Shedding light on an odd bird - the Pale Rock Sparrow in Lebanon

International bird of mystery

Pale Rock Sparrow

Some birds are spectacular but the Pale Rock Sparrow Carpospiza brachydactyla certainly isn't. In fact, the definitive work on the birds of Europe and the Near East calls this bird, found only locally in the hills and mountains of the Middle East, "a bird of remarkable anonymity." Yet for all its dullness - it looks like a female House Sparrow - the Pale Rock Sparrow is an intriguing bird of considerable interest to biologists, and work by A Rocha ornithologists in Lebanon is helping to determine how it lives and how it can best be conserved.

Perhaps because it is so drab and so restricted in its occurrence, there have been few studies on the Pale Rock Sparrow and much about it remains mysterious. For a start, no one is even certain that it is a sparrow. Originally considered to be a true rock sparrow, it was long assigned to the genus Petronia. However, more recent work has shown that it is not very sparrow-like and there are suspicions that it may even be a finch or bunting. So until its true biological affinities are resolved, the Pale Rock Sparrow resides in a genus of its own, Carpospiza. Perhaps more important is the fact that its breeding behaviour is poorly known which makes conservation difficult. Given that there are concerns about the long-term future of this species, finding out what makes a good Pale Rock Sparrow nesting area is a matter of some urgency.

The research...

Slopes of Jebel Barouk where the Pale Rock Sparrow breeds

The Jebel Barouk ridge of the Lebanon Mountains which overlooks the Aammiq Wetland - the focus of much of A Rocha Lebanon's work - holds one of the westernmost breeding populations of the Pale Rock Sparrow. Given that so little of the ecology of these birds was understood, Chris Knight and Colin Beale carried out a detailed study in 2001 to try to establish what these birds looked for in choosing breeding sites.

It was known that the population (only discovered in 1999) bred in two zones, one below the woodland on the mountainside and another on the mountain tops. A strip of land about nine kilometres long in both zones was studied throughout the breeding season. Sparrow numbers and habitat measurements were recorded at forty sites across the study area. At each location, some fourteen aspects of the habitat were measured; these included such things as altitude, vegetation type, distance from human habitation, proportion of pebbles, gradient of slope, etc. In addition, the food (mostly insects) eaten by the birds was sampled throughout the breeding season.

...and the results

The survey showed that, across the study area, there were roughly two hundred pairs of Pale Rock Sparrows present in the zone near the valley floor and three hundred around the mountain tops. This is a sizeable population and gives these slopes a high conservation value for this species. The studies showed that the highest densities of breeding birds occurred in those areas with a steep slope, many small pebbles and few trees. A further result of the study was the demonstration that the breeding time was linked to a rise in beetle and grasshopper numbers and to the temperature reaching a daily average of over 18ºC.

This study has a number of implications for conservation:

The biggest threat to the Pale Rock Sparrow in this area is the loss of habitat as the villages and fields expand up the lower slopes of Jebel Barouk. The mountaintop sites are less threatened.
Any reduction in goat grazing in the lower zone might have serious long-term detrimental effects if, as a result, tree cover increased.
Anything that reduces beetle or grasshopper populations will be likely to damage the breeding success of this species.
Because some important aspects of the breeding habitat of the Pale Rock Sparrow, such as the steepness of slope and an abundance of pebbles, cannot be either controlled or constructed, conservation measures need to be directed towards the most appropriate areas.

For the long term, this work has provided some baseline data against which future populations of Pale Rock Sparrow can be compared. Should any management related habitat changes occur, it will be valuable to repeat this study to see if there have been population changes.

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This work was carried out by Chris Knight of the University of Oxford and Colin Beale of A Rocha. The help of the London University Convocation Trust and the Ornithological Society of the Middle East Conservation Research Fund is acknowledged. For further information contact christopher.knight@plants.ox.ac.uk or lebanon@arocha.org.