FAMILY CHARADRIIDAE 389 



The species is one that I have known in other regions, but one 

 that I sought over many miles of beach, mudflat, and stream edge 

 for ten years before I found my first individual on the isthmus. On 

 March 26, 1957, above the head of tidewater on the Rio Tonosi in 

 Los Santos, mangrove swallows and black jaqanas drew me to a 

 broad gravel bar in the river bed. Here, presently, two small 

 plovers that at a casual glance I supposed would be the semipalmated 

 rose, but in the same instant it was obvious that they were a lighter, 

 browner gray, and as they alighted I saw that they were my long- 

 sought collared plover. Both were males. 



At Changuinola, Bocas del Toro, in January 1958, a few of this 

 species ranged with other shore birds on the golf course after rains. 

 On January 30 I counted six in company. I found others on the outer 

 beach along Tirbi Bight, above Boca del Drago, on February 20, 

 where I believed they were on their breeding grounds, as a male 

 taken here had the testes beginning to enlarge. Apparently they are 

 more common in this area than elsewhere, as Eisenmann (Condor, 

 1957, p. 252) found 2 pairs at the mouth of the Rio San San, farther 

 along on this same stretch of shore. 



The flight of these plovers is direct, fairly rapid, and low over 

 open ground or water. Usually after alighting they teeter once or 

 twice, but then walk about slowly, seeming rather inactive. But also 

 they may run quickly with the head down, and then stop suddenly 

 with the head erect but the neck still shortened. In general actions 

 they resemble the snowy plover, but seldom run as far without 

 stopping. On the outer beaches when approached they move back 

 above the crown, where they are inconspicuous among the scattered 

 bits of drift. 



The alarm note is a sharp metallic tsee. Another common note 

 is a slightly rolling tur-r-r. These notes are heard most often during 

 the breeding season. At other periods usually they are silent. 



A set of 2 eggs in the U. S. National Museum was collected on 

 September 30, 1926, by E. G. Holt, on the Rio Araguaya, below 

 Macauba, Goias, Brazil. The shell is smooth, without gloss, with the 

 ground color slightly paler than pinkish buff. Small, irregular black 

 spots are scattered over the surface, somewhat less abundantly near 

 the small end. The measurements are 28.3 X 20.9 and 28.4 x 21 .2 mm. 

 Schonwetter (Handb. Ool., pt. 7, 1963, p. 387) lists the variation in 

 size found in 36 eggs as 26-31x19.1-22.5 mm. 



