It is hoped the birds will return in 2010
Bird experts said the severe winter may explain why a rare bird of prey did not nest in Northumberland.
It was hoped that 2009 would be the fourth year of hen harriers breeding in the area.
A 24-hour nest guard with a team of volunteers had been ready but despite a male and female bird being seen earlier in the year, they did not make a nest.
The RSPB said the cold winter, which meant there was less prey around, may have been a factor.
RSPB conservation officer Gill Flint said: "It seems to reflect the situation that has happened across the country. It seems to have been quite an unusual year.
"It's difficult to pinpoint any particular reason. One of the ideas is that it was a really cold winter which means there was less prey available for the birds.
"Therefore the male may not have been able to get enough food in the display period or the female may have been not getting enough food to get into her breeding condition."
She said there was a lot of disappointment among those involved in the project but there were hopes the birds would return to breed in 2010.
In 2008, five female chicks fledged from the North Tynedale nest.
In December, Natural England said hen harriers were nearing extinction in England because of illegal persecution.