17 de julio de 2024

A woodpecker paradise, and 1000 birds

A little-known fact about Prague is that the city, like much of the Czech Republic, is a paradise for woodpeckers (and for their afficionados). Even city parks such as the Petřín Hill and the Královská Obora parks are rich in mixed woodlands which attract at least six species of woodpecker, as well as their congeners such as Nuthatches and Treecreepers. The Middle Spotted Woodpecker is a central European species which requires mature deciduous forest. In the Královská Obora park today, a photogenic individual perched for some time on a the trunk of an oak tree.
According to the eBird database, this woodpecker was the 1000th species I have recorded in a total of 1900 checklists. This is not exactly a list of species I have seen, since it includes some 'heard only' species such as owls, and excludes various birds which I saw before the eBird era and did not record accurately enough to enter in the database retrospectively. But when I began using eBird to record sightings in 2017, 1000 birds seemed like a reasonable goal. At the time, it was agreed that there were around 10000 bird species in the world, so that 1000 would be a representative sample of 10%.
Now for the interesting part. Despite ongoing extinctions, the number of known bird species is rapidly rising. Thanks largely to genetic sequencing, it has become clear that birds which look alike do not necessarily belong to the same species, and vice versa. 'Cryptic species' appear similar but do not interbreed because they are separated by behaviour and vocalizations as well as geography. The Chinese Blackbird, for example, looks much like the Eurasian Blackbird but differs in its vocalizations and behaviour. The Lesser Sand Plover no longer exists, but turns out to have been an amalgam of two similar-looking species that are not particularly closely related, having diverged around 2 million years ago. Even the familiar Eurasian Wren is likely to be 'split' into several species.
As a consequence of these 'splits', a recent estimate suggests that there may be around 18,000 bird species -- almost twice as many as was believed less than ten years ago. This is a valuable lesson in what Konrad Lorenz called scientific humility: all knowledge is provisional, and students of the natural world should not be too confident about what we think we 'know'.

Publicado el 17 de julio de 2024 a las 04:48 PM por stephenmatthews stephenmatthews | 6 observaciones | 0 comentarios | Deja un comentario

11 de abril de 2024

Kingfishers at Po Toi

With its sheltered bays and creek, the island of Po Toi attracts various kingfishers. Two Common Kingfishers were present at the 'creek' today, even if it was reduced to more of a muddy puddle. The creek is one of the few places in Hong Kong where Ruddy Kingfishers are occasionally seen on passage.
A surprise was in store today for visiting UK birder Nick Brown, who had not even got off the ferry when he spotted a kingfisher on the rocks which did not look at all like the British one. He soon identified it as a Collared Kingfisher, causing quite a stir among local birders who were able to view it from the ferry pier and even from the departing ferry.
The Collared Kingfisher is a common species in its core range, as in Malaysia and Singapore, but a rare vagrant in Hong Kong: David Diskin's authoritative database lists only five previous records between 1990 and 2019. It also occurs as a vagrant in Taiwan and the Ryukyus, presumably arriving from the Philippines.

Publicado el 11 de abril de 2024 a las 12:00 PM por stephenmatthews stephenmatthews | 2 observaciones | 0 comentarios | Deja un comentario

12 de febrero de 2024

Endemic birds thriving in Otago

From previous visits to Aotearoa New Zealand, I was expecting endemic land birds to be few and far between, with introduced British and Australian species dominating the landscape. So it was a pleasant surprise to find the tables turned in favour of the natives in the Otago Lakes District. The first bird I encountered on venturing outside was a Tui, perched at the top of a conifer. Then on entering a patch of manuka/kanuka scrub, an unfamiliar bird popped up. It proved to be a South Island Tomtit, actually one of the Australasian robins belonging to the genus petroica. The orange chest markings indicated a male, springing into action to investigate or challenge the intruder.
After sitting down to investigate some bird calls emanating from the scrub, I was soon surrounded by curious passerines investigating the intrusion into their territory. First to arrive were South Island Fantails, displaying at point-blank range by fanning their tails. They were soon joined by a chattering group of Pipipi or Brown Creeper, a relative of the endemic Whitehead and Yellowhead which inhabits scrub across the South Island. Also in the scrub were a Grey Gerygone, the most widespread of the endemic land birds, and a Silvereye, a species of whiteye from Australia. A Swamp Harrier, the commonest raptor in New Zealand, was hunting over the pine forest.
The resilience of the native passerines owes much to the use of trapping to control introduced predators such as stoats and rats. This is a step towards the goal of making the islands predator-free by 2050.

