Complex sentence: The experts begin to build artificial nests to attract Rosy Starlings, an effort reported to be so successful that the number of locusts was insufficient to feed the birds, causing many juveniles die for hunger.
Split into simpler sentences: The experts begin to build artificial nests to attract Rosy Starling. The plan is greatly successful that, the number of locust is insufficient to feed the birds, that many juveniles die for hunger.