WILSON'S PILEOLATED WARBLER 633 



Winter. — Dr. Alexander F. Skutch (MS.) sends to A. C. Bent the 

 following comprehensive account of the bird as he has seen it during 

 the winter in Central America : "All three forms of Wilson's warbler 

 pass the winter months in Central America. Of these, the race that 

 breeds in the Rocky Mountains, the pileolated warbler, appears from 

 the determination of specimens to be far the most numerous. Yet 

 since all three may occur in the same locality and it is difficult or 

 impossible to distinguish them in the field, it seems best to treat them 

 all under the name of the typical form. 



"Arriving early in September in Guatemala, and about the middle 

 of the month in Costa Rica, Wilson's warblers rapidly increase in 

 numbers until they are among the most abundant of wintering 

 warblers. They settle down for their long sojourn in a great variety 

 of situations, from the warm lowlands up to the bushy summits of 

 the higher mountains that are so cold and frosty during the nights 

 of the northern winter. I have found them abundant even at 11,000 

 feet above sea level. They are far less common in the Caribbean 

 lowlands than they become above 1,500 feet, and are distinctly un- 

 common on the Pacific side of Central America below 2,000 feet. But 

 from these levels up to the tree line, there seems to be slight variation 

 in their midwinter abundance, which is associated with the type of 

 vegetation rather than with altitude. Everywhere the blackcaps 

 haunt the bushy abandoned fields, neglected pastures, openings in 

 the forest, hedgerows, and at times even the dooryard shrubbery. 

 They avoid the sunless undergrowth of heavy forests, yet frequent 

 the lighter woods of oak and pine in the highlands, and the thinner 

 of the woodlands at lower elevations. Restless and sprightly, they 

 flit tirelessly among the bushes in pursuit of tiny insects, constantly 

 advertising their presence with their emphatic nasal chip. 



"The period of absence of Wilson's warbler from Central America 

 is brief. On the Sierra de Tecpan in the Guatemalan highlands, I saw 

 the last one of the season on May 22, 1933. The first fall arrival was 

 encountered on September 3 of the same year ; four were seen on the 

 following day, and by the fifth of the month, they were so numerous 

 that it was hopeless to try to keep count of them. They had been absent 

 only 3 months and 12 days. At Vara Blanca on the Cordillera Central 

 of Costa Rica, the first appeared on September 18, 1937, and the last 

 was seen on May 5 of the following year. They were present through 

 the 5'ear, save for a period of 4 months and 13 days. 



"Although at times Wilson's warblers are present on the bushy 

 mountain slopes in such great numbers that they give the impression 

 of being gregarious, they are in fact evenly distributed through the 

 bushes. Where less abundant, they are seen singly rather than in 

 flocks, for they are intolerant of the company of their own kind during 



