
Nombre en español: Reinita de Antifaz
Nombre en inglés: Common Yellowthroat
Nombre científico: Geothlypis trichas
Familia: Parulidae
Categorías: Errática / Migratoria / Boreal
La mascarita común (Geothlypis trichas) también conocido como mascarita norteña; antifacito norteño, caretica, chipe de cara negra, cigüita enmascarada, cuelliamarillo común, enmascarado norteño, reinita de antifaz, reinita gorgigualda, reinita pica tierra es un ave de la familia de los parúlidos. Se reproducen de manera masiva en América del Norte con un área de distribución desde del sur de Canadá al centro de México.

La reinita de antifaz se encuentra asociada a cuerpos de agua y en su temporada de reproducción las hembras parecen favorecer a los machos con máscaras grandes. Su nombre Geotlypis deriva del griego geo = tierra y thlupis = ave pequeña. Trichas deriva del griego thrix = pelo.
Tamaño y Forma
Mide 11.5cm de largo y pesa 9.5g. El macho adulto es oliva parduzco por encima, color que torna verde oliva en la rabadilla y la cola. Exhibe una máscara negra que cubre la frente y los lados de la cabeza, y un borde blanco grisáceo por detrás. La garganta, el pecho y las cobertoras infracaudales son de color amarillo brillante y los flancos son café anteado brillante. La hembra no presenta máscara y es principalmente oliva en la cabeza. Sus parte inferiores son blanquesinas fuertemente teñidas de café y su garganta amarillo pálido.
Especies Similares
Puede confundirse con la Reinita Carinegra y la Reinita enmascarada, pero es más pequeño que otros Geothlypis y estas especies son enteramente amarillas por debajo y los machos no tiene borde gris pálido o blanco encima de la máscara negra.
Diferencias Regionales
Se reconocen 14 subespecies pero al parecer a Colombia sólo llega G. t. trichas.

Distribución
Las subespecies norteñas son migratorias que pasan al invierno en el sur de su área de reproducción, América central y las Antillas del Mar Caribe. Las cigüitas enmascaradas meridionales son residentes y en Europa son divagantes muy raras.
La Reinita de Antifaz se encuentra en la Costa Pacífica, la Sierra Nevada de Santa Marta y la Guajira. Anida en Norteamérica desde el sur de Canadá hasta México. Pasa la temporada invernal en el sur de Estados Unidos, Indias Occidentales, Panamá, Colombia y Venezuela.
Hábitat
Habitan en humedales con densa vegetación baja, y también se le puede encontrar en otras áreas con matorral denso. Por el contrario estos pájaros son menos comunes en lugares secos.Hembra.
Descripción
Las careticas tienen dorsos color café, gargantas amarillas, y vientre blanco. Los adultos machos tienen máscaras negras enmarcadas por una banda color plomo, solo en la parte de arriba. La hembras tienen un aspecto similar pero sin la máscara negra.
Las especies de éste pájaro del sudoeste de su rango tienen los colores amarillo más fuerte.
Subespecies
Hay 14 subespecies de esta ave, y sus diferencias son sobre todo en la apariencia y características de la cara del macho así como en el brillo de su pecho amarillo. Las subespecies del sudoeste de su área de distribución tienen los colores amarillo más fuerte.
Comportamiento
Las hembras parecen preferir machos con máscaras más grandes. Las mascaritas comunes forman nidos en áreas bajas de la vegetación, ponen entre 3 y 5 huevos en un nido con forma de vaso. Ambos padres alimentan a sus crías.

