Habitats and sub-habitats found in the aquatic environment:-
1. Marine.
Oceans eg Atlantic, Pacific, Indian, Arctic, Southern, Tropical, Antarctic.
Seas eg North, Mediterranean etc.
Coastal eg Mainland or Island.
2. Inland Waters.
Can be saline, brackish or fresh. Sub-habitats may relate to emergent vegetation either in or at the margins of the water bodies:-
- Lakes, Lagoons, Reservoirs.
- Rivers and Streams.
- Marshland with reed-beds.
- Swampland – deeper water than marshland eg. Mangrove swamps.
Examples of the birds concerned and percetages of the world's species are:-
1. Oceans and seas 2.9%
These large bodied birds fly and or swim to avoid predators. Potential foods are fish, aquatic organisms, plant materials and insects. In addition to being aquatic their habitats are mainly defined by the way in which the birds catch their food:-
- Plunge divers - Pelican, Tropicbird, Gannet, Booby.
- Swim pursuers - Penguin, Auk, Murre, Guillemot, Razorbill, Puffin.
- Surface feeders, scavengers - Albatross, Petrels, Shearwater, Gulls.
- Surface feeders, piratical - Frigatebird, Skua, Jaeger.
- Hover then dive - Tern.
- Surface skimmers - Skimmers.
- Surface feeders, spinners - Phalaropes.
2. Inland water bodies 2.3%.
Some birds found mainly on inland water bodies behave in a similar way to the ocean and sea birds above.
- Dive and catch with talons - Osprey, Fish Eagles.
- Dive & swim to pursue - Loon, Grebe, Cormorants, Anhinga, Coot, Merganser, Smew, Goldeneye.
Another sub-group of birds, found mainly on inland waters and surrounding grasslands, are the Waterfowl:-
- Grass & water, graze/forage - Screamer, Magpie Goose, Whistling Duck, Shelduck, Goose, Swan, Duck.
3. Coastal and inland water shores 1.7%
Mainly large to medium sized birds, water and flight provide means to escape danger. Some birds feed together in the same habitat by probing at different depths for aquatic invertebrates:-
- Shallow open water / probers- Flamingo, Spoonbill, Jacana, Avocet, Stilt, Painted Snipe.
- Coastal and inland / probers - Godwit, Shanks, Sandpipers, Dunlin.
- Shore & moorland / surface pluckers - Plovers, Lapwings, Oyster Catchers, Crab Plover.
- Coastal areas / opportunistic scavengers - Sheathbills.
4. Open grassland and wetland 1.3%.
This habitat is favoured by large, confident, ground foraging birds:-
- Grassland and wetland / graze & forage - Crane, Limpkin, Stork, Ibis.
- Wetland / spear, dagger beak - Heron, Egret, Bittern. Hamerkop, Shoebill.
Notes. 1. Cranes adapt well to various habitats. 2. Limpkin only N & C. America. 3. Hamerkop and Shoebill are aberrant birds.
5. Rivers and Streams 0.4%
Rivers and streams are often bordered by vegetation and trees which provide a safe refuge for birds in this habitat:-
- River birds / perch & dive / dagger beak – Kingfishers.
- River birds / forage under water - Dippers.
- Forage banks of streams – Sunbittern, Ibis bill.
Notes. 1. Some Kingfishers don't eat fish and are not found near water - see Kookaburras. 2. Ibis bill – only in Europe.
6. Reed-beds, marshlands, swamps 1.6%.
In addition to food this habitat provides camouflage and an escape route:-
- Marsh and pond grazers - Moorhen, Swamphen.
- Wetland, swamp & marshland / probers - Snipe, Jacksnipe, Flufftails, Rail, Crakes, Finfoot, Sungrebe.
- Reed stem gleaners Bearded Reedling in Europe. NW. Blackbirds in Americas.
- Undergrowth, dense waterside vegetation – Coucals.
Notes. 1. Fufftails are only found in Africa. 2. Finfoots are found in Africa and Asia 3. Sungrebe is found in C. America. 4. Coucals or Cuckoo-Rollers are birds of Australasia and Africa. Other birds are found in all regions.