Frogmouths are a group of nocturnal birds related to nightjars. They are found throughout the tropics and subtropics of Asia, Australia, and Africa. Frogmouths are named for their large, wide flattened bills which resembles a frog’s mouth. There are 12 recognized species of frogmouths.
Some of the largest frogmouth species include the tawny frogmouth, Papuan frogmouth, and marbled frogmouth. In this article, we will explore the sizes of these large frogmouth species and discuss how big they can get. Understanding the sizes of birds can give insights into their ecology and evolution.
Tawny Frogmouth
The tawny frogmouth (Podargus strigoides) is one of the most common and widespread frogmouth species. It is found throughout much of Australia and Tasmania.
Tawny frogmouths are large, bulky birds with cryptic plumage. Their body feathers are tawny brown, finely patterned with black, white, and buff. This provides excellent camouflage during the day when they roost motionless in trees, disguising themselves as broken tree branches.
Length
The total length of tawny frogmouths ranges from 34-58 cm (13.4–22.8 in). Males average around 40 cm (15.7 in) while females average slighter larger around 44 cm (17.3 in).
The relatively large size makes them Australia’s biggest frogmouth species. For comparison, common nightjars in the region only reach 24–28 cm (9.4–11.0 in).
Wingspan
Tawny frogmouths have broad wings to support their large body size. Their wingspans ranges from 85–95 cm (33.5–37.4 in).
Again, females tend to be larger with average wingspans around 90 cm (35.4 in) compared to 86 cm (33.9 in) in males.
Weight
Weights range from around 250–750 g (8.8–26.5 oz), with males averaging lower around 250-500 g (8.8-17.6 oz) and females averaging higher 300-700 g (10.6-24.7 oz).
Key Facts
- Length: 34-58 cm (13.4–22.8 in)
- Wingspan: 85–95 cm (33.5–37.4 in)
- Weight: 250–750 g (8.8–26.5 oz)
- Females larger than males
So in summary, tawny frogmouths are stocky birds reaching lengths of over 50 cm, wingspans approaching 1 meter, and weights of up to 750 grams. The cryptic plumage and motionless roosting habits betray their true large sizes.
Papuan Frogmouth
The Papuan frogmouth (Podargus papuensis) is endemic to New Guinea. It inhabites rainforests across much of the island.
The Papuan frogmouth is the second largest frogmouth species after the tawny. It has silvery-gray plumage boldly patterned with black, white, and rufous markings. The vertical barring helps camouflage them against tree bark.
Length
Total lengths range from 40-50 cm (15.7-19.7 in). On average, males measure around 43 cm (16.9 in) and females 48 cm (18.9 in).
Wingspan
Wingspans range from 80-100 cm (31.5-39.4 in). Females tend to have longer wingspans nearing 100 cm (39.4 in).
Weight
Average weight is around 390 g (13.8 oz), but can reach up to 700 g (24.7 oz). As with other measurements, female Papuan frogmouths weigh more than males.
Key Facts
- Length: 40-50 cm (15.7-19.7 in)
- Wingspan: 80-100 cm (31.5-39.4 in)
- Weight: 390 g (13.8 oz) average, up to 700 g (24.7 oz)
- Females larger than males
The Papuan frogmouth is only slightly smaller than the tawny frogmouth. Its size is an adaptation to prey on large insects, small mammals, and even birds within the dense New Guinea rainforest habitat.
Marbled Frogmouth
The marbled frogmouth (Podargus ocellatus) is found in Australia, New Guinea, and nearby islands. True to its name, it has intricate marbled patterns in brown, black, white, and rufous.
It is a moderately sized frogmouth, though still reaching substantial proportions.
Length
Total length is 33-46 cm (13-18.1 in). Males average around 37 cm (14.6 in) and females 40 cm (15.7 in).
Wingspan
Wingspans range from 75-90 cm (29.5-35.4 in). Females tend to have wider wingspans than males.
Weight
Average weight is around 250-350 g (8.8-12.3 oz). Females at the upper end nearing 350 g and males at the lower end around 250 g.
Key Facts
- Length: 33-46 cm (13-18.1 in)
- Wingspan: 75-90 cm (29.5-35.4 in)
- Weight: 250-350 g (8.8-12.3 oz)
- Females larger than males
So while not as large as tawny or Papuan frogmouths, the marbled still reaches considerable sizes with its heavyset body, wide wingspan, and substantial weight.
Frogmouth Size Comparisons
To summarize the sizes of these large frogmouth species:
Species | Length (cm) | Wingspan (cm) | Weight (g) |
---|---|---|---|
Tawny Frogmouth | 34-58 | 85-95 | 250-750 |
Papuan Frogmouth | 40-50 | 80-100 | 390 average, up to 700 |
Marbled Frogmouth | 33-46 | 75-90 | 250-350 |
Key takeaways:
- The tawny frogmouth is the largest species, followed by the Papuan frogmouth
- Tawny frogmouths reach up to 58 cm long with 95 cm wingspans and 750 g weights
- Female frogmouths of all species average larger in size than males
- Even mid-sized frogmouths like the marbled have wingspans over 75 cm
Why Are Frogmouths So Large?
Frogmouths are among the largest nightjars. Their substantial sizes likely evolve for several key reasons:
Forest Habitats
Most frogmouth species live in tropical forests, including rainforests. Having a large body size allows them to capture wider prey variety, including small mammals and birds which are abundant in forests. Their broad wings help them navigate dense vegetation.
Sit-and-Wait Hunting
Frogmouths use a sit-and-wait ambush style hunting rather than chasing prey on the wing. Being larger provides stability when lunging at prey from a perch. Their wide gape allows them to swallow larger prey whole.
Camouflage
Their size lets them mimic broken tree branches when roosting. The marbled frogmouth’s wings can fully enclose its body while roosting. A smaller bird would be less convincing as camouflage.
Intimidating Rivals
Large sizes may also help frogmouths scare away potential rivals or predators in competition for nest sites and food resources.
Carrying Eggs
Females likely grow larger than males to accommodate having large broods of eggs. The tawny frogmouth lays up to 4 eggs over 60 mm long.
So in summary, frogmouths benefit from substantial sizes to hunt varied prey, utilize sit-and-wait techniques, camouflage themselves, compete for resources, and carry eggs. Their large but cryptic nature makes them a unique group among birds.
Conclusion
Frogmouths are characterized by their large, broad bills and sizeable bodies. The tawny, Papuan, and marbled frogmouths are among the larger species, with lengths up to 58 cm, wingspans to 100 cm, and weights approaching 750 g. Their considerable bulk likely evolves to take advantage of forest habitats, employ sit-and-wait hunting, camouflage themselves, compete with rivals, and carry large broods. Females tend to be bigger than males, possibly to accommodate egg-carrying. The next time you spot a frogmouth roosting cryptically on a branch, take a closer look at its true sizable proportions hidden beneath the camouflage plumage.