The University of Cambridge has apologised “unreservedly” on Twitter following a dispute over netting placed over trees to stop birds nesting in them.

The nets received severe criticism from Chris Packham, a conservationist and TV presenter. He tweeted on Thursday to express his anger and frustration, describing the netting as “absolutely outrageous”.

Extinction Rebellion also took issue with the nets. On Thursday night, a group of activists cut and removed them from the trees. They cited the threat habitat destruction poses to British birds and demanded that the practice of netting “must end”.

The activists also claim to have found one tree which had been filled with foam to prevent birds nesting in its holes.

It comes following the week-long series of protests and blockades by the group which were, in part, targeted at the University and its connections to fossil fuel industries.

The nets were put up on around twenty trees on Wednesday at the West Cambridge site. The University said that they were concerned that nesting birds would be disturbed by construction work to expand the Whittle Laboratory. This work requires that the trees at issue be replaced or moved.

It is illegal to disturb birds once they have settled in a tree as it becomes a protected site. Birds nesting now would not leave until the summer, potentially delaying building work by six months.

Methods to prevent birds nesting in the first place, such as netting, are legal.

However, conservationists have long expressed concern about such techniques. Martin Fowlie, from the RSPB, said the University’s decision was “morally dubious”.

Jeff Knott, operations director for Central and Eastern England at the RSPB, told Cambridgeshire Live the decision to install the nets was “ludicrous”: “We can’t keep painting nature into smaller and smaller spaces.”

The organisation has been calling for tighter controls on netting since last year, expressing concern about habitat loss and the risk of birds getting trapped in loose netting. 43% of British bird species are classified as ‘threatened’ under the IUCN Red List. Another 10% are ‘near threatened’.

The University initially promised that the “netting will be checked for wildlife three times a day”, but under continuing pressure, they decided to remove them.

In the wake of the decision to remove the netting, the University wrote on Facebook that they “will be consulting with experts on our local trees and wildlife before any further activities related to these trees is [sic] carried out”.

It is unclear if there will be any effect to the building work on the West Cambridge site or if the foam has been removed from the trees.

Varsity has reached out to the University for further comment.