Habitat selection by Northern Bald Ibis on their Syrian breeding grounds

Bald ibis foraging amongst cereal crop, Morocco — Image: Chris Gomersall

Project objectives
Work planned or underway
Results
Species affected (not UK birds)
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There are only a handful of northern bald ibises left breeding in Syria. They differ from the main population in Morocco because they migrate to the Arabian peninsular and Ethiopia for the winter. They occupy an area of desert-like steppe in south central Syria but only make use of very specific sites to feed in from year to year when so much suitable-looking habitat appears to be available to them. We investigated whether these patches have special characteristics that cause them to be favoured by the birds.

Project objectives

The objective was to understand why the preferred foraging sites were so important. If we found that these patches had rare characteristics of importance to the birds it would confirm that it is a high priority that these particular sites are protected from any development or degradation.

Work planned or underway

Project has now been completed.

Results

Fieldwork was conducted between April and July 2008 with staff from the Syrian Ministry of Agriculture and Agrarian Reform and the assistance of the BirdLife Middle East office. The main focus was on the food supply in these patches so we compared the available prey items in areas used by the birds with areas that seem to be avoided. We used pitfall traps, walked along transects and searched under stones to count the available prey items – lizards and invertebrates mostly.

We found that available prey in the preferred patches was twice as high as in the surrounding areas which would explain why the birds favoured them. We also found that available prey declined during the breeding season which may help explain why the birds migrate away from the breeding site so early in the year (July). In spite of this decline, the preferred patches remained richer in food compared with surrounding areas. Interestingly, the prey levels were lower near the nesting site, which explains why the birds undertook long commutes from their nests to forage for food elsewhere.

Implications

This work highlights the vulnerability of the birds at this site. Degradation of the patches they use could reduce food supply below critical levels and alternative sites may be hard for the birds to find since they are relatively scarce. The birds are also vulnerable to a shortening of the season in which adequate food is available which could result from a changing climate. There is already little time after the chicks fledge for them to prepare for the long migration to southern Saudi Arabia and Ethiopia. Low food availability in mid summer makes the birds dependent on sites around local reservoirs for food and these have dried up recently. Breeding failures in 2008 and 2009 may have been mitigated by improved feeding conditions on the breeding area.

Recommendations

The successful management of the site for ibises should ensure full protection of the preferred feeding areas, measures to improve their food security through improved range management, and possibly reservoir rehabilitation.