Las reinitas gargantiamarillas se alimentan de insectos quienes son atrapados entre los arbustos bajos y a veces en aire libre. Su canto es fuerte y alto.
Estado de conservación
Hay 32.000.000 en el mundo y son considerada una especie de preocupación menor. Sin embargo algunas subespecies están amenazadas y sus números están disminuyendo. Como la mascarita común de humedales salados de California.
Common yellowthroat
The common yellowthroat (Geothlypis trichas) is a New World warbler. It is an abundant breeder in North America, ranging from southern Canada to central Mexico. The genus name Geothlypis is from Ancient Greek geo, «ground», and thlupis, an unidentified small bird; thlypis is often used in the scientific names of New World warblers. The specific trichas is also from Greek; trikhas is a kind of thrush, the word being derived from trikhos, «hair».
Description
Common yellowthroats are small songbirds that have olive backs, wings and tails, yellow throats and chests, and white bellies. Adult males have black face masks which stretch from the sides of the neck across the eyes and forehead, which are bordered above with white or gray. Females are similar in appearance, but have paler underparts and lack the black mask. Immature birds are similar in appearance to the adult female. First-year males have a faint black mask which darkens completely by spring.

There are 13 races of this bird. These races differ mainly in the males’ facial patterns and the brightness of the yellow underparts. The southwestern forms of this bird are the brightest and the yellowest below.
Measurements:
- Length: 4.3-5.1 in (11-13 cm)
- Weight: 0.3-0.3 oz (9-10 g)
- Wingspan: 5.9-7.5 in (15-19 cm)
Habits
The breeding habitats of these birds are marshes and other wet areas with dense low vegetation, and may also be found in other areas with dense shrub. However, these birds are less common in dry areas. Females appear to prefer males with larger masks. Common yellowthroats nest in low areas of the vegetation, laying 3–5 eggs in a cup-shaped nest. Both parents feed the young.
Northern races are nocturnal migrants, wintering in the southern parts of the breeding range, Central America and the West Indies. Southern forms are largely resident. This species is a very rare vagrant to western Europe.
These birds feed on insects, which are usually captured in dense vegetation, but sometimes caught in midair.
The common yellowthroat’s song is a loud twichety twichety twichety twich. Its call is a soft jip.Singing male yellowthroat
Population
Despite a decline in numbers in some areas, which is due to loss of favoured habitat, this species is still very common.
Migration
Routes of migration vary based on the season and location of common yellowthroats. During fall migration, from August to October, common yellowthroats in Canada, Western, Eastern, and Central U.S., and regions outside of the United States all have unique migration routes. When migrating in the fall months, all adults and immature individuals tend to arrive at their migration destinations around the same time. Migration differences in timing and routes are also seen during the spring months from early February to late May in these same groups across the United States, Canada, and other areas. However, males generally arrive at their destination site before the females during the spring migration months. During both fall and spring migration, many birds take time to rest during a stopover period. Some individuals stay at their stopover destinations for several weeks or months while others spend only a few days resting before they continue on in their migration patterns to their final destination.
One place of study on common yellowthroat migration that is unique and worth noting is Appledore Island, Maine. Common yellowthroats here typically migrate to this island during the spring months displaying distinct patterns of movement and stopover ecology. Analysis of the common yellowthroat spring migration from April to June was observed by researchers from the Department of Biology at Canisius College in Buffalo, New York, to determine patterns of migration and time spent resting on the island before continuing on their journey. Birds returning for more than the second time arrive earlier than birds migrating to the island for their first time. Every year, males tend to arrive on the island an average of five days earlier than females weighing more than the females upon arrival. One possible explanation for the early arrival of males to this island is the ability of males to set up territories before the females arrive. This could give them better access to resources and a higher likelihood of finding a female. However, both sexes spend about a week on the island before leaving.
Migration of common yellowthroats in Florida has also been extensively studied. In Florida, the common yellowthroat can be found more often in the southern peninsular region rather than the northern panhandle region closer to the mainland of the United States. Peak migration times of the birds in this region are during the last week of September through the second week of October. Not as much is known about spring migration in Florida, but the patterns appear similar to that of the autumn migration.
Future studies are needed to understand specific migration patterns of common yellowthroats in other parts of the United States.

Fuentes: Wikipedia/eBird/xeno-canto/WikiAves