420 BULLETIN 20 3, UNITED STATES NATIONAL MUSEUM 



egg. The male brings food for the female at intervals, and she com- 

 monly leaves the nest at his approach, meeting him in a nearby pine 

 and fluttering her wings like a young bird. As incubation progresses, 

 the male sometimes comes to the nest to feed his mate. When flushed 

 from the nest, the female usually flutters along the ground in an 

 "injury feigning" display. Incubation routine seems to consist of 

 10- to 15-minute periods of absence from the nest, alternating with 

 periods of an hour or more on the nest (extremes: absent, 4 to 23 

 minutes ; on the nest, 48 to 112 minutes) . 



Eggs. — There are usually four or five eggs in a set. Most nests 

 reported with 3-egg sets probably contain incomplete clutches or have 

 been raided by cowbirds ; many such nests contain one to three cow- 

 bird eggs. The eggs of Kirtland's warbler are ovate to short ovate 

 and are rather variable in color and pattern. They are creamy white 

 or slightly pinkish white, speckled and blotched with "fawn color" 

 and "wood brown." Occasionally the markings are rather uniformly 

 distributed over the whole surface, but usually there is a concentration 

 of markings in a wreath or cap about the larger end. In spite of this 

 great range in markings, cowbird eggs can be distinguished from them 

 by their larger size, more bluish ground color, and the fact that the 

 two ends are marked alike. The eggs of Kirtland's warbler usually 

 measure about 18.5 by 14 millimeters ; extremes recorded are : 19.25 by 

 14.75; 18.0 by 14.75; 18.5 by 15.0; 18.5 by 14.0 millimeters 



Young. — The incubation period is reported by Verne Dockham as 

 14 days and by L. H. Walkinshaw as 14 to 15 days. My extreme dates 

 for young on the nest are June 9 (1944) and July 17 (1930) , but most 

 dates of hatching come between June 11 and June 20. Hatching or- 

 dinarily occurs in the early part of the day. The female carries away 

 the eggshells. During the first day or two, the female may stay on the 

 nest much of the time and give to the young the food that the male 

 brings ; later both parents feed the young directly. Frequently a male 

 is observed that makes more trips to the nest than the female does. 

 When disturbed at a nest with young, both parents give quite elabor- 

 ate "injury feigning" displays. The young normally remain in the 

 nest 12 to 13 days. Only one brood is raised, but a second nest is 

 built if the eggs or small young in a first nest are destroyed. 



Plumages. — The natal down is "hair brown." The juvenal plumage 

 was described by N. A. Wood (1904) as follows : 



Above dark slate color, lighter on the head, each feather tipped with light 

 sepia brown; those of the mantle broadly edged with whitish spots; those of 

 the back, with buffy white ; wings and tail dark, slightly edged with light 

 brown ; * * * lesser and middle coverts * * * like the back ; * * * 

 greater coverts broadly edged with buffy brown, making distinct bars ; lores, 

 sepia brown ; sides of head otherwise similar in color to the upper parts, but 

 rather paler, fading gradually into pale buffy brown on the chin and throat, this 



