Marine IBAs in the Pacific

The IBA process was developed in the terrestrial context, and the global criterion were designed to cover the four primary cases where important bird populations could be recognised and defined:

a) where rare or threatened species were found in significant numbers (IBA Criterion A1);

b) areas of importance for species which were restricted in their range or habitat types (range- or biome-restricted species, Criteria A2 and 3, respectively);

c) areas with important concentrations of individuals from one population, either through a large proportions of a global population being present (threshold of 1% of the global population, Criterion A4i and A4ii for different taxon groups respectively), or where a large number of individuals congregated within a limited time (with thresholds of 20,000 birds, Criteria A4iii and A4iv for specific taxon cases, respectively).

Recognising that species in the marine environment had needs for greater environmental management and protection, the IBA criteria were adapted to cover the particular cases of marine birds (Oiseck 2004).

“Marine Birds” are grouped into two distinct taxon groups for the purposes of IBA analyses. The species covered in this study fall into two groups: a) Seabirds, including all petrels and albatrosses, storm petrels, gannets and boobies, penguins, tropicbirds, frigate birds; and b) Waterbirds, including terns and noddies, gulls, cormorants, skuas. We reviewed 156 species, of which 48 were used to derive foraging range estimates (Annexe 1).

The ways in which birds use the marine environment has been studied (Oiseck 2004), and has resulted in the definition of four categories in which marine birds populations could be assessed against the IBA criteria (Box 1).

Box 1. Four types of marine Important Bird Area defined by Oiseck 2004. These characteristics of habitat use are used to apply the global IBA criteria (After BirdLife International 2010).

Seaward extensions to breeding colonies. These extensions, which are used for feeding, maintenance behaviours and social interactions, are limited by the foraging range, depth and/or habitat preferences of the species concerned. The breeding colonies themselves will have, in most cases, already been identified as IBAs, which will therefore require their boundaries to be extended into the marine environment. The seaward boundary would, as far as possible, be colony and/or species-specific, based on known or estimated foraging and maintenance information.

Non-breeding (coastal) concentrations. These include sites, usually in coastal areas, which hold feeding and moulting concentrations of waterbirds, such as divers, grebes and benthos-feeding ducks. They could also refer to coastal feeding areas for auks, shearwaters etc.

Migratory bottlenecks. These are sites whose geographic position means that seabirds fly over or round in the course of regular migration. These sites are normally determined by topographic features, such as headlands and straits.

Areas for pelagic species. These sites comprise marine areas remote from land at which pelagic seabirds regularly gather in large numbers, whether to feed or for other purposes. These areas usually coincide with specific oceanographic features, such as shelf-breaks, eddies and upwellings, and their biological productivity is invariably high.

Information sources and methods

The kind of information available to describe the populations of marine birds and their occurrence differs from that of many terrestrial species. Information about breeding numbers can be more accurate or readily accessible than for land birds, as marine birds are typically colonial in their nesting habits. For ground-nesting species, such as terns, boobies, albatrosses, counts of breeding numbers can be quite accurately and readily estimated, often to within 10-20% of the true population size. However, estimating population sizes can be problematic for burrow-nesting, and in some species cases, such as diving petrels or prions, no reliable estimates of global population sizes exist.

The at-sea distributions of marine birds are known to widely differing degrees. The ranges from their breeding colony tend to be restricted during the breeding season. Seabirds are central-place foragers with altricial young, meaning that adult birds are constrained to foraging from their nest during the breeding season. During the breeding season, density of birds around the breeding colony declines exponentially with distance from the site (D. Filippi, unpublished data). This fact has been exploited in the definition of the IBAs that are seaward extensions of breeding colonies (BirdLife International 2010). The foraging range of a species from its nest may therefore be used to define the area most exploited for coastal species, such as terns, boobies, gulls, and cormorants.

