It's the first time young of the species have been hatched in the zoo's 142-year history, the Chicago Tribune reported.
The hatchlings will live in full view of humans in a large nest within sight, WBBM-AM, Chicago, said Saturday.
Not to be outdone, a pair of rare of Cinereous vultures sharing the habitat of white storks also welcomed their own hatchling, not having raised a chick since 2002, WBBM said.
"The Bird Department and Lincoln Park Zoo are very excited about this unprecedented event. Both of these species are hatched and reared in accredited zoos infrequently. Having both is quite an accomplishment," said Colleen Lynch, Curator of Birds.
"The stork and vulture parents are all doing great jobs of tending their chicks and we expect that they will continue to do so as the chicks grow up over the summer," she said.
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UPI Almanac for Sunday, Sept. 21, 2014