He concluded that differential bird predation was a major factor responsible for the decline in carbonaria frequency compared to typica in Cambridge during the study period, and described his results as a complete vindication of the peppered moth story.
Concluíu que a predación diferencial das aves era un factor principal responsable do declive da frecuencia do morfo carbonaria comparado con typica en Cambridge durante o período de estudo, e describiu os seus resultados como unha completa vindicación da historia da Biston betularia.