The harvesting of Onion Grass (Romulea rosea) corms by flocks of Sulphur‐crested Cockatoo (Cacatua galerita) is well known. Individual birds and large flocks feed on the weed in pastures, grasslands and recreational turf. Flocks of Sulphur‐crested Cockatoo were observed feeding on Onion Grass at seven sites along the Maribyrnong River at Keilor, Victoria. Flock size and feeding habits were noted, as were the depth of corms, the time taken to remove corms from the ground and the number of eaten and lifted but uneaten corms. From the data collected, it was estimated that an individual bird can extract and eat about 200 plants per hour and that even a small flock can consume several thousand plants in a feeding session. Corms were typically within 20 mm of the soil surface and were removed primarily by the cockatoo with its beak, but the left foot was sometimes used to excavate the corm from the soil. Flock feeding sessions lasted from about 0.5 to 2.5 hours, but feeding by individual or pairs of birds was often shorter. Plants that had been removed from the soil appeared to have intact corms, but all that was left were the outer scales. Of the plants removed from the soil, only 6% had intact corms attached. The removal of large numbers of Onion Grass plants could impact on their population numbers over time if there was repeated annual harvesting.

中文翻译：

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硫凤头鹦鹉（Cacatua galerita Latham）收获凤头鹦鹉Romulea rosea L.

硫凤头鹦鹉（Cacatua galerita）成群的洋葱草（Romulea rosea）球茎的收获）是众所周知的。个别鸟类和大群人以草，草和休闲草皮为食。在维多利亚州基勒的马里比农河沿岸的七个地点，观察到一群硫磺凤头鹦鹉以洋葱草为食。记录了鸡群的大小和喂养习惯，以及球茎的深度，从地面去除球茎所需的时间以及被食用和提起但未吃掉的球茎的数量。根据收集到的数据，估计每只鸟每小时可以提取和食用约200株植物，即使是一小群鸡，在饲喂过程中也可能消耗数千株植物。球茎通常在土壤表面的20毫米之内，主要是通过凤头鹦鹉的喙将其除去，但是有时用左脚从土壤中挖出球茎。鸡群喂食时间从大约0.5持续到2。5小时，但通常以个人或成对鸟为食的时间较短。从土壤中移出的植物似乎具有完整的球茎，但剩下的只是外表。从土壤中移出的植物中，只有6％附着了完整的球茎。如果每年重复收获，大量洋葱草的去除会随着时间的流逝而影响种群数量。