flooding decreases the availability of food & a living thing requires food for survival ->  flooding can decrease the availability of food required by living things for survival  flooding can decrease the availability of food required by living things for survival & a parrot is a kind of living thing ->  flooding can decrease the availability of food required by parrots for survival  the decrease of something required by an organism has a negative impact on that organism 's survival & a parrot is a kind of organism ->  the decrease of something required by a parrot has a negative impact on that parrot's survival  flooding can decrease the availability of food required by parrots for survival & the decrease of something required by a parrot has a negative impact on that parrot's survival -> flooding decreasing food availability has a negative impact on parrots survival