The White-crested Elaenia easily is recognizable as an Elaenia by the combination of drab plumage (primarily dull green above, and whitish below); wings with conspicuous wing bars (pale tips to the greater and median wing coverts); slightly crested appearance, with a semiconcealed white center to the crown; and upright posture.
The White-crested Elaenia is a small- to medium-sized member of the Elaenia. It is smaller than Yellow-bellied (E. flavogaster), Large (E. spectabilis), Mottle-backed (E. gigas), and Highland (E. obscura) elaenias. Among the medium-sized elaenias, White-crested is very similar to Small-billed Elaenia (E. parvirostris); these two species have only limited overlap when breeding (although locally the two species hybridize), but can overlap during the nonbreeding seasons. White-crested Elaenia also is similar to Lesser Elaenia (E. chiriquensis) and to Sierran Elaenia (E. pallatangae), two species with which there is broad geographic overlap in the central Andes. See Similar Species for guidelines on distinguishing White-crested Elaenia from these species in the field.
The White-crested Elaenia can be very similar to several other small to medium-sized Elaenia; not all individuals can be distinguished in the field (or even in the hand). The most similar species are Small-billed Elaenia (Elaenia parvirostris), Lesser Elaenia (Elaenia chiriquensis), and Sierran Elaenia (Elaenia pallatangae).
White-crested Elaenia overlaps narrowly as a breeding bird with Small-billed Elaenia, in northwestern Argentina and in southern Bolivia. Hybridization between these two occurs in Bolivia, but is not reported from farther south in Argentina (Traylor 1982). White-crested and Small-billed elaenias also may overlap during non-breeding seasons. Small-billed Elaenia usually is paler and whiter on the underparts than other small Elaenia (including White-crested Elaenia), with greater contrast between the olive auriculars and the white throat. Most other small Elaenia, including White-crested, have grayer throats, but some individuals of the austral migrant subspecies chilensis can be white-throated as well. These individuals of chilensis usually still retain a slightly dingier, less “crisp,” demarcation between the throat and the auriculars. Small-billed Elaenia also often has a pale tips to the lesser wing coverts (forming a third wing bar, in addition to the wing bars on the median and greater wing coverts), which is lacking in other Elaenia; the crest often is relatively reduced in size; and Small-billed Elaenia has a more prominent eye ring.
The migratory chilensis subspecies of White-crested Elaenia has a long, more pointed wing tip. In chilensis the outermost primaries are 10th (outermost) primary usually is longer than the 5th primary (Zimmer 1941, Traylor 1982, McGehee and Eitniear 2006). This character can help to distinguish, at least in the hand, chilensis from Small-billed Elaenia and from other subspecies of White-crested Elaenia. White-crested Elaenias that breed in southern Bolivia, however, are similar to chilensis in plumage but usually do not have the elongated 10th primary (Traylor 1982). Even in southern Chile (Magallanes Province, Chile), up to 12% of the individuals sampled did not exhibit the typical chilensis wing formula (McGehee and Eitniear 2006); therefore it is not a surprise that in some specimens (Field Museum of Natural History) of non-breeding White-crested Elaenia from Peru that resemble chilensis in plumage the 10th primary is not appreciably longer than the 5th (T. Schulenberg, pers. obs.).
White-crested Elaenia also is very similar to Lesser Elaenia Elaenia chiriquensis. Typically the Lesser Elaenia is yellower below, especially on the belly; the center of the belly is relatively white in White-crested Elaenia. The wing bars of Lesser Elaenia also typically are washed with pale yellow; the wing bars of White-crested Elaenia are whiter.
The White-crested Elaenia usually can be distinguished easily from Sierran Elaenia Elaenia pallatangae by the white or light gray underparts, rather than the yellow underparts of Sierran. The nominate subspecies of Sierran is suspected of hybridizing with E. albiceps griseogularis in southwestern Ecuador (Zimmer 1941), although this situation has not been studied in detail.
The migratory modesta subspecies of White-crested Elaenia differs from all other subspecies of White-crested Eleania, as well as from the Small-billed, Lesser, and Sierran elaenias. The wingbars of modesta are less conspicuous, and the bases to the inner remiges are brown, not black.
The above summary of the identification of White-crested Elaenia draws on the discussions in standard field guides: Hilty and Brown (1986), Ridgely and Tudor (1994), Ridgely and Greenfield (2002), and Schulenberg et al. (2007).
A small to medium sized Elaenia with a white coronal stripe, a small bushy crest, and white or light gray underparts. No sexual dimorphism. The following description is based on nominate albiceps; see Geographic Variation for notes on other subspecies.
Adult: Sides of crown, auriculars, nape, back and rump dull olive or olive-gray. Coronal stripe, partially concealed, white or creamy white. Narrow whitish eye ring and lores. Wings dusky. Tips of median and greater coverts white or whitish, forming two wing bars. Tertials broadly edged whitish. Remiges narrowly edged whitish or yellowish; these edges extensive on the outer remiges, but the bases of the inner remiges are dusky. Tail dusky, rectrices narrowly edged with olive. Throat light gray or whitish gray; breast light gray or grayish-brown, often slightly darker than throat; bellywhitish.
Juvenile: Similar to adult, but the coronal stripe is reduced or absent, and the wing bars are less distinct and are yellower.
Iris dark brown. Maxilla black or dark gray; base of mandible pale (light brown, flesh or pinkish-flesh), often tipped dark. Tarsi and toes black or dark gray.
Length 13.5-15 cm
Mass 16.3 g, range 12.5-24.2 g (n = 55)