North America’s familiar Common Yellowthroat turns out to have thirteen cousin species, all members of the genus Geothlypis and all characterized by a yellow throat and black mask, although the size of each varies considerably across the fourteen species. Southern Yellowthroat is the newest member of the genus, split from Gray-crowned Yellowthroat just two years ago. It’s also one of the warbler species most recently photographed by WC.

This species is a little less closely associated with marshy areas than its Common Yellowthroat cousin, adapted to a variety of habitats. It ranges across southern Brazil, Uruguay, Paraguay and northern Argentina. It’s not well studied, but its adaptation to human-disturbed habitats make it fairly commonly glimpsed.

“Glimpsed” because this is a famously skulky species, foraging in dense tangles of brush and understory. It’s a bit maddening to try to photograph; WC took dozens of photos of the bird partially obstructed by sticks and vegetation and only two marginally acceptable shots out of about fifty. If the two birds WC saw are representative, this is an extremely active bird, outdoing its warbler cousins.

Like other warblers, this is primarily an insectivore, gleaning and hawking insects. It has one specialty: it’s attracted to termite colonies where the birds forage on the wing at swarms of termite alates.

The nest is built low to the ground, well-concealed, in a variety of habitats. On limited evidence, the female builds the nest. There are 2 – 4 eggs, incubated solely by the female for about 14 days. The nestlings are fed for about 10 – 11 days before fledging. It’s unclear whether the male participates in feeding the nestlings. There’s no published information on fledgling or post-fledging behavior.

There’s almost no information on survivorship and there are no studies yielding population estimates. Like a lot of South American bird species, the Southern Yellowthroat is largely unstudied.

The IUCN – the International Union for Conservation of Nature and Natural Resources – is the resource WC uses to report a species’ status. The 2021 split of Masked Yellowthroat establishing Southern Yellowthroat as a separate species is too recent for IUCN to have updated its database. The Masked Yellowthroat was last assessed in 2016, and based on its wide range, adaptation to human disturbance and range of habitats, it was identified as a species of Least Concern. Notably, there’s no quantified data – zilch – on populations. More evidence, if you needed it, on how little we know about the planet we are buddy destroying.

For more bird photographs, please visit WC’s bird photo site, Frozen Feather Images.