Now a new study suggests that sex reversal could be more common in birds than we thought, showing that a population of nearly 500 birds containing five species contained a sex reversal rate of around 5 percent. One of the more drastic examples is a biological process known as “sex reversal,” when a species’ genetic sex doesn’t match its observable characteristics, otherwise known as its phenotype. fish, reptiles, amphibians), sex reversal can be a response to temperature, environmental pressures, or a strategy to extend reproduction. Across the 480 specimens, the researchers found 24 cases where birds displayed sex reversal. Only 3 percent of Australian magpies (Gymnorhina tibicen), for example, displayed sex reversal characteristics, while crested pigeons (Cyphaps lophotes)—which have the most amazing little mohawks and mating rituals —had sex reversal rate of 6.3 percent.