Black-thighed Falconets, Part ll - nestlings

 Approximately 4 weeks of incubation, I had my first sighting of a skink prey taken into the nest, which was uncommon as before, big prey was usually shared on the perch outside, which suggested that chick/s had been hatched; on this day there were also five deliveries of dragonflies, moths and butterflies into the nest within one hour. 

Showing continued alertness and awareness before delivering food to the nest.

Trying to bite off the skink head before taking it into the nest.

Feeding still comprised mainly moths, butterflies and dragonflies caught within the 50m radius of the nest, either while the bird was on perch taking a breather or flew out directly from nest for the prey.

However in the first week there was no regularity or frequency in feeding.  Sometimes there was no feeding for two whole hours except for a couple of moths and dragonflies; sometimes it was for almost three hours.

(On hindsight this was probably because the chicks were hatched at different times so at this stage there was probably only one chick in the nest.)

A small Atlas moth prey would be cleaned up before taking into the nest.

Sometimes the catch would be handed over to the other if both were outside together to take into the nest, mainly from the male to the female.

Big preys such as lizards, young birds or chicks tended to be delivered early in the morning, midday or late afternoon or evening.

It did not take much imagination to identify what these preys were.

Lizards, skinks and birds were increasingly caught for food.  However, sometimes it was difficult to identify the bird preys as these would be de-feathered and torn loosely somewhere before arriving for delivery to the chicks. Moths, butterflies, dragonflies caught within the 50m radius of the nest were delivered immediately into the nest. 

Discards such as tiny bones, wings and other unidentified parts were frequently seen ejected from or carried off the nest.

When a big prey like this Flying Lizard was delivered it was common for the pair to come together first, perhaps to look out for any snatcher?  The female was seen to enter the nest to await the male to deliver the prey who only entered more than 5 minutes later perhaps so as not to reveal the nest location to the many birds in the vicinity.

After about 20 minutes, the lizard that was - skeleton now, was taken out by the female to be eaten on a distant branch.

Nothing went to waste with this parent.

Just as well as the parents had to feed themselves too and they were seen to do so with small catches like moths while resting outside the nest.

A butterfly offering from the male.

A piece of leftover bird prey taken out to be finished off nearby.

Some discards were simply Discards.

Finally a waste sac sighted.

Two days later thick nestling poops that attracted flies suggested that the chicks were now strong enough to discharge out of the nest albeit weakly.

From the second week onwards vertebrate preys featured regularly as their catch - sometimes within half an hour each one brought back usually a bird or lizard prey each.  

An early morning delivery.

Further tearing loose the prey before delivering into the nest.

Whilst at it, this parent decided to have some for himself.

Meanwhile the pair still showed heightened alertness and sensitivity being watched or thought that they were being watched and would delay carrying food into the nest.  If it happened to carry out remains of a prey it would fly off to a distant perch but not to its regular perch to eat.

When the coast was clear ....

Also, the pair had to continue to fend off inquisitive visitors.

The pair seen to be able to leave nest unguarded now for brief period of 5 to 10 minutes, as they flew off to preen or bathe together. 

Approximately more than two weeks later three chicks were seen who could be approximately 11-15 days old.

Could there be another one or two more as it's not uncommon for the Black-thighed Falconets to have a brood size of 2-5?

Two chicks were seen to be able to discharge out of the nest.

The female parent was still removing a fecal sac (that was subsequently eaten by her) even as the other chicks were already able to squirt out of the nest. 

The fecal sac

Some observations and deductions:

1. As it was difficult to know precisely when chicks were hatched in a cavity nest, signs like increased feeding, change in preys in terms of dietary changes, and parents' behaviour had to be used to suggest chick presence eg. during incubation, when a bird prey was caught the parents would consume this on an open perch; however when chicks were hatched it was observed that bird preys were taken into the nest after being torn loosely although still in one piece.  However lizards, skinks, bats and even a rat were taken in whole.

The female came across as the more aggressive one bringing back bigger preys.  Yet she was the one who spent more time in the nest with the chicks.

Smaller preys were carried directly into the nest and bigger ones sometimes handed to the female by the male if he was the one who caught the preys.

2. If there was a big prey caught in the morning, there was less feeding for the next few hours which accounted for the irregularity in the number of feedings; more small preys were fed when the pair failed to make a big catch.

[AI overview:

Hatchlings: chicks are altricial — blind and helpless at hatching, requiring intensive parental care.

Feeding: both parents provision chicks. The male typically supplies most prey brought to the nest, delivering prey items to the female at the cavity entrance or directly into the nest during her absences. Prey items are small birds, large insects, and sometimes small vertebrates; parents tear prey into suitable pieces for chicks.

Rate of provisioning: feeding visits are frequent, increasing as chicks grow. Parents may cache small items near the nest entrance briefly to speed deliveries.

Brood size management: with larger clutches, competition among chicks can be intense; mortality of weaker chicks is recorded in raptors generally and occasional brood reduction has been noted in falconets.]