Publicado el 12 de febrero de 2024 a las 11:58 PM por stephenmatthews stephenmatthews | 8 observaciones | 0 comentarios | Deja un comentario

13 de enero de 2024

An uncommon gull at San Tin

Large flocks of Black-headed Gulls winter in Deep Bay and forage around the fishponds of San Tin, occasionally accompanied by other gulls. In January 2024 they have been joined by an immature Common Gull, which in Hong Kong is enough of a rarity to attract a crowd of birdwatchers and photographers. The main subspecies breeding in northeast Asia, known as the Kamchatka Gull, is rather larger that the European Common Gull. A single Whiskered Tern, the only tern species to be seen locally in winter, was fishing over the fishponds, along with a Pied Kingfisher. Also present were wintering ducks including Pintail, Shoveler and Garganey, Common Snipe, and Green, Wood and Common Sandpipers.
The winter of 2023-24 may be the last at San Tin as we (and the wintering birds) know it: a substantial chunk of the wetland area is to be the site of a San Tin Technopole, part of the Northern Metropolis development. Substantial loss of habitat and disturbance due to construction are to be expected, though a wetland park is included in the proposal. The gulls, at least, should be sufficiently adaptable to continue using the site.

Publicado el 13 de enero de 2024 a las 11:16 AM por stephenmatthews stephenmatthews | 8 observaciones | 0 comentarios | Deja un comentario

04 de enero de 2024

The curious tailorbirds

Tailorbirds are named for their nests which are built inside a cradle 'stitched' together from large leaves. Hong Kong has two "tailorbirds", though phylogenetic research reveals that they are not closely related.
The Common Tailorbird is a resident species, common in urban as well as country parks. It will often "scold" intruders with its insistent call.  
Our other tailorbird is the Mountain Tailorbird, one of several forest species which have recolonized Hong Kong as the forest cover has increased and matured. According to Birds of the World, it favours "bushy thickets, bamboos and hanging tangles within broadleaf evergreen forest, especially along watercourses." This is exactly where it can be found wintering along streams on the campus of the Chinese University campus, as well as at Lung Fu Shan. As its name suggests, it prefers mountain habitats, although these sites are only 100-200 meters above sea level.
As my "record shots" attest, this is quite a secretive species, typically located by its distinctive piercing whistle or chattering call. However, both tailorbirds are curious creatures which will often approach an observer, offering a brief opportunity for a photo. After satisfying their curiosity they will disappear into the forest or return to their foraging.

Publicado el 04 de enero de 2024 a las 09:40 AM por stephenmatthews stephenmatthews | 2 observaciones | 0 comentarios | Deja un comentario

16 de septiembre de 2023

Return of the 'Swintail' snipe

Following record September rainfall in Hong Kong, sports fields have been flooded, forming ideal habitat for passing snipe, and just at the right time of year too: groups of snipe pass through on migration in April and September, having been observed at Kowloontsai Park on April 24, 2020, September 6, 2020, and from (at least) September 8 to 10, 2023. On these occasions there were respectively 2, 4 and 6 birds present. Since snipe are known for their 'site fidelity', revisiting the same spots each year, it seems likely that the same family group is involved.
Now for the difficult part: which species of snipe are these? Local expert John Allcock has identified them as either Pin-tailed or Swinhoe's Snipe, both of which have shorter bills and subtly different markings than Common Snipe. But these two species are so similar that separating them requires either sound recordings or photos showing a spread tail in exquisite detail, failing which, they are known as 'Swintail' snipe. Since photos from Kowloontsai to date do not suffice to distinguish the two species, the puzzle looks set to remain for another year.

