68 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 56 



Others fly in to join these ranks there is often a chorus of the 

 croaking, grunting calls that are the only notes of these birds. 



In addition to these flocks, scattered birds are found everywhere 

 along the coasts and inland wherever there is suitable water. While 

 these birds may feed alone, usually they gather in little groups to 

 rest and to sleep — on the coast on trees or rocks along the shore, 

 and inland in dead trees or branches bare of leaves over, or beside, 

 the water. As a boat approaches, these resting birds begin to twist 

 about, until finally they pitch awkwardly into the air where their 

 wings beat heavily to gain momentum for flight, or they plunge 

 beneath the water to appear at a safe distance many meters away. 



On the larger rivers as the Tuira and the Chucunaque cormorants 

 are found in hundreds, most of them above the limit of tide. Con- 

 stantly shifting currents below that point usually keep the streams 

 muddy, so that fish if not actually more abundant are more easily 

 obtained in the clearer waters above. Practically all these cormorants 

 are immature individuals, some in first, and others in second-year 

 plumage, to judge from their color. It is my supposition that many 

 of the young birds from the nesting colonies in the Gulf move to 

 such fresh waters and remain there more or less permanently until 

 ready to breed. One indication of this is that on the upper courses 

 of uninhabited streams young cormorants are often almost stupidly 

 tame, presumably through lack of experience in dangers that would 

 be theirs during more extensive journeys. 



On the other hand, it is quite probable that part of the cormorants 

 in these same stages of plumage, found in Bocas del Toro, and 

 elsewhere in western Panama may be migrants from elsewhere in 

 the Tropics. In crossing from Bocas del Toro to Panama in a Cessna 

 plane on one occasion I saw one cormorant flying at an elevation of 

 350 meters across the extensive area of unbroken forest of this part 

 of the Caribbean slope, an indication of wandering that would bring 

 these birds into the remote and isolated waters where they are some- 

 times found. 



The abundance of this species in Panama attracted the attention 

 of early travelers, even of the buccaneers, as they are one of the 

 birds described in some detail by Lionel Wafer in his account of 

 Darien (Isthm. Amer., 1699, p. 121). 



The nesting season appears to come in April, as W. W. Brown, 

 Jr., noted a nest with 6 incubated eggs April 14, 1904, on Isla Saboga 

 (Thayer and Bangs, Bull. Mus. Comp. ZooL, vol. 46, 1905, p. 141). 

 On April 24, 1949, in early morning as I watched flocks of cormorants 



