Beidaihe - Bird Migration Hub of the Orient

Beidaihe Migrants Suffering Declines

By the end of May, the spring migration is almost over; the birding is often sparse. But given fallout conditions — which in spring can include rain, or a threat of rain — there may still be good counts. On 7 June 1991, the town's easternmost headland, Lighthouse Point, heaved with reed-warblers, Acrocephalus warblers and other songbirds.

Among the late-spring migrants are marsh birds — Yellow Bitterns Ixobrychus sinensis and Schrenck's Bitterns I. eurhythmus, Baillon's Crake Porzana pusilla, reed-warblers, and Locustella warblers, which time their journeys to coincide with the late growth of the emergent vegetation they lurk in.

At the end of May and in early June, there is the chance of what may be the last megatick of spring, the little known, now endangered Streaked Reed-Warbler Acrocephalus sorghophilus (right).

Though, as with any migration watchpoint, the birding varies from one year to the next, it rarely disappoints. `When people hear what we've seen this spring,' said one birder last year, `it will blow their minds.'

But mind-blowing or not, the migration at Beidaihe has a sobering side. Numbers of several species have fallen — dramatically in some cases — and the migration we see today may be only a shadow of the migration early this century.

I write `may be' because, although information on birds in the Beidaihe area earlier this century is relatively plentiful, it is often hard to compare it with recent observations. It is not easy to judge whether numbers of a species have changed — and if they have changed, to what extent. Despite this problem, for many migrants, I know of no better information for assessing population changes. Beidaihe is probably the best studied migration watchpoint in east Asia, with studies dating back to 1910.

The first study was by British consul John D.D. La Touche, whose work on birds during his postings in China, and comprehensive — and still useful — A handbook of the birds of eastern China were significant contributions to the country's ornithology. Through his own observations, and the specimens and sightings of collectors employed by the British Ornithologists' Club's Migration Committee, he worked on the birds at the nearby port of Qinhuangdao from 1910 to 1917.

Sadly, in reporting his results, La Touche rarely gave numbers, but instead used comments such as `abundant', `common', or `scarce'. It is hard to guess whether his uses of these terms would agree with ours; how would he have reported the migration at current levels? Because the terms `abundant' and `very abundant' appear through his papers far more often than we would use them today, was La Touche too liberal in using them?

A member of one of our survey teams argues that he was. I am not convinced; La Touche's writings suggest he was level-headed. If so, several species have undergone a steep, sad decline in numbers. Indeed, La Touche wrote of `long streams' of migrants passing down the coast in autumn: by today's standards, his description seems exaggerated.

We are on safer ground in making comparisons with the work of Hemmingsen, who gave fuller accounts of the species he recorded, often with some numbers, sometimes with seasonal totals. Again, there are problems: Hemmingsen was a lone observer — albeit helped by servants whom he paid for finding flocks of passing cranes, geese and other birds — working under the constraints of Japanese occupation. The habitats have changed: Beidaihe today is radically different from the small town he would have known, a brash resort that has expanded as China's economy has boomed.

Difficulties aside, comparing our results with those of La Touche and Hemmingsen paints a bleak picture. Though the data may be poorer, it seems the situation is much the same as in North America, with migrants in decline, and several causes for the dropping numbers, all rooted in a devastatingly huge human population.

As you would expect, habitat damage and destruction ranks high on the list of causes. That last megatick of spring, Streaked Reed-Warbler, occurred in fair numbers during La Touche's time, but is rare today. Thought to breed in Manchurian wetlands — no one yet knows for sure — it winters in the Philippines, and it may be here that the problems lie, as several of the wetlands it favoured have been `reclaimed'.

The warbler is far from being alone as a wetland bird in decline. Hemmingsen saw up to 10,000 Bean Geese passing in autumn; even with teams of observers monitoring visible migration in shifts, our best count is only around 4000. Nor have the flights of Oriental White Storks and Common Cranes we have witnessed matched the peak numbers recorded by Hemmingsen. Flocks of Tundra (Bewick's) Swans Cygnus columbianus bewickii are smaller and fewer — there have been none in recent autumns. Northern Pintail Anas acuta, which La Touche regarded as `perhaps the most abundant of the larger ducks' is uncommon; Baer's Pochard Aythya baeri — `extremely abundant' in autumn, according to La Touche — is now uncommon at best. Baillon's Crake is apparently scarcer, so too Eurasian Coot Fulica atra, Little Curlew, Pallas's Grasshopper-Warbler and Japanese Marsh-Warbler.

