FAMILY ARDEIDAE 87 



Measurements. — Males (20 specimens from Panama), wing 162- 

 173 (168), tail 55.0-64.5 (59.0), culmen from base 53.3-66.2 (60.6), 

 tarsus 44.0-51.6 (48.4) mm. 



Females (9 specimens from Panama), wing 157-169 (161), tail 

 51.8-59.7 (56.4), culmen from base 57.1-62.8 (59.5), tarsus 44.7-50.0 

 (47.7) mm. 



Resident. Common throughout Darien, ranging west to the eastern 

 side of the Azuero Peninsula, and to western Col6n. One record for 

 Puerto Obaldia, San Bias. 



Typical gray-necked adult specimens come from near Yavisa on 

 the lower Rio Chucunaque, mouth of the Rio Paya on the middle 

 Tuira, and Jaque; also one from Chilar on the Rio Indio, western 

 Colon. I have sight records for the Rio Chucunaque, from the mouth 

 of the river upstream to the Rio Ucurganti; on the Rio Pequeni 

 above Madden Lake ; in the marshes at La Jagua, in eastern Panama 

 Province ; and at Juan Mina, Canal Zone, on the Rio Chagres. 



While the only record for the Comarca de San Bias is an imma- 

 ture female in the Brandt collection at the University of Cincinnati, 

 taken by Wedel at Puerto Obaldia, July 3, 1932, there is no reason to 

 suppose that it does not occur in that area regularly, as it is found at 

 Acandi, Choco, immediately adjacent on the Colombian side of the 

 boundary. 



The many records available for the patens style of coloration in 

 which the side of the head and neck are buff, include the following: 

 Several from the Province of Herrera on the eastern side of the 

 Azuero Peninsula; one from Guanico Arriba in southwestern Los 

 Santos; Chilar, western Col6n; Barro Colorado Island, and Juan 

 Mina, Canal Zone ; La Jagua Hunting Club near Chico and Charco del 

 Toro, eastern Province of Panama ; and Jaque and the Rio Jaque, 

 Darien. 



In work on Barro Colorado Island, Van Tyne (Occ. Pap. Mus. 

 Zool. Michigan, no. 525, 1950, pp. 5-6) noted that the breeding sea- 

 son may be either somewhat irregular or of long duration. A male 

 collected on March 7, 1926, had completed the breeding cycle and 

 was in postnuptial molt. Another shot April 11, 1927, was breeding, 

 and a nest with 2 eggs was found July 28, 1925. On August 1 1 two 

 partly grown young were taken from another nest. The nest with 

 eggs was located "on an isolated stump off the south shore of the 

 island." Other nests on Barro Colorado on March 24 with 3 eggs, 

 and April 28, 1935, with 2 eggs, are recorded by Chapman (Life in 



