Hume’s Owl

Hewn out of pink sandstone, the ancient city of Petra, Jordan, overwhelms the ears as well as the eyes. At times it resembles an inverted tower of Babel, with all the world’s languages thronging its gorges and gouged out temples. Souvenir sellers and ‘air conditioned camel’ touts outshout the crowd, while Pallid Swifts Apus pallidus scream in and out of cliffs. Birders visit Petra mainly for Sinai Rosefinch Carpodacus synoicus, a regional endemic. Roy Slaterus and I spent hours recording their songs in any quiet eddies we could find on the fringes of the crowd. Then we had a long rest in the Royal Tombs, reawakening just as a full moon was rising. As hoped, the tourists had gone. A wistful melody from a distant flute underscored the silence, but for two hours Petra’s other speciality eluded us.

Just as we decided to give up, I noticed a dent in the outline of the moon. We slipped passed one Bedouin souvenir-seller who was asleep on his stall. Outside the Treasury, another was drinking tea by his tent. When we pointed to the growing lunar eclipse, he gasped, clearly even more surprised than we. A mile long cleft called the Siq is the usual entrance and exit to Petra. It is so narrow and deep that the diminishing moonlight illuminated only a narrow strip of cliff near upper rim. We walked quickly, hoping to exit in time to see the eclipse reaching totality. When we were almost there, a minor miracle took place. A distant Hume’s Owl Strix butleri started to hoot. Reaching the entrance, we climbed up a hillside where we could listen over the plateau. The owl was not so far away. CD4-39 is my first Hume’s Owl hooting under a blood red, fully eclipsed moon.

When Alan Octavian Hume described ‘Asio’ butleri in 1878, he created a mystery that has deepened with the passing of time. The eponymous Butler was a British Army Officer who had sent Hume the specimen, having received it from one Mr Nash. Hume believed Nash to be living in Ormara, a port on the Mekran coast in current day Pakistan. And here is the mystery: in the 136 years since its discovery there has not been another whiff of Hume’s Owl anywhere north of the Gulf of Oman, in Iran, Pakistan or anywhere else. [edit– but see Omani Owl footnote].

My second encounter with Hume’s Owl took place in southern Oman, six years after Petra. By this time owls had top priority, so René and I earmarked four nights for the nocturnal specialities of the region. Mike Watson, a tour-guiding friend, gave us a tip for Hume’s. In the afternoon of 15 April 2010, we made our way to the fantastically beautiful wadi complex behind the village of Mughsayl, which lies on the shores of the Indian Ocean. After driving several kilometres inland we continued on foot, wary of unexploded land-mines rumoured to be left over from the Dhofar Rebellion. It was only after this conflict ended in 1976 that Hume’s was discovered in the area, the furthest east that it has been proven to occur. As we worked our way around some huge boulders that had fallen to the wadi floor, we met a large herd of camels. The thunderous echo of their groans reassured me. They probably made the same journey every day, so I relaxed about the mines. 

Later in the evening two male Hume’s Owls exchanged compound hoots from different directions. One was close enough for a good recording (CD4-40) but after a short period of activity, all became quiet. René and I waited a couple more hours in vain. I decided to stay up as long as necessary but with nothing more concrete to focus on, René said good night and set off for the car. 

During the rest of the night I heard no more owls. At some point I lay down on a sandy spot and slept, oblivious to the scorpions I would find there on a later visit. At dawn I wandered back to the car, sweating profusely in the humid conditions. When I met René he had a smug grin. After leaving me he had taken a wrong turn, and so had his belly. Attending the call of nature first, he then decided to find a spot to rest and work out where he was in the morning. At this point a family of Hume’s Owls, dad, mum and the kids, started calling from a nearby cliff. René’s misfortune had led to the discovery of an active nest. The next night I recorded the family from dusk to dawn. 

I have a confession to make. I rarely use playback, but when I returned to the spot with Killian in February 2014 I did use it. After hearing nothing for nearly an hour after dusk, I simply wanted to know whether the old nest was occupied. On hearing the recording, made at exactly that spot four years earlier, the female replied immediately. She was almost certainly incubating, and hardly left the nest during two subsequent nights. Later when I heard her mate, I thought he sounded like the same male as before, based on his compound hooting. 

Next morning I tried again, this time with Killian and his camera ready beside me. The male responded by hooting until well after dawn from an alcove behind an acacia some 50 m away from the nest: his roost as it turned out. Many passerines mobbed him. I recorded CD4-41 just when the first White-spectacled Bulbul Pycnonotus xanthopygos dared to go in close. In later recordings the owl was almost drowned out by his detractors.

The commonest call of female Hume’s Owls during the breeding season is their soliciting call, a rising, whistled queee. On our 2010 visit I heard it for long periods during the night, much more than the male’s hooting. In 2014 it was the only sound I heard from the female at all (CD4-42). She used it almost every time the male was close to the nest. 

On two occasions I also heard the male using the soliciting call in exchanges with the female (eg, CD4-43). In both cases I now believe that he was the lower-pitched caller (contra Robb et al 2013). Female soliciting calls vary in pitch and timbre, but tend to be highest when the male is nearby and the female wants to be fed. Sometimes they become harsher, and occasionally they may be inflected downwards instead of the usual upwards.

Some Hume’s have much higher-pitched compound hoots than others, up to 1 kHz or higher, but the male from René’s nest was among the lowest. I am confident he was a male because in both 2010 and 2014 he hooted frequently and was highly mobile, whereas the female stayed at the nest and rarely gave anything other than soliciting calls. Although she never obliged me by proving it, I believe that high-pitched compound hooting belongs to females.

