- Order: Passeriformes
- Family: Tyrannidae
- Polytypic 6 Subspecies
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).
The vocalizations of some populations of White-crested Elaenia are well-known, but apparently are not well known for some other subspecies, such as the intra-tropical migrant subspecies modesta.
The dawn song of the southern subspecies chilensis is a short, slightly raspy two- or three-note phrase, e.g., these examples from Chuquisaca, Bolivia (at the northern limit of the distribution of chilensis), and from Jujuy, Argentina. The call of chilensis, at least on the breeding grounds, is 'feeeo' or 'feeo-feeo' (the Chilean name for White-crested Elaenia is 'fío-fío'); this call may be repeated incessantly for long periods.
The dawn song of griseogularis has been transcribed (Lane, in Schulenberg et al. 2007) as a series of deep, burry, falling-rising 'djeewee ' notes interspersed with occasional 'per'brr'djwee' notes. Daytime calls of griseigularis are raspier than the call of chilensis. The call of modesta is a pure, descending 'peeur' (Lane, in Schulenberg et al. 2007).
Detailed Description (appearance)
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)
Six subspecies currently are recognized, which fall into three groups (each of which may represent a separate species).
Resident Andean taxa:
1) Elaenia albiceps griseogularis Sclater 1858. Resident in the Andes from southwestern Colombia south to northwestern Peru. Similar to nominate albiceps, and not always distinguishable by plumage; averages paler in color on the upperparts, with less white in the crown, a shorter crest, and a less distinct eye ring.
2) Elaenia albiceps diversa Zimmer 1941. Resident in north central Peru. Similar to griseogularis, but the throat is whiter, the wing bars are less distinct, and there is more contrast between olive flanks and the white belly.
3) Elaenia albiceps urubambae Zimmer 1941. Residnet in southeastern Peru (Cuzco). Paler above than nominate, with less prominent eye ring or pale lores, the wing bars are duller, the belly may have a pale yellow wash, and bill is slightly heavier.
4) Elaenia albiceps albiceps (d'Orbigny and Lafresnaye 1837). Resident from southeastern Peru (Puno) to south central Bolivia (Cochabamba).
Austral migrant taxon:
5) Elaenia albiceps chilensis Hellmayr 1927. Breeds from southern Bolivia, northern Chile and northern Argentina south to southern Chile and Argentina; most populations are migratory. Darker olive above, with whiter and more contrasting eye ring and lores, a whiter coronal stripe, narrower and more sharply defined wing bars, and paler, whiter underparts. This subspecies also often has a longer primary extension than other subspecies, with the 10th (outermost) primary longer than the 5th.
Intratropical migrant taxon:
6) Elaenia albiceps modesta Tschudi 1844. Breeds in western Peru and northwestern Chile; migratory. This is the most divergent subspecies. Plumage duller overall with a greatly reduced facial pattern (little or no eye ring, and lores showing little or no contrast) and duller, less distinct wing bars. Also, pale edgings on the inner remiges extend all the way to the base of the feather; in other subspecies, these bases are dusky, contrasting with the pale edgings farther out the remiges.
White-crested Eleania often is believed to be closely related to Small-billed Elaenia (e.g, Hosner 2004). Small-billed Elaenia and the northernmost populations of albiceps chilensis locally hybridize in southern Bolivia, although hybridization has not been reported where their distributions overlap in northwestern Argentina (Traylor 1982). In contrast, a phylogenetic survey of Elaenia, using both mitochondrial and nuclear DNA sequence data, produced a very different pattern: White-crested Elaenia (based on samples from Peru and Argentina) is sister to nominate Sierran Elaenia (E. pallatangae), whereas Small-billed Elaenia is in a separate clade within the genus and is sister to Yellow-bellied Elaenia (E. flavogaster) (Rheindt et al. 2008).
A more detailed phylogenetic survey of Andean taxa of Elaenia, again using both mitochondrial and nuclear DNA sequence data, demonstrated that the White-crested Elaenia is polyphyletic (Rheindt et al. 2009). The southern austral migrant chilensis forms a clade that is separate from a clade made up of resident taxa (represented by albiceps and griseogularis). This survey unfortunately did not include any representatives of the distinctive taxon modesta, which has been considered a separate species by some authors (e.g. Zimmer 1941).
Hybridization has been suspected between albiceps griseogularis and nominate Sierran Elaenia (E. pallatangae) in southwestern Ecuador (Zimmer 1941), although this has not been confirmed through field studies. Rhenidt et al. (2009) reported evidence of genetic introgression between nominate Sierran Elaenia (E. pallatangae) and the chilensis subspecies of White-crested Elaenia.
Schulenberg, Thomas S.. 2009. White-crested Elaenia (Elaenia albiceps), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=30734