Cape York to Cape Grenville Islands (23966)
Australia, Australasia
Site overview
KBA status: confirmed
Global KBA criteria: D1a, D1b
Year of last assessment: 2022
National site name: Cape York to Cape Grenville Islands
Central coordinates: Latitude: -11.4647, Longitude: 143.0776
System: marine, terrestrial
Elevation (m): 0 to 17
Area of KBA (km2): 29.27667
Protected area coverage (%): 100.00
KBA classification: Global
Legacy site: Yes
Site details
Site description: This KBA (29 km² in total) consists of a string of nine important seabird/shorebird islands (or island groups) in the northern Great Barrier Reef, from Womer Cay opposite the tip of Cape York to the Sir Charles Hardy Islands opposite Cape Grenville. This KBA hosts a globally significant feeding aggregation of Grey-tailed Tattler 'GTT' (Tringa brevipes) and a globally significant nesting aggregation Torresian Imperial Pigeon 'TIP' (Ducula spilorrhoa). All islands which are important for Trigger species are included in the KBA: Hannibal (13.3 ha; TIP), Boydong & Little Boydong (25.4 ha; GTT & TIP), Cairncross (14.2 ha; TIP), Wallace (5.4 ha; GTT), Cholmondeley (4.6 ha; GTT), Milman (30.2 ha; GTT), Magra (6.4 ha; GTT), Saunders (11.6 ha; GTT), Sinclair (6.8 ha; GTT). These are small low level sandy cays totalling 1.18 km² land area with variable amounts of harder coralline substrates, grass, herbs and vines, and some larger islands have Pisonia grandis trees. Islands are part of either Denham Group National Park or Wuthathi (Saunders Islands) National Park (Cape York Peninsula Aboriginal Land). The exception is Hannibal Island, which is not part of a terrestrial national park. The KBA is entirely within the Great Barrier Reef Marine Park and World Heritage Area.
Rationale for qualifying as KBA: This KBA hosts a globally significant non-breeding population of Grey-tailed Tattler Tringa brevipes (KBA Criterion D1a) and a globally significant breeding population of Torresian Imperial Pigeon Ducula spilorrhoa (KBA Criterion D1b). Grey-tailed Tattler migrate south from their Siberian breeding grounds along the East Asian-Australasian Flyway to feed in high densities within Cape York to Cape Grenville Islands. Site counts over the last 10 years confirm that over 1% of the global adult population of this species predictably occurs in the KBA, triggering under Criterion D1a. Three islands within this KBA predictably support high densities of Torresian Imperial Pigeon nests. Surveys for this species have not been conducted across all three islands at once, but singular island counts often exceeded 1% of the Australian population size. The KBA is estimated to host ~41,000 individuals total, making this site likely the second largest aggregation of this species in the world, and triggering a KBA under Criterion D1b.
Additional biodiversity: Species formerly listed as Important Bird Area Triggers nest in this KBA: Lesser Crested Tern, Roseate Tern and Bridled Tern. Critically Endangered Hawksbill turtles also nest on several islands within this KBA, however there is insufficient data at this stage to include them as a trigger species.
Manageability of the site: This site is made up of two terrestrial National Parks: Denham Group National Park and Wuthathi (Saunders Islands) National Park (Cape York Peninsula Aboriginal Land). The former is managed by Queensland Parks and Wildlife Service, and the latter is joint
Other site values: Wuthathi, Gudang and Yadhaykenu people are the Traditional Owners of this site
Delineation rationale: The KBA boundary consists of 1 km radius circles drawn around each island/cay, except for Cairncross Islets which is an ellipse (of equal area to a 1 km radius circle) to better cover the elongated shape of that islet group. Overlapping Boydong and Little Boydong 1 km radius circles have been merged.
Habitats
Land use: The KBA is currently managed by Wuthathi Aboriginal Corporation, the Great Barrier Reef Marine Park Authority and Queensland Parks and Wildlife Service for a variety of uses, but primarily preservation of natural and cultural values of this World Heritage Area. Uses include: tourism, education, scientific research and cultural heritage / traditional use. Use restrictions are specified by the following Great Barrier Reef Marine Park Zones: Hannibal Island - Commonwealth Island (GBRMPA) (IUCN II); Magra Islet - Habitat Protection (IUCN VI) & General Use (IUCN VI); Boydong, Cholmondeley, Hannibal, Saunders, Sinclair & Wallace - Marine National Park (IUCN II); Milman - Preservation (IUCN IA)
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Forest | 5 | |
| Marine Coastal/Supratidal | 15 | |
| Marine Neritic | 75 | |
| Marine Intertidal | 20 | |
| Forest | 5 | |
| Grassland | 20 | |
| Marine Coastal/Supratidal | 5 |
Threats
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Climate change & severe weather | Habitat shifting & alteration | Ongoing | |
| Climate change & severe weather | Storms & flooding | Ongoing | |
| Invasive & other problematic species, genes & diseases | Invasive non-native/alien species/diseases | Ongoing | |
| Pollution | Garbage & solid waste | Ongoing | |
| Pollution | Industrial & military effluents | Oil spills | Only in the future |
| Human intrusions & disturbance | Recreational activities | Ongoing | |
| Climate change & severe weather | Storms & flooding | Only in the future |