Publicado el 16 de septiembre de 2023 a las 11:36 AM por stephenmatthews stephenmatthews | 1 observación | 0 comentarios | Deja un comentario

16 de julio de 2023

In Aoteroa: half a native avifauna

Aotearoa ("Land of the long white cloud") is the traditional Maori name for the North Island of what is now Aotearoa New Zealand. For the naturalist, it is a fascinating but frustrating place. Like Hawaii, it is fascinating because the isolation of the islands has given rise to a wealth of endemic species; and frustrating because so many of these are reduced to a marginal existence. Also like Hawaii, Aotearoa has gone through two waves of extinction: one following Polynesian settlement of the islands, and another following European colonization. The extinctions brought about by these two waves amount to around half the native land birds, from the flightless moas and the eagles which preyed upon them to the iconic huia and piopio. The gaps have been filled by introduced species. Especially bizarre is the suite of British birds, half a world away from home -- Eurasian Starling and Blackbird, Song Thrush, Chaffinch, Goldfinch and Yellowhammer -- juxtaposed with Australian species like Eastern Rosella, Common Myna and Australian Magpie.
Of the surviving endemic species, a few are widely distributed around the main islands. These include the Grey Gerygone, New Zealand Fantail, Tui, New Zealand Scaup and Red-breasted (New Zealand) Dotterel. The New Zealand Pigeon and Bellbird have a patchy distribution on the mainland. The remaining endemic land birds have been extirpated from most of the mainland, surviving only in sanctuaries -- offshore islands like Tiritiri Matangi, or enclosed areas of the mainland from which predatory mammals have been eradicated, like Shakespear Regional Park. In creating these sanctuaries Aotearoa has acted more swiftly and decisively than Hawaii. The sanctuaries have proved so successful that surplus birds can be translocated to new sanctuaries. The success has prompted a bold "moonshot" project: to eradicate predators from the whole of the country by 2050. Local efforts towards this goal are already bearing fruit, with native birdsong returning to more and more areas of the country.
Aotearoa has another claim to ornithological fame -- as the seabird capital of the world. Thousands of shearwaters congregate in the fish-rich waters of the Hauraki Gulf north of Auckland, and can be viewed from ferries or from the shore, including Auckland's North Shore and the Whangaparaoa peninsula. Although few breeding colonies of shearwaters and petrels remain on the main North and South islands, offshore island colonies have benefited from eradication of rats and other predators.

Publicado el 16 de julio de 2023 a las 02:35 AM por stephenmatthews stephenmatthews | 28 observaciones | 0 comentarios | Deja un comentario

07 de junio de 2023

The Pheasant-tailed Jacana

With their long feet and toes, Jacanas are built to walk on floating vegetation and have quite specific habitat requirements, ideally ponds with water lilies or similar plants on which to walk. Formerly there were many such ponds in the New Territories and Pheasant-tailed Jacanas (水雉 'water pheasant', Hydrophasianus chirurgus) bred around Mai Po until the 1970s. Since then, Jacanas have occurred mostly on passage, typically stopping over in wetlands such as Mai Po and Long Valley in May.
In order to tempt the birds back to breed, an ideal Jacana habitat has been created at the Lok Ma Chau wetlands. Visible from the Lok Ma Chau MTR platform, the lily pond is part of a mitigation project to compensate for the loss of wetland to make room for the new rail connection. But the habitat is small, and the Jacanas first have to find it. This year a bird has instead taken up residence in the unlikely setting of the Cyberport on Hong Kong Island, which has an artificial lake at its centre. The two levels of the lake are separated by a concrete structure, effectively forming a catwalk on which the Jacana has been strutting, to the delight of the assembled photographers.
Let us hope the Jacanas eventually return to breed in more suitable habitat. Like Greater Painted-snipes, female Pheasant-tailed Jacanas are polyandrous, keeping a harem of males to whom they delegate the childcare.

Publicado el 07 de junio de 2023 a las 10:57 AM por stephenmatthews stephenmatthews | 2 observaciones | 0 comentarios | Deja un comentario

16 de mayo de 2023

Rewilding reaches Kai Tak

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.

Publicado el 16 de mayo de 2023 a las 12:11 PM por stephenmatthews stephenmatthews | 8 observaciones | 0 comentarios | Deja un comentario

15 de mayo de 2023

A chorus of cuckoos

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.

[In May 2024 at Fowlmere in Cambridgeshire, one cuckoo was indeed producing a falling 4th, while others were producing a minor or major 3rd. It appears that the interval varies between individuals and gradually widens before reaching a major 6th in June. So there is a basis in nature for Mahler's treatment of the song].

Publicado el 15 de mayo de 2023 a las 01:44 PM por stephenmatthews stephenmatthews | 1 observación | 0 comentarios | Deja un comentario