Résumé:
The ecology of two dabbling ducks: Northern Shoveler Anas clypeata and Mallard
Anas platyrhynchos and Greater Flamingo Phoenicopterus roseus were investigated at El
Eulma wetlands complex in the eastern Hauts plateaux northeast, Algeria during the period
2007-2010.
Fluctuations and a sharp decline were recorded in the number of Northern Shoveler
population at two study sites. S.Bazer, however, showed to be the most frequented site over
the study period. The maximal counts increased by two fold within 2008 and 2009. Analysis
of diurnal time budgets showed that sleeping was the dominant diurnal activity at S.Bazer
where birds devoted almost 1/2 to 3/4 of their mean percentage time spent to sleeping (47 %
in 2008/09, 68 % in 2009/10). Sleeping was, however, the second diurnal activity at S.El
Hamiet with a mean value of less than 1/2 of the time allocated. The seasonal evolution in
mean percentage time apportioned to sleeping showed slight fluctuations at both study sites
with a domination of sleeping at S. Bazer over winter 2009/10, while feeding exhibited a
similarity between sites and a difference in pattern between years. Feeding was accomplished
in three ways: surface feeding, dabbling and grazing with flexibility in using the former and
the second foraging methods. Swimming showed similarities between sites and differences
between years with mean values < 13%. Resting, preening and locomotion accounted for <
6%; whereas, flying, agonistic behaviour and courtship were rare. Hourly data analysis
showed that time spent feeding was concentrated on edge hours with some alterations.
Feeding and sleeping as two main activities were quite similar between sites and unlike
between years when expressed in hours.
The phenology of Mallard indicates that the first winter visitors arrive in early
September, reach a large size between late September and early October, disperse in mid
winter and occupy the sites during breeding season till early summer. Mallard population
frequenting mainly S. Bazer exhibited stability over the three year observations and a high
attraction to this site.The dominant behaviour of the diurnal activity time budget of Mallard
was sleeping and resting and accounts for 89% of the diurnal time spent within the wintering
period. Results on mean percentage time spent feeding (3%) by Mallard were similar to that
of Camargue, South France. Mallard shows a great flexibility in foraging methods with
dominance of dabbling.
The results indicated clearly that El Eulma wetlands complex is one of the important
wetlands zones in sheltering, wintering and aestivating population of Greater Flamingo and a
breeding ground. The higher number of Greater Flamingo counted during spring and summer
seasons at S.Bazer over 2007-2010 confirm previous studies in Algeria. S. Bazer considered
as a stopover and wintering quarter for migratory birds is the third breeding site after Ezzmoul
in the Oum El Bouaghi wetlands complex and El Golea in the Algerian Sahara. The use of
artificial nests to encourage breeding at S. Bazer seemed to induce Greater Flamingo to built
300 new nests and started an attempt at incubation in the middle of the dried salt lake before
deserting the colony in mid August 2010.
Thus the present study emphasizes the ornithological values of the wetlands Complex
of El Eulma and suggests the urgent need for better management and protection of these
valuable wetlands from continuous deterioration.
