Ceylon frogmouths in the Western Ghats

The frogmouths (Podargidae) are a group of nocturnal birds related to owlet-nightjars, swifts, and hummingbirds. Species in the group are distributed in the Indomalayan and Australasian realms.

Biology

They are named for their large flattened hooked bill and huge frog-like gape, which they use to capture insects. The three Podargus species are large frogmouths restricted to Australia and New Guinea, that have massive flat broad bills. They are known to take larger prey, such as small vertebrates (frogs, mice, etc.), which are sometimes beaten against a stone before swallowing. The ten Batrachostomus frogmouths are found in tropical Asia. They have smaller, more rounded bills and are predominantly insectivorous. Both Podargus and Batrachostomus have bristles around the base of the bill, and Batrachostomus has other, longer bristles which may exist to protect the eyes from insect prey. In April 2007, a new species of frogmouth was described from the Solomon Islands and placed in a newly established genus, Rigidipenna.

Their flight is weak. They rest horizontally on branches during the day, camouflaged by their cryptic plumage. Through convergent evolution as night hunters, they resemble owls, with large front-facing eyes.[citation needed]

Up to three white eggs are laid in the fork of a branch, and are incubated by the female at night and the male in the day.[citation needed]

Taxonomy

DNA-DNA hybridisation studies had suggested that the two frogmouth groups may not be as closely related as previously thought, and that the Asian species may be separable as a new family, the Batrachostomidae. Although frogmouths were formerly included in the order Caprimulgiformes, a 2019 study estimated the divergence between Podargus and Batrachostomus to between 30 and 50 mya and forming a clade well separated from the nightjars and being a sister group of the swifts, hummingbirds, and owlet-nightjars. The name Podargiformes proposed in 1918 by Gregory Mathews was reinstated for the clade.

Species

A pair of tawny frogmouths resting in a tree fork during the day
  • Genus Podargus

Tawny frogmouth, Podargus strigoides Marbled frogmouth, Podargus ocellatus Papuan frogmouth, Podargus papuensis

  • Genus Batrachostomus

Large frogmouth, Batrachostomus auritus Dulit frogmouth, Batrachostomus harterti Philippine frogmouth, Batrachostomus septimus Gould's frogmouth, Batrachostomus stellatus Sri Lanka frogmouth, Batrachostomus moniliger Hodgson's frogmouth, Batrachostomus hodgsoni Sumatran frogmouth, Batrachostomus poliolophus Javan frogmouth, Batrachostomus javensis Blyth's frogmouth, Batrachostomus affinis Sunda frogmouth, Batrachostomus cornutus Palawan frogmouth, Batrachostomus chaseni Bornean frogmouth, Batrachostomus mixtus

  • Genus Rigidipenna

Solomons frogmouth, Rigidipenna inexpectata

In culture

In a journal article published in April 2021, researchers Katja Thömmes and Gregor Hayn-Leichsenring from the Experimental Aesthetics group at the University Hospital Jena, Germany, found the frogmouth to be the most "instagrammable" type of bird. Using an algorithm to analyze the aesthetic appeal of more than 27,000 bird photographs on Instagram, they found that photos depicting frogmouths received the highest number of likes relative to the posts' exposure to users. The journal article was picked up by several news outlets, including The New York Times and The Guardian.

Summary of extant species

Common nameBinomial namePopulationStatusTrendNotesImage
Large frogmouthBatrachostomus auritusunknownVUAlthough population is unknown, species is listed as Vulnerable due to rapid deforestation across its known range.
Gould's frogmouthBatrachostomus stellatusunknownNT
Solomons frogmouthRigidipenna inexpectata1,500 - 7,000NTEstimate given is for population of mature individuals. Total population is estimated to be 2,500-9,999 individuals.
Sunda frogmouthBatrachostomus cornutusunknownLC
Dulit frogmouthBatrachostomus hartertiunknownLC
Hodgson's frogmouthBatrachostomus hodgsoniunknownLC
Javan frogmouth (Horsfield's frogmouth)Batrachostomus javensisunknownLCThe IOC splits two additional species, Blyth's frogmouth (B. affinis) and Palawan frogmouth (B. chaseni) from this species. IUCN/BirdLife International maintain all three species under B. javaensis.
Bornean frogmouthBatrachostomus mixtusunknownLC
Sri Lanka frogmouthBatrachostomus moniligerunknownLC
Sumatran frogmouthBatrachostomus poliolophus> 10,000LCPopulation value given is a very rough estimate, extrapolated from the large availability of suitable habitat on Sumatra.
Philippine frogmouthBatrachostomus septimusunknownLC
Marbled frogmouthPodargus ocellatusunknownLC
Papuan frogmouthPodargus papuensisunknownLC
Tawny frogmouthPodargus strigoidesunknownLC

External links

  • on the Internet Bird Collection