© Howard Martenstyn

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Terns, Gulls & Herons, Dutch Bay

Neritic & Pelagic Seabirds & Other Marine Related Birds

Neritic & Pelagic Seabirds

 

The term ‘seabird’ is somewhat inexact. It includes pelagic birds, which roam far out to sea and rarely sight land (they rarely come to land except to breed), coastal or neritic birds such as gulls (Laridae) and most terns, (Sternidae) that make their living in near-offshore waters, returning to land to roost and some will nest, and a few species which spend part of the year over land, altogether away from the sea.

 

At least fifty-three species of seabirds are currently recognised from Sri Lanka and almost all are migratory with a few breeding species. Some are famous for the great length of their long annual journeys. Several migratory species found around Sri Lanka are from September to April while some frigatebirds, petrels, shearwaters, skuas and noddies from the southern hemisphere are seen between March and October. The most intensive movement of seabirds occurs annually around July on the western seaboard.

Neritic and pelagic seabird distributions are tabulated in these two downloads. Probability distributions are provided based on studies to date and are provided for each species by maritime province and month.

Why Protect Seabirds

  1. Presence and numbers of seabirds are indicative of a healthy ocean. Seabirds control animal populations and ensure diversity, and therefore any forced reduction could cause an ecological imbalance.

  2. Seabirds have the potential to attract tourists each year amounting to foreign earnings.

  3. Sri Lanka should join and support international conservation and protection of seabirds because they traverse geographic and international boundaries and interbreed during their lifespan.

  4. Besides dolphins, seabirds too are the fishermen's best friend in guiding them to predatory fish feeding on baitfish.

  5. Seabirds are known to have led lost vessels to navigate to land.

 

Despite an increased interest in seabirds in recent years, Sri Lanka’s marine avifauna continues to be under-observed.

– Rex I. De Silva

Biologist, 2011

Threats
  • Poaching of eggs and sometimes even the birds.

  • Entanglement in fishing nets and foul-hooked on trolling lines.

  • Habitat destruction due to human development of nesting areas such as beach-front construction, land "reclamation" and increased tourism.

  • Pollution: Chemical pollution may create tumors; effluent from harbours near nesting sites may create disturbances.

  • Nest and hatchling predation on land by ants, feral dogs, jackals, mongoose, water monitors, crabs and raptors. Raptors and crows attack hatchlings.

 
Seabird Watching

 

Seabird watching is not only for ornithologists and recreational birders but also for those who may be interested in getting more out of a trip to the beach or out to sea. Land-based and sea-based watching have their advantages and disadvantages related to when observations can be made, approachability and line of sight. A good pair of binoculars and field guide is essential to get the most out of your expedition.

Locating seabirds is a matter of knowing where they are most likely to be at any given time. Seabirds do not wonder at random; their movements are governed by the fierce logic of survival and reproduction. A sound knowledge between seabirds and their preference for environments that are governed by oceanic conditions, their foraging and feeding behaviour, their seasonal appearance in different habitats and at points along migratory routes can substantially increase the probability of finding what you are looking for.

Recommended Field Guides:

  • A Field Guide to the Birds of Sri Lanka By John Harrison.

  • Birds of Sri Lanka by Deepal Warakagoda et al.

 

Further reading:

How to Watch - Where possible:

  • Use binoculars or a telescope.

  • Use bird hides or observe from a vehicle or boat.

  • Approach birds slowly, and adopt a prone position whilst observing.

  • Understand the birds’ situation, behaviour and recognise signs of stress. Back off if needed.

Approach without causing significant disturbance

How close you approach depends on the species, circumstances and how tolerant the birds are to humans. Reduce speed to less than 6 knots. If you frighten seabirds away or the bait fish on which they are feeding, then they may not get a similar chance for some time. Birds offshore, whether alone or in flocks may also be threatened as in addition to feeding they may be engaged in rest, preening, courtship or moulting.

 

Avoid any disturbance at breeding grounds

Normally keep 50-150m and up to 300m from very sensitive species. The effects of disturbance at the time of courtship can be particularly severe, disrupting the whole breeding cycle. Some seabirds, such as nesting terns, are very sensitive and disturbance may make them abandon a nesting site altogether.

Signs of stress and disturbance

Birds at sea will usually paddle gently away from an approaching boat. If you get uncomfortably close, birds will begin to paddle more rapidly, typically turning their heads from side to side to keep you in view before finally taking off. If you are a bird watcher and this happens, clearly you have been too close!

Birds on land typically take off as you approach and usually settle again behind you as you pass. Some birds make a loud alarm call and may circle a nesting site calling repeatedly or become aggressive, diving at anyone considered to be too close. Others may remain where they are in an attempt to draw you away from the nest by pretending to be injured, the so called “broken wing” display. If this happens, you are obviously too close to a nest. Some birds will lie low and freeze until the last possible moment, offering little warning of disturbance and reinforcing the need for vigilance.

Hotspots

 

Jaffna peninsular: Several areas. Palk Straight - terns and gulls, and migrating birds in September and April. Kayts causeway and surroundings - neritic seabirds.

Talaimannar: Adam's Bridge Isands - neritic and pelagic seabirds.

Mannar: Vankalai - Neritic seabirds.

Kalpitiya: West of Bar Reef Marine Sanctuary - flocks of terns, shearwaters and other pelagic seabirds. Dutch Bay estuary - large flocks of terns and gulls from October to April.

Chilaw: Sand spits located next to estuary mouth. Terns and gulls. Main sand spit accessed by short boat ride across river.

Amabalangoda: Rocky Islets Sanctuary aka Gendawana Gala located 450 m from the shore. Breeding colony of tern (muhudu-lihiniya in sinhala) species including greater crested terns. From mid-March to August. At risk due to fisheries activities. Access by boat via fisheries harbour.

Chundikulum Sanctuary: Neritic seabirds.

Nomenclature used for status of seabirds in Sri Lanka:

B: Breeding non-resident, R: Resident, CR: Common resident, RR: Rare resident, CM: Common migrant, U: Unconfirmed or uncertain, UM: Uncommon migrant, RM: Rare migrant, RRM: Rare but regular migrant, RIM: Rare and irregular migrant (vagrant), VRIM: Very rare and irregular migrant (vagrant)

Neritic Seabird Species
Pelagic Seabird Species
 
Marine Related Birds

 

Other birds too which are not classified as seabirds are found along or near Sri Lanka’s extensive coastline including estuaries and lagoons.

 

For example: 

  • White-bellied sea eagles, Haliaeetus leucogaster, and Brahminy Kites, Haliaster indus, are regularly seen gliding over coastlines.

  • Terrestrial birds can be seen travelling at sea or along the coastline during their migration.

  • Waders can be seen in lagoons such as Vankalai and Vidattaltivu lagoon, at Mannar during their migration.

  • Spot-billed pelicans, Pelecanus philippensis, are regularly seen in lagoons and estuaries.

  • The Blue Rock Pigeon, ගල් පරවියාColumba liviaa intermedia, a native endangered bird lives within the rocks on the near shore Pigeon Island National Park, Nilaveli.

  • Greater flamingoes are best seen in Vankalai Sanctuary, Mannar in February.

Dolphin-Seabird-Baitfish Association

© Howard Martenstyn