For wide-ranging species, such as petrels and albatrosses, there may be significant areas of concentrated foraging activity associated with hotspots of marine productivity or marine bathymetric features, such as shelf breaks or sea-mounts. Therefore, the colony-focussed concentrations of feeding activity are not as readily applicable for these species. In these cases, other information, such as at-sea counts and remote tracking of individuals can be used to define areas where significant concentrations of seabirds are found on a regular basis (BirdLife International 2010). The at-sea distributions of many Pacific seabird species are unknown, and the number of species studied with remote tracking is limited at this time to a few dozen populations and species of the larger-sized birds in this group (BirdLife International 2004).

Identifying areas of most intensive use by marine birds

We have reviewed the information available about seabird populations and their distributions in this study, and identified candidate areas for designation as marine Important Bird Areas (mIBAs) for the Pacific. We chose only those sites where a marine bird population triggered IBA critieria A1 or A4iii and applied the Seaward Extensions methodology defined by BirdLife for boobies, terns, cormorants and penguins (BirdLife 2010). We defined the areas that would be identified as candidate mIBAs at a radius of 35 km from a colony for terns, 115 km for boobies, 15 km for Megadyptes penguins[1], 200 km for Eudyptes penguins and 16 km for cormorants.

For albatross and petrel species, we identified areas of significant utilisation for species with IUCN threatened species listings of EN, VU, and NT based on satellite tracking data (criteria A1). This was applied only for New Zealand breeding species of albatross and Procellaria petrel (data were reviewed for 15 species. Data were used to identify candidate mIBAs where two or more seasons of remote tracking data were available for a species, or where two or more colonies or life-stages of birds had been studied. This ensured that any offshore areas identified were places that are regularly used. Areas overlapped considerably between species, thus the areas represented in the figures represents information for multiple species, combined, although any area would qualify as an IBA on the basis of a single-species dataset. These areas overlapped to a great degree with the zones identified in the Seaward Extension analysis described above, applied for penguins and cormorants. Therefore, the zones defined as candidate mIBAs for New Zealand were defined using the more detailed data from remote tracking data.

We assessed the quality of the original estimation studies using expert opinion. We chose data that was recorded from 1980 onwards (less than 30 yrs old).

Geographic scope of the study

The scope of the study was to cover the Pacific Island Countries, Territories and States (PICTS) in Polynesia, Melanesia and Micronesia[2]. Several desk reviews of the scientific literature describing marine bird breeding populations were available, and were used to identify sites that qualified as IBAs on the land (BirdLife International 2006, 2008; Environmental Consultants Fiji 2007; Gupta 2007a, b, c, d, 2008; Holm et al. 2008; Pacific Environmental Consultants 2010; Parr 2008a, b, c, d, e; Pierce et al. 2009, Saunders 2006). These sites were analysed to describe mIBAs for the following PICTs: Clipperton, Federated States of Micronesia, Fiji, French Polynesia, Kiribati, Marshall Islands, New Caledonia, New Zealand, Northern Marianas Islands. Data from a further set of PICTs were examined, but did not allow identification of mIBAs at this time: Guam, Nauru, Nuie, Palau, Pitcairn Islands, Samoa, Solomon Islands, Tonga, Wallis and Futuna and Vanuatu. Marine IBAs for Australia have already been defined (Dutson et al. 2009).

Provisional nature of the assessments

Our aim was to produce a first ‘fairly comprehensive’ set of marine sites that could be considered for listing as IBAs. All the sites identified are strong candidates to become mIBAs, as they satisfy the IBA criteria, and data quality guidelines determined by BirdLIfe for marine sites (Birdlife International 2010). Other sites may be identified through time, as data are reviewed against additional IBA criteria (e.g. A4i, A4ii, relating to where 1% of global populations of waterbirds and seabirds are found, respectively), or when new data become available for additional sites and populations. Further consultation with stakeholders in the PICTS, and additional analyses may lead to a modification of this set of sites described here.