Baikal Teal Anas formosa perhaps deserves special mention; its population has not declined or plummetted, but crashed. It used to be abundant in east Asia — Hemmingsen once saw a flock of 1000-2000 at Beidaihe. Now it is uncommon throughout most of its range: at Beidaihe, there have been just 15 individuals recorded since we restarted studies in 1985. The reasons for the crash are unclear. Possibly, the chief cause is hunting.

Another anomaly among the dwindling wetland birds is Sanderling Calidris alba. Generally — because of increased coverage, or vanishing habitat elsewhere? — we have found shorebirds in higher numbers than Hemmingsen reported. Sanderling is different. Hemmingsen saw it `in flocks of, say, 30-100'; but our recent records are sparse, with single figures only. I wonder if it is a victim of disturbance on its wintering grounds, which for `our' population are chiefly along the coasts of Southeast Asia. A beach specialist, Sanderling may have lost out to resorts built for sun-worshipping tourists.

Nearer to Beidaihe, the coastal wetlands have suffered. Hemmingsen reported Eurasian Oystercatchers Haematopus ostralegus osculans — which are of an endangered eastern race — at one of Beidaihe's estuaries in June. Perhaps they bred; but no longer. Developments have left even the more resilient Little Terns Sterna albifrons pressed for space.

Fish ponds and shrimp ponds have spread like wildfire along the coast south of the town. The saltmarshes they have replaced will have been used by birds such as cranes, geese, and Great Bustards. All these birds still stop over — regularly, judging by our few visits — on an area of saltmarsh and rough fields that remains, sandwiched between shrimp ponds, at the Luanhe estuary.

This area also holds [now, 2005: held, as area reportedly ruined] perhaps a hundred breeding pairs of Saunders's Gulls. Numbering only around 2000, and endemic to China as a breeding bird — its breeding grounds were first discovered only in 1987 — Saunders's Gull must be among the country's most threatened vertebrates. It is known to breed only at three sites in addition to the Luanhe: on the coast of southern Manchuria, in the Yellow River Delta, and north of Shanghai. At each of these, the shrimp ponds and other developments are moving in; already, the largest colony may have been destroyed by a reservoir, built to irrigate fields in a supposed wildlife sanctuary.

There may be another disaster story unfolding: the the Three Gorges Dam, an overblown project that will flood a region that has, said a newspaper report, been compared to the Grand Canyon. The dam will disrupt the flow of the Yangzi, threatening species unique to the river such as the Yangzi River Dolphin and the Chinese Sturgeon. The mudflats at the river mouth will be affected. And the summer floods that fill huge lakes along the river valley may be reduced.

These lakes are of immense importance for waterfowl, especially in winter, when a corner of one lake — Poyang — may hold over a quarter of a million ducks, geese, swans, and cranes, including Siberians. China's wintering Siberians, `lost' to ornithology since late last century, were rediscovered at Poyang in the winter of 1980-1981; a reserve was established, and many more birds arrived to enjoy protection from rampant hunting. The Siberian Crane numbers at Poyang increased substantially, from 140 when they were first found, to a peak of 2900. Their boom may be short-lived.

Another cause of falling populations is deforestation. It is, however, hard to tell if its impact has been similar to wetland destruction, as gauging population changes of Beidaihe songbirds from past and recent records is more difficult than it is for waterfowl. But in one case — Siberian Blue Robin — the evidence seems irrefutable: there has been a serious decline. And there is a likely culprit: destruction of the tropical forests in its winter range.

`In the spring ... this species swarmed Beidaihe about the middle of May and some time after,' Hemmingsen wrote of the Blue Robin; sometimes, they were `too numerous to count'. And though Hemmingsen saw relatively few in autumn — because of the denser foliage — there is a report of a great fall of them at Beidaihe. One of the Beijing-based birding missionaries, G.D. Wilder, related rather casually that, `On September 10 [1923] the Siberian blue chat ... was in the fields and on the grassy hillside among small pines in thousands....' Only in one recent spring have numbers been high, with 250 one day — impressive, but not swarming; they have otherwise been easy to count. And autumn numbers have been modest; the fall Wilder described now seems like a remote fantasy.

