Aquatic birds of the Americas
 K Kaufmann
A group of Western Sandpipers flying across Panama Bay IBA, a very important site for migratory and aquatic birds
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There are 532 aquatic bird species in the Americas. Some groups are of the highest conservation concern, an example being the rails Rallidae, with 14 threatened species in the Americas including various endangered nationally endemic species such as the Zapata Rail Cyanolimnas cerverai, restricted to the Zapata Swamp in Cuba, and the Plain-flanked Rail Rallus wetmorei, only found at a few sites on the Venezuelan coast.
Seabirds are another group that needs urgent conservation actions. Seabirds account for 53% of all globally threatened aquatic bird species in the Americas, highlighting the critical nature of threats at sea and to their breeding colonies. Of particular concern are albatrosses, such as the Waved Albatross Phoebastria irrorata that breeds on the Galapagos Islands, and the Chatham Albatross Thalassarche eremite that during their non-breeding season migrate to the coasts of Peru and Chile.
Other globally threatened species include the Junin Grebe Podiceps taczanowskii, a flightless waterbird confined to Lake Junín in the highlands of Peru, and the Brazilian Merganser Mergus octosetaceus restricted to fast-flowing crystal-clear rivers in central Brazil.
Shorebird populations are also in rapid decline, with the most infamous case being that of the Eskimo Curlew Numenius borealis, once a numerous species, but now considered possibly extinct as a result of hunting and habitat loss. Other populations, such as that of the rufa subspecies of Red Knot Calidris canutus have shown alarming declines, from 51,000 individuals in 2000 to 17,000 in 2006.
 Simon Stirrup
Waved Albatross, a Critical Endangered Species
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Threats
Aquatic birds are vulnerable to the loss and degradation of their habitats, whether resident species relying on a specific sites, or a long-distance migrants dependent on a network of wetlands. Among the most important threats are:
Fisheries: Of particular concern are the large numbers of pelagic-feeding seabirds that are incidentally caught and killed by longlines, gillnets, and other devices used in fisheries around the world (known as incidental catch or bycatch). However, fisheries also deplete the food resources that many pelagic and coastal species depend on.
Aquaculture: Poorly planned and regulated aquaculture of crayfish, shrimp, catfish, tropical aquarium fish, juvenile trout and salmon, baitfish, mussels, and oysters leads to habitat degradation, disruption of trophic systems and disease transmission.
Hunting: Sport or food hunting of waterbird species are legal activities in some countries of the Americas, and such human-induced mortality, legal or not, has great potential to depress populations.
Reduction in habitat quality: Aquatic habitats are subject to significant physical and chemical modifications from poorly planned water management, dredging, ditching, sedimentation, runoff, and introduction of invasive plant species - modifications that destroy or degrade habitat for waterbirds.
Climate Change: Changes in sea level and rainfall patterns will greatly affect habitat availability and ultimately the timing of nesting and migration.
 Lorenzo Calcaño/SCAV
One of the main problems for aquatic birds is habitat deterioration
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