Buttonquails: The Unique Shorebirds of the Turnicidae Family
Buttonquails, also known as hemipodes, are a specialized group of small ground birds belonging to the family Turnicidae. While their appearance and name suggest a close link to true quails, they are actually members of the order Charadriiformes, making them more closely related to shorebirds than to the game birds of the order Galliformes.
These elusive birds are primarily found in the warm, tropical grasslands of Asia, Africa, Europe, Australia, and New Guinea. With 18 recognized species across two genera, buttonquails have evolved a lifestyle centered on running rather than flying, blending seamlessly into their terrestrial environments.
Key Facts
- Taxonomy: Despite their name, they are shorebirds (Charadriiformes), not true quails (Galliformes).
- Distribution: Found in tropical grasslands across Africa, Asia, Europe, Australia, and New Guinea.
- Social Structure: Most species exhibit sequential polyandry, where females mate with multiple males.
- Physical Traits: They lack a crop and a hind toe, distinguishing them from true quails.
- Parental Care: In the genus Turnix, the male is solely responsible for incubating eggs and raising chicks.
Taxonomy and Evolution
The classification of buttonquails has shifted significantly over time. The genus Turnix was first introduced by Pierre Bonnaterre in 1791, and the family Turnicidae was established by George Robert Gray in 1840. Historically, these birds were grouped with cranes (Gruiformes) or pheasants (Galliformes) due to their physical resemblance.
Modern scientific analysis, including DNA-DNA hybridization and sequence data, has corrected this placement. Buttonquails are now recognized as an ancient lineage within the shorebirds. This is supported by fossil evidence, such as the Turnipax from the Early Oligocene epoch.
Physical Characteristics
Buttonquails are small, terrestrial birds designed for life on the ground. They are divided into two genera: Ortyxelos and Turnix.
- Quail-plover (Ortyxelos): The smallest species, measuring 10 cm in length and weighing approximately 20 g.
- Turnix species: These range from 12 to 23 cm in length and weigh between 30 and 130 g.
A defining biological feature of the female buttonquail is a specialized vocal organ. This consists of an enlarged trachea and an inflatable bulb in the esophagus, which allows the female to produce a distinct booming call.
Breeding and Behavioral Patterns
One of the most striking aspects of buttonquail biology is their mating system. While the quail-plover is believed to be monogamous, species in the genus Turnix practice sequential polyandry—a system where one female mates with several males in succession.
The breeding process follows a specific cycle:
- Nest Building: Both sexes cooperate to build a scrape nest on the ground, typically near overhanging vegetation.
- Egg Laying: The female lays a clutch of 4 or 5 eggs.
- Incubation: After laying, the female leaves to find another mate, leaving the male to incubate the eggs.
- Hatching: Eggs hatch synchronously after 12 to 15 days.
- Development: The chicks are precocial (born in a relatively mature state) and are cared for by the male. They can fly by two weeks and are independent by four weeks.
Species Overview
| Genus | Notable Species | Distribution/Status |
|---|---|---|
| Ortyxelos | Quail-plover | Smallest species |
| Turnix | Common buttonquail | Includes extinct subspecies (Tawitawi) |
| Turnix | Black-breasted buttonquail | Tropical grasslands |
| Turnix | Painted buttonquail | Includes Abrolhos subspecies |
| Turnix | New Caledonian buttonquail | Possibly extinct (early 20th century) |
Frequently Asked Questions
Are buttonquails actually quails?
No. Despite their name and appearance, buttonquails are taxonomically unrelated to true quails (Galliformes). They are actually shorebirds belonging to the order Charadriiformes.
What is sequential polyandry in buttonquails?
Sequential polyandry is a mating system where a female mates with one male, lays eggs for him to incubate, and then leaves to mate with a different male, repeating the process.
How do buttonquails differ physically from true quails?
Buttonquails differ from true quails in two primary anatomical ways: they lack a crop (a muscular pouch near the throat) and they lack a hind toe.
Which sex is more colorful in buttonquails?
Unusually for most bird species, the female buttonquail is the more richly colored of the two sexes.
How long does it take for buttonquail chicks to become independent?
Buttonquail chicks are typically able to fly at two weeks of age and become fully independent by four weeks.