Horned Lark Has the Most Recognized Subspecies of Any Bird

Ledger + unique-singleton finding. The ledger is the full table of IOC v15.1 bird species ranked by subspecies count, plus aggregate statistics: 11,250 total species, 19,774 subspecies, 2,724 species (24.2 %) with at least one subspecies, 17 species with ≥20 subspecies, 4 species with ≥30, and exactly 1 species with ≥40 subspecies. The thesis is that the Horned Lark (Eremophila alpestris) uniquely holds the record for most recognised subspecies in the IOC v15.1 catalog, with 42 subspecies — 8 more than the tied runners-up (Eurasian Jay Garrulus glandarius and Mangrove Warbler Setophaga petechia, both at 34), a 23.5 % margin. Horned Lark is the ONLY bird species on Earth with more than 40 recognised subspecies, and the 30+ subspecies club has exactly four members (Horned Lark, Eurasian Jay, Mangrove Warbler, Common Pheasant). Extreme subspecific variation is not concentrated in one taxonomic family — the top five species by subspecies count span five different families (Alaudidae, Corvidae, Parulidae, Phasianidae, Passerellidae), so the tendency toward subspeciation emerges independently across the bird phylogeny. The Horned Lark's extreme variation reflects its Holarctic distribution across arid grasslands, where geographic isolation and local adaptation have produced morphologically distinguishable populations from North America through Eurasia to North Africa. Pinning the exact '42' count to a specific IOC release gives ornithologists and biogeographers a snapshot-pinned reference for an often-quoted but rarely-exact record.

Biologists divide bird species up into subspecies when populations in different parts of the world look reliably different from each other but aren't different enough to call separate species. Most of the roughly 11,000 bird species in the world have no subspecies at all — the population is uniform. Some have a few. The world's leading bird taxonomy authority, the International Ornithologists' Union, keeps a master list that tracks exactly which species have how many subspecies. I downloaded the current version (v15.1, released 2025) and asked: which species has the most? The answer is the Horned Lark, a small brown songbird found across grasslands in Europe, Asia, North Africa, and North America. It has 42 recognised subspecies. That's 8 more than the next closest species (Eurasian Jay and Mangrove Warbler both at 34). In fact, the Horned Lark is the ONLY bird species on Earth with more than 40 recognised subspecies. Only four bird species have more than 30, and only 17 have more than 20. The reason the Horned Lark is so varied is that it lives across an enormous range of climates and continents — from high Arctic tundra to hot deserts — and populations in each local habitat have diverged over thousands of years to look slightly different. If you know where to look, you can tell an Alaskan Horned Lark from a Moroccan one from a Colombian one just by plumage color. No other bird has diversified quite this much at the subspecies level. None of this is secret — bird taxonomists talk about Horned Lark as the 'champion of subspecies' — but putting the exact number on a specific IOC release, and noting that it's the only bird over 40, is a clean fact card.

42 Eremophila alpestris (Horned Lark) · 34 Garrulus glandarius (Eurasian Jay) · 34 Setophaga petechia (Mangrove Warbler) · 30 Phasianus colchicus (Common Pheasant) · 28 Zonotrichia capensis (Rufous-collared Sparrow) · 26 Chlorospingus flavopectus (Common Chlorospingus) · 24 Melospiza melodia (Song Sparrow) · 23 Lagopus muta (Rock Ptarmigan) · 23 Xiphocolaptes promeropirhynchus (Strong-billed Woodcreeper) · 22 Cyclarhis gujanensis (Rufous-browed Peppershrike)

11,250 species · 19,774 subspecies · 2,724 species with ≥1 subspecies · 17 with ≥20 · 4 with ≥30 · 1 with ≥40 (Horned Lark)

Horned Lark (Eremophila alpestris), 42 subspecies — 8 ahead of the 34-tied runners-up; the only bird in the world above 40 subspecies