On 26 February 2014, I recorded another pair with a second set of equipment at a different spot some 600 metres from René’s nest. One of them gave low-pitched compound hooting while the other gave soliciting calls. In July 2013, at exactly the same spot, Arnoud had recorded two Hume’s Owls hooting, high and low-pitched. The higher-pitched one reached around 990 Hz and I conclude that it was the female (CD4-44).

In one dawn recording from 2010, when recording near René’s nest, I picked up two Hume’s Owls hooting several hundred metres away that I now believe were females (CD4-45). One of them is possibly the same as in CD4-44. The other, further to the right and more distant, deviates slightly from the usual rhythm. 

Pulsed hooting of Hume’s Owl consists of short series of pulses that usually rise in pitch and intensity. I used to think that they used pulsed hooting rarely and only for brief moments (Robb et al 2013), but in 2014 I learned otherwise. Remember the time I used a little playback? In the immediate aftermath only the female replied, but the male must have heard it too. About half an hour later I heard a sudden commotion at the border with his neighbour’s territory. Two males engaged in a confrontation that lasted nearly 19 minutes. 

If we listen carefully to CD4-46, both males are using a mixture of compound hooting and pulsed hooting but in different proportions. The slightly higher-pitched male from René’s nest gives far more pulsed hoots than his lower-pitched neighbour. My interpretation is that he was probably fired up by my use of playback half an hour earlier. When he caught up with his neighbour, he delivered a fierce and totally undeserved rebuke.

In 2010, I had recorded pulsed hooting only three times, always during brief encounters between male and female (CD4-47, CD4-48 & CD4-49). In all three, pulsed hooting followed a compound hoot, whereas in the male-male confrontation I just described the pulsed hooting consistently came first. 

One of the commonest calls at René’s nest in April 2010 was a series of very quiet, repeated and highly variable hoots delivered in a slow, faltering rhythm. Often, the notes became tremulous and broke up into a chittering sound. The sequence sometimes ended with a compound hoot. Usually it was the male making this sound (CD4-50), and on more than one occasion a nestling begged intensely at the same time. I interpret the sound as a feeding call. The female allowed the male to go straight to the nest with food, so perhaps male Hume’s feed their young directly. The female used this call less often, and only when the male was not around. Her version was markedly higher-pitched than his (CD4-51).

We could not see the young from René’s nest, but there were certainly two of them and they were probably at least two weeks old. I’m sure they felt quite safe up on their cliff. I only heard what I could easily recognise as a guarding call or ‘alarm call’ on two occasions. In CD4-52, the caller was probably the female. A few minutes later a possible Gordon’s Wildcat Felis lybica gordoni meowed once near the microphones at the base of the cliff. In CD4-53, the caller is certainly the female (the male was some distance away), and her first guarding call comes after I make a loud movement. Towards the end René moves too, and this elicits more calling. 

Immediately prior to this, both nestlings had been begging loudly (CD4-54). They had probably not been fed since the morning. The guarding calls silenced them for a moment, but soon one started calling again. Several times during the night, I recorded feeding sequences. In CD4-55, you can hear the female’s wingbeats as she brings prey at the start. The begging calls speed up and there are a couple of chitter calls, probably from one of the young. 

Although there is some variation in the timing of breeding (Jennings 2010), most juveniles are probably independent by August. Autumn calling has been reported in September (O’Reilly 2000, Mikkola 1983) and October (Megalli et al 2011), but tour guides consider Hume’s Owl notoriously difficult to hear outside the breeding season. James Smith (in litt) has heard some quiet gruff barking in November in the Dead Sea region of Israel. Perhaps this is the short, throaty cough sometimes heard between compound hoots by Leshem (1981), although he reported it from January to April. The only call I know that might fit this description was a deep tuc-tuc, given just once by the male when leaving René’s nest (CD4-56). 

The vocal repertoire of Hume’s Owl still leaves plenty for adventurous birders to investigate. I wonder if they are really so quiet in autumn for example, and I’m curious to know what calls they use most during that season. Perhaps we should listen for them in August on hot nights when 

juveniles must be dispersing but very few people have ever listened. It would be odd if Hume’s had no ‘distance call’ like Tawny Owl S aluco, which uses this call most often in autumn. 

It may seem strange to us now, but only a couple of decades ago Hume’s Owl was one of the least known birds of the Palearctic. When Arnoud first saw one in Israel in March 1977, field guides illustrated it with dark eyes (eg, Heinzel et al 1972). The map in Hüe & Etchécopar’s monograph on birds of the Middle East (1970) showed Hume’s only in Israel, Jordan and, mysteriously, southern Iran. The authors apparently did not know about specimens from central Saudi Arabia (Meinertzhagen 1930) and Sinai (Le Roi 1923). Discoveries of Hume’s on the east coast of Egypt (Baha el Din & Baha el Din 2001), in Oman, southern Saudi Arabia and Yemen were all published later.

Our knowledge of Hume’s Owl is gradually improving, but even in the 21st century, there is a great deal to learn. A major monograph on owls (König et al 2008) mapped Hume’s in northern Oman and the United Arab Emirates, for which there was no evidence at all. In March 2013, I did stumble across a Strix owl in northern Oman, however, and it opened up a whole new chapter in our knowledge of this genus.

>>> Omani Owl Strix butleri >>>