Collared Falconet: Diminutive Predator of the Aerial World

I first saw the collared falconet (Microhierax caerulescens) in Buxa Tiger Reserve in 2001 while conducting a workshop on Important Bird Areas. After the usual indoor discussions and lectures, evenings and mornings were spent birdwatching since everyone gathered there was a keen birdwatcher. I vividly remember the “oohs” and “aahs” that travelled in the group when a pair of collared falconets was spotted, hunting butterflies in the canopies of sal trees. At that height, the falconets looked like large butterflies as they mimicked the fluttering pattern of their prey.

Falconets are small birds of prey distributed in Asia’s tropical and semi-tropical forests, from India eastward up to Indonesia. The black-thighed falconet (Microhierax fringillarius) is found in Myanmar, Thailand, Malaysia, Singapore, and Indonesia. One species, the white-fronted falconet (Microhierax latifrons), is endemic to Borneo. The collared and pied (Microhierax melanoleucos) falconets are found in India. The last of the five species of falconet is the Philippine falconet (Microhierax erythrogenys), endemic to the Philippines.

The collared falconet is found in India, Bangladesh, the lower parts of Bhutan, Myanmar, Thailand, Laos, Vietnam, and southern China. In India, the species is found throughout the lower Himalayan foothills from Garhwal eastwards to Assam, Arunachal Pradesh and other northeastern hill states, usually up to 900 m altitude. However, there are reports of some individuals at 2,000 m. I have seen this bird in Kaziranga, Manas, Nameri and Sonai Rupai wildlife sanctuaries. Corbett Tiger Reserve is a good area to see these birds, where my friend and BNHS colleague, Rishad Naoroji, worked on raptors in the 1980s and 1990s.

Just as small owls are called owlets (e.g. forest owlet, jungle owlet), small falcons are called falconets. The name falconet derives from the French word “fauconnet”, which means “little falcon”. Like their larger cousins, falconets are known for their agility and speed when they pursue small birds, butterflies, dragonflies, and other large insects.

Collared falconets are seen in small parties of 5-10 individuals, sometimes more, generally on the upper canopy of forests. In the evening, many individuals gather to roost communally, sometimes up to 20 individuals together. They are found in evergreen, deciduous, and moist-deciduous forests, generally flying high up in the canopy of tall trees. They prefer forest edges, where butterfly and dragonfly diversity is high (insects on which they prey). The birds also prefer forest edges because they can see the insects easily against the clear sky. Such visibility is difficult in dense forests, where insects can easily escape detection.

While foraging, they like to sit on a bare branch from where they make sallies to catch insects and return to the same perch. They are capable of hunting small birds, too, but mostly eat large aerial insects. If an opportunity arises, they may pluck a lizard or a cicada from a tree trunk. Like other falcons, the collared falconet has remarkable hunting skills, relying on speed and agility to capture prey mid-flight. Its hunting technique often involves perching in strategic locations, such as exposed branches or powerlines, from where it launches swift and precise attacks on unsuspecting prey, pursuing it for a considerable distance. In a study conducted by BNHS scientists at Buxa Tiger Reserve, out of 84 prey items, 61 per cent were butterflies, 2 per cent cicadas, 2 per cent lantern flies, 2 per cent birds (Nepal house-martins), and 1 per cent lizards. Almost 32 per cent of its prey could not be identified.

Usually inconspicuous, these birds are easily missed by casual birdwatchers. But in the breeding season, starting in spring, they become conspicuous as their courtship is noisy. Two falconets have been observed exchanging leaves; this could be a courtship ritual, as many birds give “gifts” to their mates. Gifts are generally a food morsel, but why does the falconet give a leaf? No one knows. Perhaps it is a hint to start nest building. Falconets are hole nesters, generally occupying old nests of woodpeckers or barbets. In a study in Thailand, the cooperative feeding of chicks has been observed. Here, two males and a female were seen assisting the parents in providing the chicks in a nest with food. We do not know if the nest helpers were the parents’ chicks from the previous year (i.e. siblings of the new chicks).

We do not know if the nest helpers were the previous year’s chicks of the pair. We also do not know whether cooperative breeding is common in collared falconets. Rishad Naoroji, an expert on raptors, studied the collared falconet in Corbett Tiger Reserve and found that three items delivered to a nest were all birds. Rishad writes in his paper published in the Journal of the Bombay Natural History Society, “The female mostly remained perched on a bare horizontal branch, while the male flew intermittent sorties of a short duration, returning frequently to perch excitedly alongside the female before flying off. On these sorties, the male would often pluck dried sal leaves with the feet in active flight and deposit them in their nest-hole. The larger leaves frequently got wedged at the nest-hole entrance and were dropped. Sometimes, he would perch alongside the female with the leaf (an offering?) before depositing it in the nest. After each sortie, when the male alighted alongside the female, the pair greeted each other with calls, the male additionally attracting the female’s attention by frequently spreading his wings. The pair would perch close, indulging in much bill-touching and cheek-preening initiated mainly by the male, occasionally by the female. Clumping and extended bouts of allopreening (grooming each other) appear to be common among the sociable Microhierax falconets.”

The collared falconet faces several challenges that threaten its long-term survival. Habitat loss due to deforestation and human encroachment pose significant threats to its populations, depriving it of essential nesting sites and prey resources. Pesticides have depleted its prey. As far as I know, it was not in trade in India. Rajat Bhargava, working on bird trade for the last 35 years, mentioned that he had seen a collared falconet only once in a bird market in India, in the Nakhas bird market in Lucknow in 1987. That bird was apparently brought from Nepal.

The collared falconet stands as a testament to the marvels of evolution and the intricate beauty of nature. This diminutive bird, adorned with striking plumage and endowed with remarkable prowess, captivates both ornithologists and casual observers alike. It is of “Least Concern” on the IUCN Red List, but these days, every species is of concern, particularly raptors, due to their position at the apex of the ecological pyramid. We need a comprehensive study to know its ecology, food availability, habitat requirements, nesting success, and status in India. Though widely distributed, it was nowhere common, or are we missing them in the foliage of tall trees?