Northern Parula, Worm-eating Warbler and other unusual migrants at Aquiares

Aquiares is hitting the birding headlines at home in Costa Rica with a stunning combination of unexpected migrant warbler sightings, all of them at or near the laguna. Here we take a look at just 4 of them, in order of their supposed scarcity, while also remembering that the Yellow-breasted Chat is now no longer considered, by some authorities at least, to be a warbler.

Northern Parula (Setophaga americana): Parula norteña; Paruline à collier; Meisenwaldsänger

Worm-eating Warbler (Helmitheros vermivorum): Reinita gusanera; Paruline vermivore; Haldenwaldsänger

Yellow-breasted Chat (Icteria virens): Reinita grande; Ictérie polyglotte; Gelbbrust-Waldsänger

Ovenbird (Seiurus aurocapilla); Reinita hornera; Paruline couronnée; Pieperwaldsänger

As the time of writing, the Northern Parula is still to be found at the same location at Aquiares. While common in the United States this pretty little migrant warbler is decidedly uncommon Costa Rica and has been recorded in the Turrialba area on only a handful of occasions. Our resident Tropical Parula (Parula pitiayumi) is fairly common on the Caribbean side of the country and a pair is currently nesting in my garden. It can be easily distinguished from its northern cousin because it has just one wing bar, though often not easy to see, and a dark eye with no eye ring.

A rare Northern Parula at Aquiares; photo by John Beer
John’s first view of the Northern Parula at Aquiares with wing-bars clearly in view; photo by John Beer

Surprise warbler number 2, at the very same location, was another northern migrant, a Worm-eating Warbler. In the Turrialba area there have been only four reports so far this year, and guide Steven Aguilar was present for three of them! The bird’s name is a bit of a misnomer since vermivorum rarely, if ever, eats earthworms. The species chows down mostly on caterpillars and forages close to the ground, which is where, in North America, it also nests.

Worm-eating Warbler at Aquiares; photo by John Beer

The Worm-eating Warbler is a species that I have seen only once before, when banding at CATIE. It caused quite a sensation on that day too. Briefly held prisoner, however, it was considerably easier to photograph than Steven and John’s bird!

This Worm-eating Warbler caused quite a stir at the CATIE banding table where Alejandra displayed it to visitors.

The close-up shot below of the same individual shows that the Worm-eating Warbler lacks the dark ear-patch of the somewhat similar Costa Rican Warbler (Basileuterus melanotis):

Presumably all worms and such had already been digested! Photo by Paul Pickering

The third unexpected sighting at Aquiares this week was of a Yellow-breasted Chat, a species rated as very uncommon in Costa Rica. Identification was well verified and I believe the bird is likely to stay in the area, but in the meantime here’s a clear image of another chat that showed up, also in Aquiares, in mid-March 2018. One suspects that it might even be the same individual!

The so-called Reinita Grande (‘big warbler’): Yellow-breasted Chat, at Aquiares in 2018; photo by Larry Waddell

It is also perhaps notable that I documented on this blog my own first experience with a Yellow-breasted Chat in October 2014. This bird arrived in my garden in San Antonio that month but was never photographed. It stayed faithful to the underbrush, mostly near the back door, until April 2015!!

The fourth warbler of considerable note, the Ovenbird, is actually a rather common migrant in Costa Rica in most years. Only very recently, however, have reports from the Turrialba area begun to exceed very low numbers. Much of the credit for this goes, I believe, to the remarkable and fairly recent increase in the number of qualified home-grown Costa Rican observers. The first two images below show the latest sighting of this ground-loving species in Aquiares. First impression is often of a small thrush, but the final image – from the United States – shows more clearly the key field marks that will definitively identify this warbler.

Ovenbird at Aquiares; photo by John Beer
Ovenbird, profile view; by John Beer
Ovenbird in Florida showing striped crown and breast; photo by Karel Straatman

The information above by no means exhausts local reports of unusual, even rare, migrant warblers – Cape May, Yellow-throated, MacGillivray’s and Cerulean come immediately to mind. The Cape May Warbler (Setophaga tigrina), in particular, is now being reported annually from Turrialba and from the Province of Cartago in general. This was formerly considered a very rare species in Costa Rica, and thus a final image taken earlier this month, also at the Aquiares laguna, is entirely appropriate:

Immature Cape May Warbler at Aquiares; photo by John Beer

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