Common cranes hatched two baby chicks earlier this year, the first recorded birth of crane chicks in Ireland in over 300 years.
The cranes set up home on a rewetted peatland earlier this year, according to Bord na Móna.
Mark McCorry, lead ecologist at Bord na Móna, has said that cranes have largely disappeared from Ireland due to hunting and loss of habitat over the past 100 years.
One of the chicks, which hatched in May, disappeared shortly after it was first seen. The second chick was not seen since late June - possibly because it went missing or it might have been predated.
Bord na Móna ecologists believe there is still a chance that the chick may have survived and fledged. However, it is believed to be more likely that a predator may have carried off the young bird, or that it died for some other reason.
Speaking on RTÉ's News at One, Mr McCorry said that a range of "pressures" on the wetlands bird have led to their disappearance.
He said: "A lot of our wetlands have been reclaimed for agriculture over the past few 100 years so there was a lot of loss of habitat. Unfortunately, the crane was also hunted for food and actually hunted for feathers as well."
"So there have been pressures on the species, and that's why they disappeared."
Mr McCorry said the species has been successfully reintroduced in Britain, and in several other countries in Europe.