Here we are, in the Costa Rican highlands, and today the first Wilson’s Warbler (Cardellina pusilla) appeared in the garden, high in a rainbow eucalyptus. This is said to be the only migrant warbler to be found at the very;highest elevations in the country, and it is indeed much more common in the San Antonio area (1300 m) than down at Turrialba (700 m). Today’s bird is a very handsome male, all bright yellow with a neat black cap.
Identification problems arise only with females and immatures, which are easily confused with the corresponding Yellow Warbler (Setophaga petechia) females and immatures. However, the latter species often gives a much repeated chip call as it forages, and when it flies the yellow tail edgings are noticeable. The only other confusion might be with the juvenile female Hooded Warbler (Setophaga citrina), but that species is not at all common here, forages quite low down and the white in its tail feathers is quite striking.
Migration seems to have arrived rather earlier this year. Other migrants now here in San Antonio are the Barn Swallow and the Black-and-white Warbler, and each day brings fresh interest as I try to establish earliest first dates for the rest of the visitors from North America.