Wintering in Southeast Asia, the Siberian Blue Robin is especially vulnerable to the deforestation as, at least in Thailand, it prefers lowland forests, which are invariably the first to be felled. Other migrants have surely suffered in much the same way. [Added early 2004: Problems surely worsening, with reports of increased logging in Indonesia (and elsewhere) to supply China's demand for timber.]

The carnage looks set to spread to the north, to the breeding grounds of many migrants. With the break-up of the Soviet Union, and a more open Russia eager for revenue, Korean, Japanese, and other companies have been quick to offer their help in stripping the Siberian forests.

It may not be long before the effects of deforestation will show more clearly in the numbers of migrants occurring at Beidaihe. Within decades, the migration we know today could become as much an impossible dream as the migration in La Touche's time is to us now.

Hunting worsens the blight of habitat loss and destruction. La Touche reported that at the end of last century egrets were devastated by plume-hunting. In the decades since his work, their populations may have recovered, but only slightly, suggesting hunting still takes a toll. [2005 update: egrets are becoming fairly common along the coast, with a substantial egretry now at Beidaihe.] Hunting has surely had a large impact on waterfowl — it may have devastated the population of Baikal teal, which has a habit of flying in dense flocks with predictable daily movement patterns. Perhaps it has also impacted Great Bustards, which similarly pass Beidaihe in smaller flocks than before, as well as many other birds.

An article in the February 1993 issue of China Environment News was headlined, `Hunters decimate Boyang's wild birds.' Each winter, according to the article, 300,000 ducks are killed by poisoned bait at Poyang (Boyang). (In turn, deaths of people poisoned by eating the ducks are common.) Waterfowl are also shot, even though this is `forbidden by the state'. They are sold in markets, with some — particularly rarer, supposedly protected species — destined for restaurants in southern China and Hong Kong. The market price per duck is around US$3. Geese cost almost US$10 each, while swans fetch roughly US$30 — more than many Chinese earn in a month.

Reflecting the hunting pressures they face, Beidaihe migrants are invariably wary. During the surveys at the town, we have seen gulls and thrushes shot for food, some other birds shot at purely for sport, and children with sling shots letting fly at warblers, bluetails, redstarts, and other songbirds that come within range. [2005 update: Now unusual to see this, thanks to education and law enforcement work.]

Trapping is widespread; despite laws against it, finches, buntings, and Northern Goshawks Accipiter gentilis are trapped at Beidaihe. [2005 update: there is still some trapping, but this is far less blatant, as the local government has made some efforts to catch and punish bird trappers.]

Often, it is hard to gauge the impact of trapping. But one example — from Thailand, but involving migrant songbirds that pass through Beidaihe — shows that it can be devastating. During surveys of a wildlife market in Bangkok during the late 1960s, Yellow Wagtails Motacilla flava and Yellow-breasted Buntings were abundant, with totals of 16,721 and 87,209, respectively. Yet a repeat survey from December 1987 to December 1988 found none of either species. The likely reason is trapping at their communal roosts.

While both these species are still common at Beidaihe, they are by no means as abundant as La Touche described (Yellow Wagtail passed in `immense flocks'; Yellow-breasted Bunting swarmed in the crops). Trapping may be the reason here, too. Maybe many were — and still are — trapped in south China, where the Yellow-breasted Bunting, known as the `rice bird', is popularly eaten. Maybe the wagtails and buntings trapped and sold in Thailand included birds that had traveled through Beidaihe.

Pesticides, which in many parts of east Asia are often applied liberally and carelessly, have probably reaped their own, grim harvest of wild birds. I know of no serious work on their effects on bird populations in China — whose Silent Spring is yet to be written. So, as too often when looking for causes for declines in Beidaihe migrants, we can do little better than guess when pesticides are to blame. Probably, they are chiefly responsible for steep declines in the numbers of Black Kites Milvus migrans and Rooks.