Notes and Observations

Siyoth Vol. 2 (1): 47 – 48

Some observations on the Brown Hawk Owl(Ninox scutulata hirsuta)
Amila Salgado,146A, Pahala Bomiriya, Kaduwela, Sri Lanka. Email: amila@birdwingnature.com
Introduction
The Brown Hawk Owl (Ninox scutulata) is widely distributed inwell-wooded areas of the Oriental region (Konig et al. 1998).
In Sri Lanka it is represented by the subspecies hirsuta, whichis also present in southwestern India (Rasmussen andAnderton, 2005). It is distributed from lowlands tomountainous zone in well-wooded areas in Sri Lanka (Legge1880). It is one of the few owls that can be seen in homegardens in Colombo.
A pair of Brown Hawk Owls are regularly heard andoccasionally sighted in and around my home garden inBomiriya, Kaduwela. The following observations are largely
based on my random personal observations carried out up toNovember, 2006.
Figure 1. Brown Hawk Owl (Ninox scutulata hirsuta) October,
2006, Bomiriya, Kaduwela,
Initial sighting
On 15 March 2006, I observed a Brown Hawk Owl flying from my home garden towards aneighbouring coconut grove around 6.15 p.m. It perched in a branch about 4 m from the ground in
one of the trees. It then made several sallies and caught and fed on, what appeared to be ‘coconut
beetles’ (Oryctes rhinoceros and Rhychophorus ferrugineus). Soon it was joined by another owl thatis probably its mate and they were seen perched close together.
Moments later, the bird, which was sighted first made a sallying flight and returned to the perch withan insect, which looked like a ‘coconut beetle’ and offered it to the newly arrived bird. I was curious
to find out whether this behaviour was part of ‘courtship feeding’. However, no mating took place
except for the fact that the donor maintained close proximity.
Day roost
As the bird was first sighted in my home garden, I was curious to find out its day roost. I therefore,
searched possible trees in my garden without any success. However, I was able to see them regularly
at dusk. Finally on 25 March 2006, I was able to discover the day roost by accident. It was in a dense
live fence consisting of coffee trees (Coffea arabica) in a corner my home garden. It was about 1 m
above the ground. This live fence was overrun by wines and the birds were seen roosting in an
umbrella-like cover inside them. My initial discovery flushed them out as I had unknowingly got too
close to them.
Unfortunately this live fence was reduced to a few trees by my neighbour and thereafter the bird wasseen in another coffee tree in my garden on the 28 Sep, 2006 perched 2 m above the ground just 5m away from its earlier roost. After a few days it had disappeared. Shortly afterwards, it was

Journal of the Field Ornithology Group of Sri Lanka

rediscovered in a Mango tree (Mangifera indica) about 5 m above the ground under a well hidden
shady spot. At the time of writing (November 2006) it could be seen singly or as a pair in this newday roost. As mentioned in the literature (Legge 1880, Konig et al. 1998) the Brown Hawk Owl willreadily fly out of the roost if it is disturbed so observers should be mindful of this fact whenapproaching day roosts.
Emergence from the day-roost & feeding.
As stated in the literature (Legge, 1880, Henry 1971, Konig et al. 1998), the Brown Hawk Owls
appear out of the roost at dusk when considerable amount of light is still available. According to myobservations, after leaving the roost they almost always perch about 1-4 m above the ground. Thenthey make low sallying flights to capture various flying insects about 1-6 m above the ground. They
capture them with their talons and return to a perch for feeding. When beetles are fed upon they canbe seen breaking and discarding certain parts of their body first before nibbling at it. I have also seen
them catching and feeding on moths. As mentioned in Konig et al. (1998), I have also found them to
be more active during cloudy weather. On heavy rainy days they abandon their regular roost to selecta more airy perch nearby about 4 m above the ground.
Threat from drongos
Their emergence out of the dayroost coincides with the last minutes of activity of several diurnal
birds most notably White-bellied Drongo, which usually can be seen hunting for insects until it is very
dark. One of the interesting things that I have experienced almost on a daily basis is the hearing ofseveral White-bellied Drongos uttering a characteristic alarm call at dusk, which continues intensely
on certain occasions.
After starting to observe the Brown Hawk Owls more closely, I found out that these alarm calls are
actually mobbing calls directed mainly towards the pair of Brown Hawk Owls as they emerge fromthe day roost coinciding with the last few minutes of activity of the White-bellied Drongos. Thedrongos numbering 4-6 could be often seen trying to ‘dive bomb’ the owls and chase them from thearea but eventually when the owls disappear from their sight the mobbing ceases.
Pellets
According to Legge (1880) they feed almost exclusively on beetles, moths and grasshoppers.
However, Konig et al (1998) reports that in addition to insects the diet of Brown Hawk Owls consistedof frogs, lizards, small birds, mice and occasionally insectivorous bats. I was able to collect several
pellets of the Brown Hawk Owls under their dayroost and after studying them I was able to find theremains of Beetles only, which confirms my visual observations. Therefore, it may be possible toattract Brown Hawk Owls to coconut grooves by planting low perching posts as a means of effective
biological control of these pests. This is provided that there are wooded habitats close by which could
function as suitable day roosts for the owls.
Sightings after dusk & calling
I noticed that after feeding actively closer to the ground at dusk, they seem to move away fromground level when dusk has given way to complete darkness of the night. During this time theirpresence could be detected by their calls heard from heights of 10-20 m above the ground.
Acknowledgements
I would like to thank Dr. Devaka Weerakoon for commenting on the manuscript. Special thanks to mymother Kanthi Salgado for her assistance with field observations.
References.

Journal of the Field Ornithology Group of Sri Lanka

Henry, G.M. (1998) A Guide to the birds of Ceylon. Kandy, Sri Lanka & New Delhi, India: Thirdedition. KVG de Silva and Sons and Oxford University Press.
Konig, C., Weick, F. and Becking., J (1999) Owls: A Guide to the Owls of the World. Mountsfield,Sussex, UK: Pica Press.
Legge, W.V (1983) A History of the Birds of Ceylon. Second edition. (4 vols.) Colombo: Tisara
Prakasakayo. First edition in 1880.
Rasmussen, P.C. and Anderton, J.C. (2005) Birds of South Asia. The Ripley Guide. Vols 1 and 2.
Smithsonian Institute and Lynx Edicions, Washington, D.C and Barlelona.
Salgado, A (2006) In: Ceylon Bird Club Notes. P 91-92

Journal of the Field Ornithology Group of Sri Lanka