3. The parents had to continue to be on guard as intruders especially Common Flamebacks kept returning to check out the nest.  Perhaps it's breeding time for these woodpeckers who were also searching for a location or perhaps, this nest was used before by the woodpeckers.

[AI overview:

Territoriality: breeding pairs defend the immediate nesting territory vigorously against conspecifics and other small raptors. Aerial chases and calling are used to repel intruders.

Nest defense: parents will harass approaching predators and mob small intruders; larger predators (snakes, large arboreal mammals, bigger raptors) can still take eggs or nestlings.]

4. The parents continued to be highly alert to their surrounding when delivering food into the nest.  They either delayed their delivery or one would call out to the other to exit for the prey to be taken in.

Black-thighed Falconets, Part l - incubation

 The hostile encounter between a Black-thighed Falconet (Microhierax fringillarius) and a Spectacled Spiderhunter (https://rimbakiara.blogspot.com/2026/03/falconet-vs-spiderhunter.html) which ended in the Falconet flying into the taman and not off and away as he would typically had probably foretold that he had set up a presence in the taman.

For the next couple of weeks I did not notice any unusual activity or increased presence of a pair of Falconets which unfortunately meant that I did not monitor their movements.

And then one morning I saw a female Falconet feasting on a bat joined later by the male who came with a butterfly.

Perhaps even the Spotted Dove knew then of the potential threat this pair of Falconets would pose if the pair decided to nest in the taman as it tried to intimidate off the lone Falconet, to no avail.

And then it happened as I tracked the male as it flew down, and into a hole in a branch!

A surveillance was initiated.

The soon-to-be parent

During the period from mid March onwards, ie after the pair was observed to enter and exit the cavity nest albeit not regularly, I was still uncertain whether the pair had started incubation.  This was because they were constantly indulging in courtship behaviours like allopreening, courtship feeding, and even copulation.

An insect prey was offered by the male to the female who in turn offered it back to the male, and then watched him enjoy it.  Was this courtship?

It's playtime as the couple indulged in a bath together in the hollow of a tree on a hot day.

The male remained behind for some 'me' time.

During this period the pair also engaged in copulation.

Allopreening happened frequently.  This kind of preening which typically takes place on the head or neck is one of the most adorable characteristics of the black-thighed falconets.

Anytime, anywhere.

Preening was most required too following long periods cooped inside the nest to fluff off parasites and mites acquired in the cavity nest.

And then it's the female's turn to show some affection for its mate, and self-rejuvenation.

 

Signs of incubation were deduced in late March when the pair took turns to be inside the nest but it was the female who tended to stay longer inside the nest compared to the male who normally remained inside for less time before he emerged to fly off and not to return until a couple of hours later.  

When he returned with a catch he would give an alert cry and would either fly straight into the nest with the prey or the female would emerge to take the prey from him.

The nest was not left alone; there's always one on the watch outside when none was inside the nest.

Preening came naturally whenever the pair got together.

However the female or male left alone inside the nest could be seen to fly out regularly too to take a breather.

The female exiting to stretch and preen by herself.

Preys were normally delivered whole directly into the nest and whoever did so would exit almost immediately. 

The male delivering food to the female.

It was mainly a drop-and-go delivery, this time of a dragonfly.

Making another rather clumsy entrance with a dragonfly catch.

Sometimes the male would call out to the female to exit the nest to receive his prey offer.

It was not uncommon for the male to consume a prey himself while outside the nest.

The male constantly displayed impatience as it emerged from the nest to look out for the female, also frequently leaving the nest when she could not be seen in the vicinity.  However he would remain in the immediate vicinity.

Fluffing and stretching after emerging from the nest.

Food for the pair were primarily small preys such as moths, butterflies, beetles and dragonflies.  Occasionally there were dead birds eaten on the perch outside the nest.

A carpenter bee prey in the early morning.

Most times it's not easy to identify the prey when what's left was just a piece of feather when the falconet was spotted or what was being brought was a plucked bird.

At other time it was evident what was devoured earlier.

Sometimes it felt like a prey was simply too pretty to be caught!!

When a catch was not completely eaten by one in the nest, it was taken out to be finished off by the other.

Unfortunately this beetle was dropped as it had been observed too before of other half-eaten preys in similar circumstances, due to clumsiness!?

At this stage, squirrels and birds like woodpeckers, mynas, magpie robins were seen regularly to attempt to check out the hole nest, going near or even managing to almost peer into the hole whilst one bird was inside the nest.

A Common Flameback was braver when it came to checking out the nest.

And a week later this one was at it again.

And then after almost 4 weeks' incubation I was able to made a reasonable conclusion that chicks had been hatched.

Some general observations and deductions:

1. It is uncommon for a pair of Black-thighed Falconets to nest in such a low and open or exposed branch that hang over a rather busy walkway in an urban park; the nest is less than 15ft high.  This cavity nest was probably used by woodpeckers or barbets before as this park regularly plays host to these nesting species.  

