The objective of this study was to evaluate the effect of food supply in garbage dumps on the reproductive fitness of Cattle Egret Bubulcus ibis and offspring losses. A total of 236 nests were monitored during two distinct periods of 2 years for each: 146 nests during a period without food supply in dumps (1998–1999) and 90 with food supply in dumps (2007–2008). The study was carried out in the colony of El-Kseur in the Lower Soummam Valley (northeast Algeria). For the entire study period, the mean of clutch size, average number of hatched chicks, productivity, and breeding success varied significantly between years (Kruskal–Wallis test: p < .05). Also, the average calculated losses for eggs, chicks, and total offspring vary significantly (Chi2 test: p > .0001). The clutch size and the number of hatched chicks per nest were highest during the period with food supply in garbage dump (respectively: 3.46 ± 0.86; 2.85 ± 1.11), compared to the period when cattle egrets feed in natural or agricultural habitats (3.04 ± 0.87; 2.54 ± 1.03). However, productivity and breeding success were highest during the period without food supply (respectively: 2.11 ± 1.16 fledging’s/nest; 0.70 ± 0.35) than in the period with food supply (1.14 ± 0.91; 0.35 ± 0.30). While egg losses were substantially similar between the two study periods, chick’s mortality (59.9%) and total offspring losses (36.7%) were higher during the period with food supply. The generalized linear mixed model (GLMM) analysis indicated a large negative effect of food supply in dumps on the productivity, on the chick’s losses; and a positive effect on the total offspring losses (p < .001). Also, feed in dump garbage revealed a significant negative effect on the breeding success linear mixed model (LMM, p = .01). However, no significant effects (GLMM, p > .05) of food supply in dumps were noted on average clutch size, the mean number of hatched chicks per nest, and egg losses.

本研究的目的是评估垃圾场食物供应对牛背鹭Bubulcus ibis繁殖适应性和后代损失的影响。在每个 2 年的两个不同时期内，总共监测了 236 个巢穴：在垃圾场没有食物供应的时期（1998-1999 年）有 146 个巢穴，在垃圾场有食物供应的时期有 90 个巢穴（2007-2008 年）。该研究是在下苏曼河谷（阿尔及利亚东北部）的 El-Kseur 殖民地进行的。在整个研究期间，离合器大小的平均值、孵化小鸡的平均数量、生产力和繁殖成功率在不同年份之间存在显着差异（Kruskal-Wallis 检验：p < .05）。此外，鸡蛋、雏鸡和总后代的平均计算损失差异很大（Chi2 检验：p> .0001)。与牛背鹭在自然或农业栖息地觅食的时期相比，在垃圾场提供食物的时期（分别为：3.46 ± 0.86；2.85 ± 1.11），离合器大小和每窝孵化的小鸡数量最高（3.04 ± 0.87；2.54 ± 1.03)。然而，在没有食物供应期间，生产力和繁殖成功率最高（分别为：2.11 ± 1.16 雏鸟/巢；0.70 ± 0.35）高于有食物供应期间（1.14 ± 0.91；0.35 ± 0.30）。虽然两个研究期间的卵子损失基本相似，但在食物供应期间，雏鸡死亡率（59.9%）和总后代损失（36.7%）更高。广义线性混合模型 (GLMM) 分析表明，垃圾场的食物供应对生产力和雏鸡损失有很大的负面影响；p < .001)。此外，垃圾中的饲料对养殖成功线性混合模型有显着的负面影响（LMM，p = .01）。然而，没有发现垃圾场食物供应对平均鸡窝大小、每个巢穴的平均孵化小鸡数量和鸡蛋损失有显着影响 (GLMM, p > .05)。