. They appear to be a male and a female, presumably a pair on northbound passage, with the female showing a rufous throat. In much of Europe, the two-syllable song of these birds marks the arrival of spring and gives rise to the onomatopoeic name "cuckoo". It makes its way into Beethoven's 'Pastoral' Symphony and even inspired a piece of its own, Delius's 'On hearing the first Cuckoo in Spring'. Curiously, late in the breeding season the song shifts from a falling major 3rd to a falling major 6th, giving rise to the rhyme "The Cuckoo comes in April, sings his song in May, changes his tune in the month of June" and to further musical possibilities. In his 1st Symphony Mahler even transforms the interval into a 4th, taking a certain poetic license in order to echo the primeval falling 4th of his opening bars.

Following the successful revitalization of the Jordan Valley Channel, Hong Kong's Drainage Services Department has undertaken another 'green river' project at the Kai Tak River, formerly known as the Kai Tak Nullah (drainage channel). The river still flows though a concrete channel but rocks have been added to create elements of a natural river. While increasing the drainage capacity of the channel, vegetation has been planted along the banks. To date, the most extensive revitalization has affected the 'midstream' section of the river between Tai Shing Street and Prince Edward Road East.
As in the case of the Jordan Valley Channel, ecological effects are already visible. Butterflies and birds forage in the foliage. Numerous Black-crowned Night Herons and a few egrets use the riverbanks, while a recent observation seems to show a migrating Malayan Night Heron on one of the newly reinstated rocks. This would explain why I seemed to hear a Malayan Night Heron calling at night in Kowloon City last May.
Most encouraging of all is the presence of several species of fish, including snakehead and mullet, attesting to the water quality. To those old enough to remember the 'notorious' Kai Tak Nullah, this a remarkable transformation.