What is happening with the Mack Øst kittiwakes?

In early May, we published an article on the kittiwake hotels in Tromsø, highlighting the Mack Øst case as an example of thoughtful and effective management.

Thanks to the ongoing efforts of the Kittiwalkers, who closely monitor the nests on Tromsøya, we’re now able to report on what was once one of Tromsø’s largest urban colonies.

A Kittiwalker surveys the "Mack Øst" kittiwake hotel in June 2025.

The demolition

Early 2025, the Mack Øst building was torn down. About 150 pairs of kittiwakes had established their nest on the roof and window sills of the massive building. The demolition was the early stage of a project that will lead to the construction of an entire new neiborhood that will include a museum, a concert hall, appartments, hotels and restaurants.

The Mack Øst building during the demolition in March 2025.

A preventive and compensatory measure

To reduce the risk of the birds dispersing and to compensate for the loss of their former colony, two kittiwake hotels were erected on the site. This compensatory measure was a condition for the demolition to proceed.

One of the two kittiwake hotels on the Mack Øst demolition site in April 2025.

A promising start

Soon after the installation of the hotels, the displaced kittiwakes adopted these structures that resemble traditional fishdrying racks. These hotels are designed to accommodate all the pairs that once nested on the Mack Øst building. Although it was still early in the season for nest-building, the birds showed clear interest in the alternative site, despite the loud noise from nearby demolition work.

Kittiwakes on the Mack Øst hotels the 3d of May 2025.

Unfortunate desertion

After the fences were rearranged to reopen pedestrian access along the shoreline—creating a shortcut from Nestranda to Polaria—the kittiwakes abandoned the hotels. While the noise from heavy machinery hadn’t appeared to disturb them, the steady flow of people, bicycles, and dogs passing nearby proved incompatible with their presence. Kittiwalkers monitoring the site noted signs of stress, with birds frequently taking off or displaying restless behavior in response to the proximity of passersby. This may seem surprising, as kittiwakes elsewhere often nest close to people. However, the hotels are low in height, and the birds at this site had not been habituated to such conditions, nor did they have enough time to adapt.

Desterted Mack Øst kittiwake hotel after the fence has been moved to allow people to follow the waterline.

Emergency measure

When we understood the impact of the situation, we raised our concerns with those who had been in direct contact with the contractor and recommended placing a fence at a reasonable distance from the hotels. This, we hoped, would allow kittiwakes to return while still letting people move freely along the waterfront. After several weeks without response, we took the initiative one windy Sunday morning to install a temporary barrier using barrels and rope. Almost immediately, the kittiwakes returned, and the hotels were once again filled with their calls.

Kittiwalkers are monitoring these hotels nearly every day. Recent counts of the two hotels combined have been fairly consistent, with around a hundred adults present and 10 to 15 active nests, defined as nests currently attended by an incubating adult. These observations suggest that the seaside wall of the Mack Øst hotels is attractive to the kittiwakes. In that sense, the operation is a success. However, the late installation of the structures, followed by a period of abandonment and then return, might still impact the overall breeding success at this alternative site.

The temporary fence made of rope and water-filled barrels at the Mack Øst kittiwake hotels in June 2025.

Kittiwakes on the Mack Øst building

Around one hundred adult kittiwakes and approximately 15 active nests are recorded on the building almost daily by various Kittiwalkers, with consistent counts regardless of the observer. The presence of active nests is particularly concerning in the short term, as it is not permitted by law to disturb breeding kittiwakes.

We have been informed by a reliable source that the contractor intends to install wooden boards between the nests and the building’s interior. If carried out with care and consideration, this measure could allow both the birds and the construction team to coexist without conflict until the last chick has fledged.

Kittiwakes on the Mack Øst building in June 2025.

From a legal standpoint, it is not allowed to disturb kittiwakes during the nesting season.

From a conservation standpoint, the urgency is even greater. As the kittiwake is classified as Highly Endangered on Norway’s Red List ("Sterkt truet" in Norwegian) safeguarding each breeding pair and their chance to raise chicks is vital to the species' future survival in Norway.