FAMILY FREGATIDAE 75 



In June 1953 scores of frigates, most of them immature, ranged 

 over the open water at the head of Montijo Bay. As the tide rose 

 the birds followed up the Rio San Pablo for some distance. Twice I 

 saw one pick up a sea snake swimming at the surface and carry it, 

 as it twisted and coiled, for a short distance with other frigates in 

 close pursuit, and then finally let it drop. Frank Violette, of long ex- 

 perience in fishing the waters of the Gulf, has told me that when the 

 frigatebird sees large billfish — marlin and sailfish — it watches them 

 as it turns in small circles high in air. He has located such fish 

 frequently by observing this maneuver. 



At the end of February 1957 I estimated that a thousand pairs 

 were nesting on Isla Iguana, north of Punta Mala. The birds here 

 occupied most of the island except for a small clearing where two 

 houses were located. Only the pelicans were able to compete with 

 them for nesting sites. Chattering calls came constantly from the 

 birds on their nests. Males had the balloonlike, red throat pouches 

 inflated, and often flew about with bits of grass dangling from the 

 bill. 



On February 28 I found between 75 and 100 pairs at Isla Villa 

 and 30 or so at Farallon del Chiru. 



Hundreds roost on the steep western slopes of Isla Taboga, but 

 during my visits at various times from December to March I have 

 not noted nests. I believed that the frigatebirds seen around Isla 

 Pelado off the mouth of Rio Chiman in February and March 1950 

 may have nested there, but of this I was not certain. Formerly they 

 were located on the "Fortified Islands" at the Pacific entrance of the 

 Canal. 



At Isla Chame near Taboga, on February 15, 1942, Maj. Gen. 

 G. Ralph Meyer collected several eggs, ranging from fresh to three- 

 fifths incubated. The nests were shallow platforms of twigs 300 to 

 400 mm. in diameter, lined scantily with finer materials, placed 3 me- 

 ters or so above the ground in the low trees that form groves on the 

 steep slopes of the island, often closely grouped with several in one 

 tree. On a previous visit on February 23, 1941, he had found that 

 several eggs were nearly ready to hatch. On Isla Iguana many of the 

 nests were only 1^ meters or so above the ground, and regularly I 

 walked underneath those higher while the birds watched me within a 

 few meters of my head. 



One egg is laid in each nest, its color chalky white, with a slightly 

 roughened shell — sometimes stained with streaks of brown, apparently 

 from blood during laying. In shape they vary considerably from 



