FAMILY COEREBIDAE 



507 



hook of the premaxilla grasps the flower securely. The tongue is elon- 

 gate, slender, and split for its entire length. The birds forage singly or 

 in pairs, moving rapidly through their small territories and examining 

 the same bushes repeatedly for fresh flowers. While flower-piercers 

 always reach flowers from a perch, their insect food is usually taken in 

 the air on short fly-catching sorties. On October 1, 1965, below Cerro 

 Punta, Eisenmann (in litt.) saw 1 feeding at the scarlet flowers of an 

 Erythrina tree; it was chased away by a Violet Sabrewing (Campy- 

 lopterus hemileucurus) . 



Eisenmann reports a male singing at Cerro Punta, Chiriqui, on Feb- 

 ruary 28, 1960, from a blackberry (Rubus) vine 2 m from the ground. 

 The song was a fast, thin, squeaky, high twitter lasting about 2 seconds, 

 and then repeated after a pause: zweezee, zweezee, tzeedeea, dzeedzee. 

 Other vocalizations include a "plaintive, high-pitched chee chee chee 

 chee chee chee" (Skutch, Pacific Coast Avif. no. 31, 1954, p. 426), and 

 a tsip note. Flower-piercers sing throughout their long breeding season. 



Skutch (op. cit.) has studied the breeding biology of this race in 

 Costa Rica, where the nesting season is tied to the abundance of nectar 

 resources; he found flower-piercers nesting all through the year except 

 in April, May, and June. A male that I took at Cerro Punta on Febru- 

 ary 28, 1955, was in near breeding condition, so perhaps the season 

 here is different. I have no further information from Panama. Skutch 

 found that the nest is built entirely by the female. It is placed off the 

 ground in tussocks of tall pasture grass or in a tree, as high as 3 m from 

 the ground. The nest is a bulky, open cup made of moss, vegetable 

 fibers, decaying leaves, and bits of papery bark; the lining is of finer 

 fibers. 



The clutch consists of two eggs that are light blue, finely speckled 

 with brown. Four eggs varied from 16.7 to 17.5 mm in length and all 

 were 12.7 in diameter. At one nest the incubation period was 14 days. 

 The young, born blind and with a thin covering of down, are fed by 

 both parents, who regurgitated to the nestlings what Skutch believed 

 was mainly insect matter. At 1 1 days the young are fully feathered and 

 at 13 days can fly just enough to leave the nest if it is disturbed; the 

 usual departure time is probably at 16 days. 



In western Chiriqui, Eisenmann has noticed occasional albinistic in- 

 dividuals with small white patches on the head; once (with N. G. 

 Smith) he saw 1 that seemed entirely white except for a tinge of buff 

 and black on the wings and tail. 



Of 2 collected by Strauch (Bull. Brit. Orn. Club, 1977, p. 64) at 

 Cerro Punta, a male weighed 9.3 and a female weighed 9.8 g. 