Annexe 1. Marine and waterbird species for which Foraging Range information was used to identify Marine IBAs centred on breeding grounds.

5 separate radii were used, 35km for terns and noddies, 16km for cormorants and shags, 200km for Eudyptes penguins, 15km for Megadyptes penguins and 115km for gannets and boobies.

Scientific Name	Common Name	IUCN 2010	Foraging Range	Foraging Range Used In IBA Analysis
Anous minutus	Black Noddy	LC	36	35
A. stolidus	Brown Noddy	LC	95	35
A. tenuirostris	Lesser Noddy	LC	36	35
Gygis alba	Common White Tern	LC	46	35
G. microrhyncha	Little White Tern	LC	46	35
Procelsterna cerulea	Blue Noddy	LC	36	35
Sterna albifrons	Little Tern	LC	36	35
S. albostriata	Black-fronted Tern	EN	36	35
S. anaethetus	Bridled Tern	LC	45	35
S. bengalensis	Lesser Crested Tern	LC	36	35
S. bergii	Great Crested Tern	LC	15	35
S. caspia	Caspian Tern	LC	65	35
S. dougallii	Roseate Tern	LC	36	35
S. fuscata	Sooty Tern	LC	36	35
S. hirundo	Common Tern	LC	7	35
S. lunata	Grey-backed Tern	LC	36	35
S. nereis	Fairy Tern	VU	36	35
S. nilotica	Gull-billed Tern	LC	36	35
S. paradisaea	Arctic Tern	LC	36	35
S. striata	White-fronted Tern	LC	36	35
S. sumatrana	Black-naped Tern	LC	36	35
S. vittata	Antarctic Tern	LC	36	35
Phalacrocorax atriceps	Imperial Shag	LC	16	16
P. campbelli	Campbell Island Shag	VU	16	16
P. carbo	Great Cormorant	LC	17	16
P. carunculatus	New Zealand King Shag	VU	16	16
P. chalconotus	Stewart Island Shag	VU	16	16
P. colensoi	Auckland Islands Shag	VU	16	16
P. featherstoni	Pitt Island Shag	EN	16	16
P. fuscescens	Black-faced Cormorant	LC	16	16
P. melanoleucos	Little Pied Cormorant	LC	16	16
P. onslowi	Chatham Islands Shag	CR	16	16
P. punctatus	Spotted Shag	LC	16	16
P. ranfurlyi	Bounty Islands Shag	VU	16	16
P. sulcirostris	Little black Cormorant	LC	16	16
P. varius	Large Pied Cormorant	LC	16	16
Eudyptes chrysocome	Southern Rockhopper Penguin	VU	205	200
E. pachyrhynchus	Fiordland Penguin	VU	222	200
E. robustus	Snares Penguin	VU	222	200
E. schlegeli	Royal Penguin	VU	222	200
E. sclateri	Erect-crested Penguin	EN	222	200
Megadyptes antipodes	Yellow-eyed Penguin	EN	14	15
Morus capensis	Cape Gannet	VU	115	115
M. serrator	Australasian Gannet	LC	115	115
Papasula abbotti	Abbott's Booby	EN	114	115
Sula dactylatra	Masked Booby	LC	115	115
S. leucogaster	Brown Booby	LC	115	115
S. sula	Red-footed Booby	LC	115	115

For a full list of the species considered click here.

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[1] The candidate areas for penguins and most of the cormorant populations are not represented on the maps as the areas are continuous with the zones identified by the remote tracking analyses.

[2] Data from the following PICTs was examined in the study Fiji, Federated States of Micronesia, French Polynesia, Guam, Kiribati, Marshall Islands, Nauru, New Caledonia, New Zealand, Northern Marianas Islands, Nuie, Palau, Pitcairn Islands, Samoa, Solomon Islands, Tonga, Wallis and Futuna and Vanuatu.

IMPORTANT BIRD AREAS IN THE PACIFIC: A COMPENDIUM - Birdlife Pacific (2010)