288 



BIRDS OF THE REPUBLIC OF PANAMA PART 4 



from 13.2 to 16.0 g. A female taken at Fort Sherman, Canal Zone, by 

 G. V. N. Powell (in litt. to Eisenmann) weighed 18 g. 



SEIURUS MOTACILLA (Vieillot): Louisiana Waterthrush, 

 Reinita Arrollera de Louisiana 



Turdus motacilla Vieillot, 1808, Hist. Nat. Ois. Amer. Sept., 2 (1807), p. 9, p. 65. 

 (Kentucky.) 



Small; upper surface olive-brown; undersurface white, streaked 

 olive-brown across breast and sides. 



Description. — Length 129-141 mm. Adult (sexes alike), upper sur- 

 face, including wings and tail, line through eye, and side of face, olive- 

 brown; superciliary white, extending to nape; line around lower por- 

 tion of eye, moustachial stripe, and undersurface white, becoming buf fy 

 on abdomen and undertail coverts, and with olive-brown streaks on 

 breast and sides; underwing coverts buffy brown. 



Measurements. — Males (9 from Panama, Costa Rica, and Colom- 

 bia), wing 80.1-83.4 (82.2), tail 44.6-54.4 (50.4), culmen from base 

 14.4-16.9 (15.5), tarsus 21.5-22.7 (22.2) mm. 



Females (9 from Panama), wing 72.5-82.2 (77.5), tail 46.7-54.7 

 (50.0), culmen from base 14.2-16.4 (15.5, average of 8), tarsus 21.3- 

 23.1 (22.4) mm. 



Migrant and winter visitor from the north. Uncommon as a migrant, 

 chiefly in mid- August to September and in March, when it may be found 

 throughout the Republic, and rather rare as a winter resident, mostly 

 in highlands of Chiriqui. The Louisiana Waterthrush prefers running 

 water. The first to arrive in Panama appear by early August — long be- 

 fore any Northern Waterthrushes — and some linger into early April 

 (Ridgely, 1976, p. 298). Most have left Panama by mid-March; later 

 sight reports may be misidentified Northern Waterthrushes. The lat- 

 est known report from Panama is a specimen netted at Almirante, 

 Bocas del Toro, April 3, 1965 (D. L. Hicks, Univ. Georgia coll.). 

 Monniche (Blake, Fieldiana: Zool., vol. 36, no. 5, 1958, p. 559) col- 

 lected a female at 1650 m on the Volcan de Chiriqui. On the Pearl 

 Islands W. W. Brown, Jr., (Thayer and Bangs, Bull. Mus. Comp. 

 Zool., vol. 46, 1905, p. 156) collected 1 on San Miguel on March 18, 

 1904, and I saw 1 on San Jose on March 7, 1946. 



If the absence of fat can be taken as an indication that a bird is not 

 yet migrating, then individuals I collected at the Peluca Hydrographic 

 Station in the Province of Panama on February 21, 1961, and on the 

 south fork of the Rio Pucro on Cerro Mali, Darien, on March 2, 1964, 

 were winter residents. On Barro Colorado Island, Willis (Living Bird, 



