The news that Nigel had been found dead alongside one particular concrete bird suggests that he believed it was his partner in life, the Daily Mail reported.
The solitary gannet had given hope to conservationists after he settled on Mana Island five years ago, lured by the concrete colony he thought were real.
Despite his ability to bond with the birds, no others followed him...until Christmas Even last year, when three new gannets arrive.
However, the jubilation for a potential new generation was cut short, when Nigel was found dead.
The Friends of Mana Island Facebook group was first to report the death, saying: 'Some sad news from the island... Nigel our first gannet has died suddenly.
"Nigel won the hearts of Friends of Mana Island members and visitors to the island, settling there alone."
A poem penned in honour of Nigel, the gannet:
To Nigel
You stayed awhile on Mana Island,
Attracted by your concrete...
Posted by Friends of Mana Island on Wednesday, 31 January 2018
The news of Nigel's death went international with The New York Times paying tribute to the "world's lonelist seabird".
"Footage of the bird preening and cooing as he fruitlessly courted a decoy made of concrete has been watched obsessively online. Though his chosen partner kept a cold silence, Nigel, a gannet, won the hearts of visitors and conservationists alike," they wrote.
"He quickly took a liking to one of the concrete replicas... Month after month, the bird cozied up to his chosen mate, but she maintained an aloof presence.
"But his solitary life also shined a light on a yearslong effort by an army of conservationists, devoted volunteers and others to repopulate his species on the island.
"News of the seabird's death in late January hit the island's caretakers."
On social media, response to Nigel's passing saw thousands of people express their sadness with poems and photos shared about the lonesome gannet.
@ReetuKabra wrote: "I never thought a story about an isolated New Zealand bird would break my heart but it has. No point making any more plans for Nigel."
@AnnCaito1 added: "So, so sad. Why couldn't he have been placed with others? Why leave him alone? Having a decoy just set him up 4 loneliness and kept him from seeking true mates. Mortifyingly sad.'"
After reading an article on the gannet's death, @holland_tom penned: "Pretty much every line in this report on a gannet who lived alone for years among concrete gannets tears at the heart."
Many others simply shared memes and gifs of people crying.
The conservationists at Mana Island even wrote a poem, published on their Facebook page. It read:
"To Nigel You stayed awhile on Mana Island,
Attracted by your concrete mates
You built a nest, you did your best
But only Norman dropped on by.
We weeded, we painted, we sprayed guano around.
We hoped you'd find the real thing.
Three newbies arrived, a Christmas surprise.
But suddenly you are gone.
RIP 'no mates' Nigel"