Drones are flying to the approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version of tortoises in the USA's Mojave Desert. Tortoises in the Mojave are under approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version of being wiped out by ravens. The raven is a bigger approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version of the crow. The raven approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version in the Mojave has increased by 700 per cent in the approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version 25 years. This has had a approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version impact on the desert tortoises. A local conservationist said that in some approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version , "where there used to be 10 ravens, there are now 15,000". If approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version is done to help the tortoises, they could be approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version wiped out. Their approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version have fallen by over 90 per cent since 1990. Technology may rescue the tortoises. Biologists and drone approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version have a strategy to reduce the raven approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version . They are using drones with a approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version called "egg oiling". This involves flying drones up to ravens' nests, removing approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version eggs, coating them with corn oil, and then replacing approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version . The oil blocks oxygen from entering the egg, thus ending the life of the approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version inside. A biologist said: "If ravens figure out that their approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version are rotten, they are approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version to...nest someplace else." A conservationist said egg oiling was justified as " approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version of a comprehensive approach catastrophic completely defence eggs embryo fertilized likely nothing numbers operators part past places population technique them threat version ".