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BIRDS OF THE REPUBLIC OF PANAMA PART 4 



in the tip of its bill, pulled them off, and then manipulated them back 

 into the mouth, where the berry was given a hard squeeze that crushed 

 it. When it was rolled forward again, the pit was discarded with a 

 scissorlike motion of the mandibles and the pericarp was swallowed. 

 All this was done rapidly and expertly. Other foods I have not myself 

 witnessed being taken are the eggs and young of other birds, and, not 

 uncommonly, adult birds as large as a Groove-billed Ani. A female 

 collected by Strauch (Bull. Brit. Orn. Club, 1977, p. 64) weighed 

 112.0 g. 



These are noisy birds with a wide repertoire of raucous calls: "both 

 sexes have a harsh chack; male gives a long strident whistle, weeek, 

 week, sometimes drawn out to weeeeek, and both sexes also give a rattl- 

 ing trit-trit-trit" (Ridgely, 1976, p. 309). It also has some more musi- 

 cal calls. The males, which are only half or a third as numerous as the 

 females, are aggressive about fighting among themselves and in court- 

 ing females. Males court by fluffing out the body plumage, shaking the 

 wings, and extending the bill and neck, while uttering a variety of calls. 

 Once I saw a male following a female in flight suddenly hold the wings 

 fully extended and flap them well below the line of his body for 8 or 10 

 strokes. 



I have seen females gathering nest material on January 21, 1961, at 

 Corozal in the Canal Zone and on February 16, 1944, at San Jose in 

 the Archipielago de las Perlas. Males that I collected on March 17, 

 1946, at Jaque, Darien, were only approaching breeding condition. On 

 Taboga Island, Panama, I saw females carrying food to young in the 

 nest on March 19, 1952, and on May 5, 1953, I saw grown young out 

 of the nest at Balboa, Canal Zone. Dorothy M. Hobson (Year Book 

 Indiana Audubon Soc, vol. 26, 1948, p. 24) saw young being fed in 

 Panama City on July 20, 1947. Evidently the nesting season varies in 

 date from locale to locale, and perhaps from year to year. 



Skutch (Pac. Coast Avif. no. 31, 1954, pp. 321-334) has studied this 

 species in Guatemala, where it nests in colonies that are often placed in 

 trees near water or in palms, as they are in Panama as well. However, 

 they may at times nest nearer the ground. Major General G. Ralph 

 Meyer found 3 nests on Taboguilla Island, Panama, on April 9, 1944, 

 that were in low bushes not over 1.3 m from the ground. The nest is 

 always a large, bulky cup made of grasses and other pliable plant fibers; 

 as in most other colonial icterids, there is much attempted stealing of 

 material from nearby nests, and I once saw a female simply take over 

 a mockingbird's nest under construction. A nest cup actually con- 



