FAMILY ARDEIDAE 89 



Resident in part, and in part a winter visitor from the north. Com- 

 mon along the coasts, and, in the lowlands, inland along open bodies 

 of water ; ranging to the smallest offshore islands. 



There are records of two banded in Mississippi, one taken near 

 Sona, and the other near Puerto Aguadulce. 



In the Archipielago de las Perlas these herons are common along 

 the shores, where their white plumage stands out in pleasing contrast 

 to the dark rocks on which they rest. They make long flights reg- 

 ularly over the open sea. Robins (Condor, 1958, p. 302) reported 

 one 18 miles south of Taboga, apparently crossing from the Perlas 

 group, and Murphy (Vert. SCOPE, 1956, p. 135) records one on 

 an evidently longer journey 90 miles south of Punta Mala. 



In Panama, as elsewhere, this egret was more abundant in early 

 days, as Rendahl (Ark. Zool., Bd. 12, 1919, p. 6; idem, Bd. 13,1920, 

 p. 13) recorded great flocks seen in 1882 by Dr. C. Bovallius near the 

 Rio Pacora, on Isla Chepillo, and on Isla Bayoneta. They are still 

 common, as flocks of two hundred or more may congregate on open 

 lagoons, though it is more usual to see single birds, or two or three 

 in company. In wet pasture lands they are seen regularly around 

 cattle. 



Though these herons evidently nest in scattered groups along the 

 coasts, the only colony of record is one on Isla Changame, off Batele 

 Point west of the Pacific entrance of the Panama Canal. Here on 

 February 15, 1941, Maj. Gen. G. Ralph Meyer found several nests 

 located about 2 meters from the ground, in stands of mangroves and 

 clumps of cactus. The herons had constructed platforms of weed 

 stems 300 to 350 mm. in diameter, loosely placed in the usual style 

 of this family of birds, with a slight depression to hold the eggs. 

 Incubation had begun in two sets of 3 eggs each. He took another 

 set of 2 eggs, with incubation begun, here on February 23, 1941, and 

 on February 15, 1942, one set of 2 eggs, and two of 3 each, with incu- 

 bation well started. These eggs vary from subelliptical to long ellipti- 

 cal in form, and from Court gray to slightly paler in color. The 

 range of measurement in 11 eggs (4 sets) collected on Changame is 

 as follows: Length 52.4 to 56.8; breadth 37.1 to 40.0; with an 

 average of 54.6 X 38.9 mm. 



EGRETTA THULA THULA (Molina): Snowy Egret; Garceta Blanca 

 Ardea Thula Molina, Sagg. Stor. Nat. Cliili, 1782, p. 235. (Chile.) 



This species and the little blue heron in white plumage are similar 

 in size and general appearance, but may be identified in life by dif- 

 ferences listed in color of the bill, tarsi and feet. 