In addition, this pair could be deduced as first time parents as they had nested independently away from other falconets, perhaps due to their ignorance of typical black-thighed falconets' communal nesting and subsequent communal chick-feeding.

The cavity nest was probably chosen because of the eye-level and open perch available directly across the nest.  The falconets could fly straight into the nest from any of the perches across the nest or even from one particular distant open perch.

(Interestingly, approximately a month after the falconets made the hole their nest, a pair of Banded Woodpeckers came to excavate and occupy a cavity nest just about 6ft above the falconets' nest on the very same branch!)

[AI overview:

Habitat: forest edges, secondary growth, plantations, wooded river valleys and clearings ....  They favour open or semi-open woodland with perches for hunting.

Nest sites: they do not build exposed stick nests.  Instead they nest in cavities - natural tree holes, old woodpecker/barbet cavities - hollow bamboo internodes, and occasionally fissures or crevices in dead trees.  In some areas they've been reported using holes in earthen banks or abandoned termite nests, though tree cavities are most typical.

Site choice factors: entrance size, depth and dryness of cavity, concealment from predators, proximity to good hunting perches and abundant prey (small birds, large insects.

Nest: falconets do not construct an elaborate nest lining.  They may remove loose debris and occasionally line the cavity with few feathers or plant fibres, but often leave the cavity largely bare.  There is little to no nest-building visible compared with passerines.]

2. The pair of falconets took about 3-4 weeks to incubate.  They displayed typical courtship behaviours like courtship feeding, allopreening, playful pursuits around the nest area before and during incubation, vibrant and rapid high-pitched exchanges when coming together in or outside the nest, and copulation.

It was the female that spent most of the time in the nest whilst the male would deliver food to her or call her out to offer her the catch.  The male spent less time in the nest and sometimes disappeared for a few hours before returning to perch opposite the nest.

[AI overview: 

Displays: courtship includes short aerial chases and fast direct flights between perches; conspicuous calling (high thin whistles) during flights; mutual chasing may include rapid direction changes and swoops.

Courtship feeding: males commonly present prey to females at perches and at the nest entrance (food transfer).  This food-offering functions both to strengthen the pair bond and to provision the female during incubation.  Mutual preening and and close perching are reported around nest sites.

Allopreening: Allopreening refers to a social grooming behavior in birds where one individual uses its beak to clean, groom, and arrange the feathers of another bird. It most commonly takes place on the head and neck, areas that are difficult for the receiving bird to reach on its own.Beyond basic hygiene, allopreening serves vital social and biological functions within the avian world.

Strengthening Bonds: It is heavily practiced by mated pairs to build and maintain strong partnerships. It is also common among flock members to solidify group cohesion.

Parasite Control: It helps remove ticks, mites, and dead skin particles that can accumulate in hard-to-reach areas.

Relieving Tension: In larger flocks, this mutual grooming ritual can help defuse aggression and reduce conflict between birds.

Egg-laying and clutch size: reported clutches typically range from 2 to 5 eggs, most commonly 2-4.

Egg appearance: eggs are generally pale, often whitish or buff with fine speckling (description varies with source)

Incubation: incubation is primarily by the female, though the male returns frequently to feed her and may incubate briefly.  Reported incubation periods in Microhierax species are roughly in the order of 20-30+ days, exact figures for M. friggillarius may vary by site and are not universally consistent in literature.

Attendance: the female stays in the cavity for long stretches, leaving briefly to to be fed by the male or to hunt, especially early or late in the day.]

3. Both birds displayed continued intense alertness and aggressiveness at being watched, bobbing their heads and staring at the camera lens if aimed at them.  Once, the female left the nest to fly and flutter directly in front of my camera lens, an uncommon behaviour.

On another test occasion, I lingered outside the nest with the camera aimed at the hole entrance, the female flew out, swooped down brushing past my lower legs before she flew into the nest to exit immediately again, perched and 'eye-balled' me.

A final test occasion was planting myself right opposite of the nest entrance, aimed my camera at the entrance, and within seconds her head popped out, and she flew out right over my head that I had to duck!

On one occasion this heightened wariness was displayed too with other birds close-by when the female arrived with a dead chick.  She was plucking the feathers of a dead bird as if ready to take it into the nest.  However, with a Black-naped Oriole foraging close-by, and as if to not reveal the nest, she flew off to a distant perch and finished off the bird prey by herself!

She only returned an hour later to the nest with a beetle prey.

Another strategy was to delay entering the nest with preys whenever there were birds in the immediate vicinity of the nest.

And it’s the female that’s always the aggressive one.

Both male and female were always on the alert before entering or exiting the nest.

Male

Female

Even during copulation the male was aware of being watched!

During preening, watching from afar.

Exiting with a discard.

Whilst on perch.

At bath!

Aggression

Playtime