The Same Heron, Two Continents Apart

Back in December 2023, I wrote about my first Striated Heron, spotted while we walked through Ibirapuera Park in São Paulo. On weekends, the park’s 390 acres (158 hectares) fill with thousands of people, so I was surprised to find a heron wading calmly through it all. The featured image here is that São Paulo bird.

Fast forward to June 2026. On our latest trip to Brazil, we visited several UNESCO World Heritage Sites in Minas Gerais — the colonial cities of Ouro Preto, Mariana, São João del Rei, and Tiradentes, and the Igreja de São Francisco de Assis in Pampulha, on the edge of Belo Horizonte. It was outside that church, along Pampulha Lake, that a second Striated Heron caught my eye, tucked into the grass and doing what these herons do best: waiting.

Seeing the two birds side by side in my catalog got me thinking about one I know far better from home in Texas: the Green Heron. The resemblance is striking, and it is no coincidence.

One Species, Then Three

Put a Striated Heron (Butorides striata) and a Green Heron (Butorides virescens) next to each other, and the family resemblance is obvious: same compact build, same dagger bill, same habit of freezing into a crouch before uncoiling to strike. For much of the twentieth century, in fact, ornithologists treated them as one bird — together with the Galápagos’ Lava Heron, they were lumped into a single wide-ranging species called the Green-backed Heron.

The split came late in that century, once researchers weighed plumage, calls, and genetics. Three species were pulled apart: the Green Heron of North and Central America and the Caribbean; the pantropical Striated Heron (Butorides striata); and the Lava Heron (Butorides sundevalli), endemic to the Galápagos. Genetic work shows the Green and Lava Herons are closest kin, with the Striated branching off just before — one ancestral heron whose populations drifted apart once oceans and geography kept them from mixing.

That, in short, is how the two became separate: not through any dramatic event, but through geography. Cut off from each other, the North American and tropical populations evolved different plumage — the Green Heron a warm chestnut neck, the Striated a cooler gray — plus different voices and genes. Biologists call it allopatric speciation: new species arising from populations kept apart.

The story has a footnote, though. Where the two ranges meet, in central Panama and the southern Caribbean, they still interbreed, producing a zone of hybrids with intermediate neck colors. Yet even there each tends to pair with its own kind — a sign they are still drifting apart rather than merging. Speciation, it turns out, is less a clean break than a slow separation.

Where in the World

What makes the Striated Heron remarkable is its reach. While the Green Heron is essentially an Americas bird, the Striated is pantropical — found from eastern Panama to northern Argentina, across sub-Saharan Africa and Madagascar, through southern Asia, and out to Australia, in roughly thirty subspecies. So the next time a small, hunched heron holds still at the edge of a Brazilian lake, remember: its relatives circle much of the tropical world, and its family tree was redrawn only a generation ago.

That is the story behind the shots. If you liked this post, you may also be interested in others featuring Belo Horizonte, Bird of the Week, Brazil, Ibirapuera, Minas Gerais, São Paulo, Striated Heron, and Wildlife. Until the next time, keep clicking and capturing the beauty your eyes find.

Posted for I.J. Khanewala’s Birds of the Week Invitation CLXXVII.

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Sources:

• Cornell Lab of Ornithology, Birds of the World — Striated Heron (Butorides striata), Systematics — https://birdsoftheworld.org/bow/species/strher2/cur/systematics
• Cornell Lab of Ornithology, Birds of the World — Green Heron (Butorides virescens) — https://birdsoftheworld.org/bow/species/grnher/cur/introduction
• Wikipedia — Butorides — https://en.wikipedia.org/wiki/Butorides
• Wikipedia — Striated heron — https://en.wikipedia.org/wiki/Striated_heron
• Wikipedia — Green heron — https://en.wikipedia.org/wiki/Green_heron
• HeronConservation (IUCN SSC Heron Specialist Group) — Striated Heron — https://heronconservation.org/herons-of-the-world/list-of-herons/striated-heron/
• Zwiers et al. — Variation and hybridization in Green Heron and Striated Heron in central Panama, with comments on species limits — https://www.researchgate.net/publication/259868747