Breeding Success of the Cattle Egrets, Bubulcus Ibis L. in the Arid Zone of Northeastern Nigeria
* Sharah1 H.A., Buahin2 G.K.A., 2 and Sastawa3 B.M.
1Director, Planning, Research and Statistics, Ministry of Agriculture and Natural Resources, P. O. Box 1604, Maiduguri, Borno State, Nigeria. (P.M.B. 1047, Maiduguri, Nigeria). 2
Department of Biological Science, University of Maiduguri, Nigeria.
3Department of Crop Protection, University of Maiduguri, Nigeria.
* Corresponding Author. E-mail: firstname.lastname@example.org
Accepted on September 10, 2007
The breeding success of cattle egrets, Bubulcus ibis L, was monitored over four years, where 1992 and 1993 were preliminary surveys, demarcations, and surveillance, and 2002 and 2003 were actual observations and data capture. The ten year lapse was purposeful, to determine the permanency of the sites, because cattle egrets constantly change breeding sites every two to three years, due to death of colony trees. Mbodewa, Jebra and Konduga were the three permanent breeding sites, located in the Sahel and Sudan Savannah Zone of Northeastern Nigeria, where the birds had nested for over twenty years. These birds are the popular and conspicuously snow-white terrestrial foragers both in feeding behaviour and habits, feeding entirely on animals (99.1%) and removes insect pests (88.4% ) from the farmers field making them useful to agriculture in these zones. They have buff coloured plumes on the crown, breast and back during breeding periods. This study therefore, wishes to prove whether environment can affect hatching success and whether egg parameters can affect breeding success. The knowledge of the above will help provide the people of the zones with knowledge of the breeding and feeding behaviours of these birds, their importance to the environment and also to encourage conservation and security of the birds. Double lens, 10 × 50mm Pilkington binoculars were used for field observations, Funki M7383 Model incubators, 512 egg capacity was used for artificial incubation, colour chart ++512 was used in egg-colour comparison and Double barren shot gun was used to obtain birds for diet study. One to four (X = 2.5), light blue (++ 512 colour chart) oval, round to elongated eggs in shape, were laid in the middle of the round to boat –shaped nests at full clutch. Mean hatching success was 80% in all sites within the first 25 days of incubation period and 71.3% chicks became independent young adults in 50 ±6days after hatching. Mean breeding birds populations and Nest numbers varied with site and month, (0 = 1375 and 0 =271) in May and increased by 79% in September, but declined by 33.6% in November as parents abandoned nests sites after chicks fledged. Heronry abandonment left the sites with many dead and defoliated trees, the ground underneath were littered with dead eggs shells, carcasses and nesting materials causing environmental degradation around nest colony sites. Before total nest sites abandonment, juveniles creched together every evening for two weeks in similar age groups. Breeding success was directly correlated to hatching and fledging success as discussed in the text.