Photos of the Tawny Frogmouth (Podargus strigoides), with its huge yellow eyes, gaping mouth, “expressive face” (an impression given by the feathery “eyebrows”) and owl-like plumage, have captivated me since childhood. For years, I stalked Whip-poor-wills, Nighthawks and other of its relatives that dwelled in the USA. Actual contact with a Frogmouth was delayed, however, until I began working at the Bronx Zoo. But it was worth the wait, and I soon came to spend many days and nights cramming food into the capricious maws of hungry Frogmouth chicks…as much to my delight as theirs!
Although superficially resembling an owl in plumage, silent flight mode and nocturnal ways, the Tawny Frogmouth is classified in the order Caprimulgiformes. Numbered among this group’s 118 members is the cave-dwelling Oilbird, the only bird known to navigate via echo-location.
Tawny Frogmouths are placed in the family Podargidae, along with 14 relatives. Three Tawny Frogmouth subspecies – the largest being 3x the size of the smallest – have been described. Other species include the Papuan Frogmouth, of the Cape York Peninsula and New Guinea, and the Marbled Frogmouth, a rainforest dweller found in northern Queensland and New Guinea.
The 8 North American relations belong to the family Caprimulgidae (loosely translated as “goat-suckers”). I’ve observed 2 of these, the Whip-poor-will (Caprimulgus vociferous) and the Common Nighthawk (Chordeiles minor), in the heart of NYC. In fact, the swooping, erratic flight of Nighthawks, which resemble outsized bats, was a common sight over Bronx buildings in my youth. Flat rooftops serve Nighthawks as nest sites, but their numbers have declined in recent years. The Chuck-will’s-widow (Caprimulgus carolinensis), first recorded in New York in 1975, has been observed nesting on Staten and Long Island.
You’ll need to visit a zoo if you wish to see a Tawny Frogmouth in the USA, but wildlife rehabilitators in Australia are frequently called upon to care for displaced chicks and injured individuals.
During the day, Frogmouths perch on dead limbs, relying on their mottled plumage to provide camouflage. They often stretch upward, in imitation of a branch, as well. Frogmouths make great exhibit animals, content to perch in full view all day; however, they do become stressed if denied logs or stumps. I’ve kept several in exhibits lit by red bulbs, where they have proven to be surprisingly active.
Frogmouths under my care bred well but did not always raise their chicks successfully. Hand-rearing, however, was usually successful.
Frogmouth chicks have appetites that match their enormous mouths, and, even by baby bird standards, consume an amazing amount of food. Chopped mice are the standard zoo diet, but given that they are largely insectivorous, I experimented with other foods as well. Roaches, grasshoppers, moths, earthworms, insectivorous bird diet, beef heart and other such foods were eagerly consumed.
I do not have my old notes on hand, but recent studies have shown that hand-reared Frogmouth chicks often gain 8-9 grams per day, consistently, before fledging.
Most zoos provide only mice or chicks to their Tawny Frogmouths. I’ve cared for several that have bred and lived into their early teens on this diet, so it appears adequate. However, my Frogmouths showed a very strong response to large insects, especially roaches and grasshoppers. While it’s difficult to maintain birds of this size on invertebrates alone, occasional meals certainly add to their quality of life.
Although mainly ambush predators that pounce on prey from above, Frogmouths also hunt actively…at least when stimulated by novel foods. They have also been observed chasing moths around street lights.
Close Call with a Cassowary (for me and a frogmouth!)
Frogmouths remain largely immobile, but are very aware of their surroundings…a fact I learned the hard way. After working with one individual for some time, I came to expect him to remain perched on his favorite stump as I serviced his cage in one of the Bronx Zoo’s off-exhibit areas. He did…until he didn’t!
One day, he flew past me and out the door…taking off without a sound when I turned my back. Knowing that birds sense and follow air currents, I first ran to close the building’s unscreened kitchen window (a notably foolish feature in a bird building!). I returned to find that the wayward Frogmouth had flown into the pen occupied by Margie, a notoriously ill-tempered Cassowary (please see article below). The Frogmouth froze, head stretched up, in the species’ classic camouflage pose – perplexing Margie enough to make her pause. She circled, itching to kick the intruder into oblivion, but did not charge. I grabbed a “push board”, entered, and was able to catch the frightened Frogmouth before either of us could be attacked.
The Tawny Frogmouth is found across the length and breadth of Australia, and also occurs on Tasmania and several offshore islands.
Although most common in sparsely-wooded scrub and forest clearings, the Tawny Frogmouth also inhabits rainforest edges, overgrown farmland, gardens and city parks. It is absent from deserts and rainforest interiors.
Field studies have shown that beetles, moths, spiders, centipedes, snails and other invertebrates make up approximately 95% of the diet. Frogs, lizards and small mammals comprise the balance.
Most Frogmouths drink infrequently, if at all.
Reproduction occurs seasonally in most habitats, or in response to rains in arid regions. Most observers report that the male incubates the 2-3 eggs by day, with both parents entering the nest cavity at night. The eggs hatch in 27-31 days and the chicks, which are fed by both parents, fledge when they are approximately 1 month old.
Although most populations are stable, cats, foxes and cars pose increasing threats. Secondary pesticide poisoning is also a concern.
Tawny Frogmouths can tolerate quite high and low temperatures. In common with several related species, they can become torpid during cold nights – hibernating, in essence, for short periods.
Tawny Frogmouth image referenced from wikipedia and originally posted by Arpingstone
Tawny Frogmouth and chicks image referenced from wikipedia and originally posted by Skewmeister
Tawny Frogmouth Camouflage image referenced from wikipedia and originally posted by Apathetic Duck
Tawny Frogmouth and chicks image referenced from wikipedia and originally posted by Duncan McCaskill