The newest Cincinnati Zoo residents have reached a big milestone!After the birth of African penguin chicks for the first time in three years at the zoo, the zoo shared a video of the chicks taking their very first swim, and diving in without hesitation! See the video in the player above."Watching them paddle, splash and test out their waterproof feathers for the first time is a moment we won't forget," the zoo posted on its Facebook page. "They're growing up fast!"The birth of the chicks is marking a hopeful milestone for a species at risk of extinction."They are critically endangered, and they're a species that the again, our since I zoo was getting engaged in and collaborating with our colleagues in South Africa," Cincinnati Zoo director Dave Jenike told sister station WLWT last month.Jenike, who has been with the zoo for more than 35 years, is leading efforts to engage and collaborate with colleagues in South Africa to protect the critically endangered penguins.