Immature: Resembles adult, but head, neck, scapulars, and secondaries edged with rufous; feathers of chin and throat edged with whitish. Younger birds may have less rufous on head but feathers of body more rufous with creamy edges.
Measurements.—Measurements are listed in [table 38].
Table 38. Measurements of Rhipidura rufifrons in Micronesia
Table 38. Measurements of Rhipidura rufifrons in Micronesia
| Subspecies | Number and sex | Wing | Tail | Exposed culmen | Tarsus |
| R. r. uraniae | 11 males | 66 | 78 | 13.6 | 16.6 |
| (64-69) | (75-82) | (13.1-14.5) | (15.6-17.2) | ||
6 females | 65 | 76 | 12.3 | 16.8 | |
| (61-68) | (73-81) | (11.6-12.5) | (16.1-17.6) | ||
| R. r. saipanensis | 7 males | 68 | 81 | 13.3 | 17.3 |
| (68-69) | (80-83) | (13.0-13.5) | (16.2-18.4) | ||
6 females | 64 | 76 | 12.7 | 17.9 | |
| (62-66) | (72-81) | (12.4-13.4) | (17.2-18.1) | ||
| R. r. mariae | 2 males | 65, 67 | 82, 82 | 12.1, 12.4 | 17.1, 17.2 |
| R. r. kubaryi | 14 males | 77 | 88 | 14.4 | 20.0 |
| (75-79) | (82-95) | (13.6-15.0) | (19.0-21.0) | ||
10 females | 72 | 87 | 14.5 | 20.0 | |
| (69-75) | (83-90) | (14.0-15.0) | (20.0-20.5) |
Weights.—The NAMRU2 party recorded the weights of nine males as 9.0-10.0 (9.0); of three females as 7.2-9.6 (8.8) grams.
Specimens examined.—Total number, 41 (19 males, 14 females, 8 unsexed), as follows: Mariana Islands, USNM—Guam, 17 (May 29, 30, June 6, 14, 18, July 12, 20); AMNH—Guam, 24 (Jan., Feb., March, Aug., Sept., Dec.).
Nesting.—Hartert (1898:54) recorded nests taken at Guam in February and March.
Molt.—On the basis of specimens examined, it is apparent that molt begins in August or September and continues through the months of the fall.