Record number of Cahow breeding pairs
Bermuda’s national bird continues to set records after scientists reported a new high number of 142 established breeding pairs, up from 135 pairs in 2020.
The number of Cahow pairs on the nature reserve of Nonsuch Island has increased to 27 this year, with 13 chicks – one of which is this year’s CahowCam 2 chick.
Jeremy Madeiros, principal scientist with the Department of Environment and Natural Resources, said 2021 had tied with the previous record of 13 fledged Nonsuch chicks in 2018.
He added there were “perhaps the highest recorded annual number” of at least 14 newly-established pairs that will likely have their first eggs next season.
“Nine of these new prospecting pairs are in the two new nesting colonies on Nonsuch island, which only produced their first fledged chick in 2009.”
Chicks of the endangered seabirds, painstakingly brought back from the brink of extinction, are now half-fledged, at six to seven weeks.
Nonsuch, at the southern end of Castle Harbour, was originally a historic nesting location for the Cahow.
The birds were wiped out on the island through hunting and by the introduction of pests such as rats.
Near-fledged chicks were moved to artificial burrows during two projects on Nonsuch from 2004 to 2008, and 2013 to 2017.
After leaving to spend three to six years at sea, most of the Cahow returned to Nonsuch, with the first pairing up on the island in 2009 to produce the first naturally hatched chick recorded on Nonsuch Island for almost 390 years.
Mr Madeiros said: “Since this first chick, the new Cahow colonies on Nonsuch have increased from one pair in 2009 to 30 breeding pairs producing eggs in the 2021 nesting season.
“The number of successfully fledged chicks produced by these new Nonsuch colonies also increased from 1 to 89 chicks by 2020.
“If all 13 of this year’s crop of Nonsuch chicks fledge successfully in late May and June, then these colonies will have reached a significant milestone in having produced a total of 102 fledged chicks.”
Of every ten birds that heads out to sea, only three or four survive to return and pair up with a partner, usually for life.
Mr Madeiros said there were at least 71 chicks in burrows on all the nesting islands – just below 2019’s record number of 73 successfully fledged chicks.
You can learn more about the cahow at www.nonsuchisland.com