Older accounts of Mai Po credit a 1,500-hectare wetland to a conservation charity and count nearly 500 species of bird in it. Both figures attach to the wrong thing. The Ramsar site — Mai Po Marshes and Inner Deep Bay, designated on 4 September 1995 and covering 1,540 hectares — is managed by the government's conservation department; the charity manages the 380-hectare Mai Po Nature Reserve inside it. About 460 species have been recorded across the wetland, some fifty of them globally threatened or near-threatened. And the access rules changed four months ago: from 24 July 2026 the police closed-area permit is no longer needed for Mai Po, though a conservation department permit still is.
Two areas, two managers, and the names that go with them
Three names cover overlapping ground here, and conflating them is what produces most of the wrong figures.
The Mai Po Inner Deep Bay Ramsar Site is the international designation, listed as "Mai Po Marshes and Inner Deep Bay", designated on 4 September 1995 and covering 1,540 hectares. It is managed by the government's Agriculture, Fisheries and Conservation Department. Government material describes it as over 1,500 hectares; the two figures are the same site stated to different precision rather than a disagreement.
The Mai Po Nature Reserve sits inside that site, covers 380 hectares, and has been managed by WWF-Hong Kong since 1983. The charity's habitat works, hides and boardwalks are within the reserve; it does not manage the wider wetland. Its own name matters for accuracy: it styles itself WWF-Hong Kong, and government writes it out as the World Wide Fund for Nature Hong Kong. "World Wildlife Fund" is an old name and the wrong one.
The Mai Po Marshes Restricted Area is the statutory layer, listed in the schedule to the wild animals protection legislation. Entering it without a permit from the Director of Agriculture, Fisheries and Conservation is an offence. "Mai Po Marsh" on its own is not an official name for anything.
What is recorded there
About 460 bird species have been recorded — roughly four-fifths of all the species known in Hong Kong — of which some fifty are globally threatened or near-threatened, including five critically endangered and seven endangered. Deep Bay supports on average 46,000 to 66,000 waterbirds in winter. The site regularly holds more than one per cent of the global or regional populations of black-faced spoonbill, great cormorant and pied avocet, and it is the type locality for thirteen invertebrate species. WWF-Hong Kong names Saunders's gull and Nordmann's greenshank alongside the spoonbill among species of global conservation concern, together with the globally threatened four-spot midget dragonfly.
The black-faced spoonbill is the species the site is best known for, and its story is more interesting than a simple rarity. It was downlisted from critically endangered to endangered in 2000. Fewer than 300 birds were counted in the late 1980s; the 2023 census found 6,633. Deep Bay — Hong Kong together with the Futian reserve in Shenzhen — held an average 7.5 per cent of the world wintering population between 2018 and 2022, with a peak of 527 in the winter of 2022–23. A species action plan runs from 2024 to 2028 with nineteen actions and a review at the end. Even so, population viability modelling still predicts decline by 2050 from habitat loss and climate change: a conservation success that is not yet secure.
The gei wai
The gei wai are intertidal shrimp ponds backing the mudflats, some of them with reedbeds, and Mai Po is the only place in Hong Kong where they are still operated. The management plan is more precise than that summary: traditional operation is maintained in part of the reserve, while other ponds have been converted into high-tide roosts or freshwater habitat for waterbirds. Trash fish are stocked in some to reduce cormorant predation on the commercial fishponds nearby.
So they now do two jobs at once — a surviving piece of traditional aquaculture, and a managed habitat tool. That dual purpose is the reason they are presented as an example of the wise use of wetlands rather than as a relic.
Getting in, and the permit that changed in July 2026
Access is controlled and has two routes, neither of them spontaneous.
The permit route is the Mai Po Nature Reserve Entry Permit, issued by the conservation department and generally valid for a year. Type A admits the holder to the reserve but excludes the boardwalks and bird hides that WWF-Hong Kong builds and manages outside the boundary fence. Type B covers those facilities and additionally requires an annual authorisation obtained in advance from WWF-Hong Kong. Type A carries no annual quota; Type B is capped, allocated by ballot when oversubscribed, and applications for the current year have closed. Eligibility is tied to a recognised purpose — birdwatching, conservation, education or scientific research — supported by documents or a written statement, and applications are made in writing.
From 24 July 2026 the police closed-area permit is no longer required for the Mai Po part of the former Frontier Closed Area. That removes one of the two permissions a visitor used to need, and it is recent enough that most published accounts still describe the old position. The conservation department's permit is unaffected.
The route for an ordinary visitor is a guided visit run by WWF-Hong Kong or another non-profit, booked in advance against a quota, with the organiser arranging the permit. Visits follow a designated trail past the gei wai, the boardwalk and the hides. The Peter Scott Visitor Centre and the Mai Po Education Centre open daily from 09:00 to 17:00, closing at Christmas and Chinese New Year.
Two things could not be established from any official source and so are not stated here: a minimum age for entry, and a named official entry point. Both are worth confirming with the organiser when booking.
When to go, and why the official sources disagree
They genuinely do. The government's own page on the reserve says spring and autumn are the best seasons for birdwatching; WWF-Hong Kong says autumn and winter, putting "tens of thousands" of migratory birds in those months and giving spring and summer to insect life and the gei wai shrimp.
The two reconcile once the question is split. Peak numbers are a winter phenomenon — the 46,000 to 66,000 waterbirds counted in Deep Bay are a winter count. Peak variety belongs to spring and autumn, when passage migration moves through. Neither source names specific months, and no page should invent them.
Threats, and what is being built alongside
The management plan records the pressures without euphemism: siltation and sedimentation in Inner Deep Bay; mangrove colonisation, including the invasive Sonneratia; the invasive climber Mikania; water quality in Inner Deep Bay and in two of the gei wai, tested monthly — a proposal to discharge treated wastewater from a nearby development into them was dropped over high phosphate; avian influenza surveillance; and climate change. Development is controlled through outline zoning plans, the environmental impact assessment legislation and a town planning guideline.
The larger change is the Northern Metropolis, and the official framing of it is conservation alongside development rather than instead of it. A Wetland Conservation Parks System was written into the development strategy in 2021, with a policy of resuming private wetlands and fishponds of ecological value; over 600 hectares of fishponds inside and outside the Ramsar site were conserved across ten years under management agreements. A feasibility study released on 24 October 2024 found the system workable and named four proposed parks — Sam Po Shue, an expansion of the existing wetland park, Nam Sang Wai, and Hoo Hok Wai with Sha Ling and Nam Hang — each zoned for biodiversity, eco-friendly aquaculture, fisheries enhancement and visitors. Sam Po Shue comes first.
Dates to watch
Sam Po Shue Wetland Conservation Park is the nearest item. Tenders for the first stage were invited on 10 July 2026 and closed that September, covering site formation and infrastructure including about 30 hectares of gei wai and ecologically enhanced fishponds; the works were scheduled to begin in December 2026 and to run about thirty months, which takes them to roughly mid-2029. Land resumption notices were posted in July 2025.
The black-faced spoonbill action plan runs to 2028 and is reviewed at the end of it, which will give the first real test of whether the Deep Bay wintering share is holding.
And the Type B permit ballot reopens annually, so the closed state of the current year's applications is a recurring condition rather than a permanent one.
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