Designed by Paul Smith 2006. This website is copyrighted by law.
Material contained herewith may not be used without the prior written permission of FAUNA Paraguay.
Photographs on this web-site were taken by Paul Smith, Hemme Batjes, Regis Nossent,
Alberto Esquivel, Arne Lesterhuis, José Luis Cartes, Rebecca Zarza and Hugo del Castillo and are used with their permission.
SCOLOPACIDAE - WADERS
Twenty-two species in Paraguay which can be classified into two subfamilies and 6 tribes. The stereotypical Scolopacid is a long-necked, long-legged wading bird with a long, highly-specialised bill. The bill is rhynchokinetic, in other words it is flexible at the tip and is generally used in probing for food. The tibia is bare and the toes are long, with a short hallux present in all but one species. The tarsus is scutellated on the front and usually also behind. In most cases the wings are long and pointed and the tail short. Most flock and all are strong fliers, often performing impressive group aerobatics. The majority of species are Nearctic migrants and undergo considerable plumage changes between the breeding grounds and wintering grounds which can complicate identification.
Subfamily Scolopacinae "Sandpipers and Allies"
Twenty Paraguayan species in nine genera. Classification at subfamilial level in this family is the subject of much debate and a genetic study is needed to better define the relationships between the species. The classification used here is that of the AOU Checklist 7th edition, supplement 47 which places the Paraguayan species into six tribes. Because of the great variation in body forms, the characteristics are detailed under each tribe.
Tringini "Shanks" (Actitis, Tringa) - Long-necked, long-legged, long-tailed, long-billed sandpipers with slender and graceful form. Bill with hardened tip, adapted for picking feeding motion. Hallux well-developed and tarsi frequently brightly-coloured. Wings long and pointed. Webbing of toes limited to small web between outer and middle toe. Tarsus not compressed, scutellated on the front and usually behind.
Numeniini "Curlews" (Bartramia, Numenius) - Large, long-necked, long-legged, long-tailed, long-billed sandpipers. Curlews with downcurved bill longer than tarsus, tarsus scutellated on the front and reticulated behind and well-developed hind toe. Essentially brown and undergoes no plumage change. Bartramia with shorter, straight bill approximately half tarsus length, thin neck and "pea-headed" jizz. Tarsus scutellated on both sides. Small web between outer and middle toes and well-developed hallux. Bartramia appears to be intermediate between curlews and shanks, but is usually placed here.
Limosini "Godwits" (Limosa) - Large, graceful, slender waders. Long-necked, long-legged, long-tailed and long-billed. Bill slightly recurved. Tarsus scutellated on both sides. Hallux well-developed and distinct webs between outer and middle toe. Pectinated inner edge of middle claw. Conspicuous black-and-white wing pattern. Female clearly larger than male.
Arenariini "Turnstones" (Arenaria) - Dumpy and plover-like with short neck and stocky body. Bill short, blunt and wedge-like, used for over-turning stones when foraging facilitated by powerful neck muscles. Flies strongly on pointed wings with eyecatching black-and-white wing pattern. Short hallux. Short tarsus scutellated on both sides. No webbing between toes. Long, slightly rounded tail. Rarely found far from the coast, just a single record from Paraguay.
Calidrini "Peeps" (Calidris, Tryngites) - Small to medium-sized typical sandpipers, providing a considerable identification challenge in winter plumage. Collective name of "peeps" refers to their flight vocalisations. Bill pointed with flexible tips armed with sensory cells to detect vibrations made by prey. Nostrils set in a groove extending almost to the tip of the bill. Tarsus scutellated on both sides. Long, thin, pointed wings usually with white central band in Calidris. Hallux short (absent in Calidris alba). Unwebbed toes (with the exception of Calidris pusilla). Tail square in Calidris, central feathers longer and more pointed than others. Tryngites with more rounded tail of 12 retrices.
Gallinagini "Snipe" (Gallinago) - Distinctive, cryptically-coloured waders with exceptionally long, straight bill and short legs. Bill much longer than tarsus and with soft, flexible tip. Tarsus scutellated on both sides, well-developed but small hallux. Front toes unwebbed. Banded head pattern. Eyes set high on the head and enclosed in bony orbit, ear opening located anterior to the eye. Posterior skull conical. Sewing machine probing feeding technique. Crouches motionless when disturbed, erupting suddenly into flight when approached. Produce mechanical sounds with outer tail feathers during display - known as "winnowing".
Subfamily Phalaropinae "Phalaropes"
Two species in the genus Phalaropus recorded in Paraguay, one of which occurs regularly. This group is of uncertain affinities and has in the past been classified in its own family the Phalaropidae. Certainly they are atypical waders, adapted for a more aquatic existence. Typically they have long legs, scutellated front and back, and long, weak, needle-like bills. The dense breast plumage provides a raft of air upon which they float, whilst the laterally compressed legs set normally on the body (not further back like a duck) undoubtedly aid in the unique "spinning" feeding technique which they adopt. All four toes are fringed with convex scales and there are short webs between the forward facing toes. Sexual roles are reversed, females being larger and more brightly-coloured. Moult takes place soon after leaving the northern hemisphere breeding sites.
REFERENCES
Campbell B & Lack E 1985 - A Dictionary of Birds - T & AD Poyser.
Hayman P, Marchant J & Prater T 1986 - Shorebirds: An Identification Guide to the Waders of the World - Helm.
Johnsgard PA 1981 - The Plovers, Sandpipers and Snipes of the World - Nebraska University Press.
