Sf4 



NAUCLERUS FORFJCATUS. 



marshes of the Everglades, where it resides throughout the year, but it also occurs in all 

 the fresh water marshes of Middle and Southern Florida. 



GENUS III. NAUCLERCS. TllK I'ORK-XAILIOD KITES. 



Gen'. Cu. Bil/, short, well curved, wilh the cuitin<j eS<jr of upper mandible not lohed. Tarsus, not long and nearly nak- 

 ed. Tail, very deeply emaryinate , excecdiny in Icnytli one half the Icnyth of the wings which are considerably elonyated. 

 Thet'e is no ruff on the face. 



Membei-s of tliis genus have no ruJT. en- fiicial disk, nor are the ear cavities strikingly large. The leg is short and the 

 tarsus is naked to the heel behind, bat is sligluly feathered in front. Tlie claws are quite short but pointed. Only one 

 outer quill is noticeably incised on the inoer webs. 



The trachea is flattened throughout. The sterno-traehealis is short, having its origin about '25 from the larynx, and 

 there is a slender bronchialis extending overall the half rings, but there are no other laryngeal muscle;. Tlie tympaniform 

 membrane is present and although there is a thin os transversale, it dues not support a semilunar meml)rane. The walls 

 of tlie oesophagus are thin; this is at fii-st nearly straight, but Is not dilated into a crop, thus forming a striking exception to 

 the rule among birds of this order. It 0|)cns into a rather small proventriculus with simple, oval glands arranged in a zon- 

 ular band which measures 1-00 \-nforficatus, from wliicli this and the following dimensions were taken. The stomach is 

 of a large size, somewhat globular in form, with thin but soft walls , and is lined with a soft membrane. The fold of the 

 duodenum is long, measuring .3'00, inclosing a narrow pancreas which extends it-i entire length. There are no traces 

 whatever of any cceoa on either side cf the intestine. The spleen is an elliptical body lying directly on the proventriculus. 

 Both lobes of the liver are short and thick, but the left is larger than the right. The heart is large and not very pointed. 

 Sexes, similar in color. There is but one species within our limits. 



NAUCLERUS FORFICATUS. 



Swallow-tailed Kite. 



Nauclerus forficatus Ridgw., B. B. R., N. A. Birds, III; 1874, 192. 



DESCRIPTION. 



Sp. Cn. Form, rather slender. Size, medium. Sternum, rather stout, with the marginal indentations varying with 

 age. Tongue, short, not very Uesh.y, and about the same width for nearly its entire length, then gradually rounded and bi- 

 fid. Bill, rather short. Feet, coraiiarativcly weak, with short claws. Tail, very deeply forked, the outer being nearly 

 twice the length of the middle. 



CoLon. Adult. Head and n:-;ok all around, under portions, including under wing coverts, under tail coverts, and tib- 

 ia, middle of back, basal portion of a large part of tertiaries and of asmall part of secondaries, white, with the shafts of the 

 feathers on the head, neck, and breast, black. Remainder of upper portiun:^, including wings, upper tail coverts, and tail, 

 black, glossed with green. 



Young. Similar to the adult but somewhat less green on *he black above which is also a little duller, and the tail is 

 not as long. 



Nestlings. Are at first covered witli a yellowish down, then gradually assume theiJumage last described. Bill, black, 

 cere, green, eyes, dark-brown, feet, light-blue, in all stages. 



OBSERVATIONS. 



There appears to he but little variation in specimens of the .same age. Known from all other species which occur with- 

 in our liuiits by the long, very deeply forked tail and by the colors as described. Distributed, as a summer resident, 

 throughout the Southern States, north to Virginia. Rare in the Middle States and accidental in Western Massachusetts. 

 Wintei-s in Central and South America. 



DIMENSIONS. 



Average measurements of male specimens from Southern United States. Length, 22-00; stretch, 46'00; wing, 15-00; tail, 

 12-50: bill, 100; tai-sus, MO. Limgest specimen, 23-00; greatest extent of wing, 47-00; longest wing, 16-00; tail, 13 00; 

 bill, 1 25; tarsus, 1 20. Shortest specimen, 21-00; smallest extent of wing, 45-00; shortest wing, 14-00; tail, 12 00; bill, MO; 

 tarsus, 1-15. 



Aver.agc measurements of f^iinalesp^cimsns from Soutliern United S'.ates. Length, 24'50; stretch, 51-00; wing, lO'OO 

 tail, l3-()0; bill, TOO; f.irsus, I'lo. Longest specimen, £5-50; greatest extent i f wing, 51-50; Imgestwing, 17-(I0; tail, 140<) 

 bill, 1 25; tarsus, r35. Shortest spjciiajn, 23-50; smallest extent of wing, 50-00, shortest wing, 15-00; tail, 12-00; bill, TIO 

 tarsus, 1-20. 



