Increasing threats to animal migration

Published on: 13. October 2021
Author: Anne Olga Syverhuset

The advantages for animals migrating to northern breeding grounds are being eroded, as the animals experience lower food availability, higher pathogen pressure and increased predation rates.

Increasing threats to animal migration
The dunlin (Calidris alpina) is a small, migratory wader. Photo: Brett Sandercock / NINA.

Every year, millions of wild animals undertake long-distance migration to breed in the north. Migration is both dangerous and resource demanding, but the advantages outweigh the disadvantages. High food availability and long days for foraging in the summer, lower pathogen and parasite pressure and fewer predators represent major benefits, making the risk worthwhile. However, the advantages of migrating to northern latitudes are decreasing.

“Animals in the northern regions are experiencing changes in food supply related to climate change, and diseases and parasites are spreading north, as well as predators”, says Brett Sandercock, senior scientist in the Norwegian institute for nature research (NINA).

In collaboration with colleagues from The Czech Republic, Hungary and Great Britain, the international team have summarized research on a broad spectrum of migrating animals. The research has been published as a new article “Animal migration to northern latitudes: environmental changes and increasing threats” in “Trends in Ecology & Evolution”.

Hungry bears and tiny microbes threaten the common eider

The common eider is one of the species facing difficulties on their migrations for their northern breeding grounds, such as Svalbard.  Polar bears have a harder time hunting seals due to the decreasing sea ice, and instead turn to the nests of common eider and other colonial species for food.

In Arctic regions of Canada, the common eider is facing yet another large – and tiny – challenge. Climate changes have opened up new areas in the north for pathogens and parasites, and recent outbreaks of avian cholera have killed large numbers of birds in some colonies.

Disturbances in the “undisturbed” north 

Changes along the migratory routes, especially land use changes and anthropogenic disturbances, have received most attention as explanations for the decline in numbers of many populations of migratory animals.

“Changes in the northern regions have received less attention, as these regions are often seen as large, undisturbed regions. There are, however, many changes occurring in these more remote areas", Sandercock says.

Both acute and long-term stressors affect migrating animals

“The spatial and temporal extent of the changes are important factors in order to be able to forecast the effect of the changes”, says Sandercock.
Disturbances, such as storms, or a temporary mismatch in the timing of food resources, can be relatively brief, acute stressors that do not necessarily affect the animals over the long term. If repeated, however, such acute events can turn into long-term stressors. In Alaska, for example, the insects that the sandpipers rely on for food emerge six days too early, on average, resulting in food shortages when young birds need the food the most. Another example is the wild reindeer at Svalbard. Rain on snow events during the winter result in a layer of ice covering the vegetation, making it inaccessible for the reindeer.

Long-term, chronic stressors, such as temperature increase or an increase in woody plants, are slow, gradual changes over several decades. When such changes reach an ecological threshold, the whole ecosystem might shift to such an extent that it is no longer suitable for some of the species using the areas.

Need for international solutions

It will be challenging to directly mitigate the large-scale impacts of climate change for migratory species that are dependent on multiple environments distributed across several regions of the globe. Conservation efforts both on small and large scales are necessary, from local nest protection to development of networks of protected areas.

“It is important to consider the cumulative effects of all the different factors in different areas, and international solutions  are necessary to mitigate the negative effects”, says Sandercock.

Brett Sandercock (NINA)
Lead author Vojtech Kubelka


Kittiwakes find refuge on offshore oil rigs

Offshore oil rigs serve as a breeding refuge for Norwegian Black-legged Kittiwakes. Although they are few in number, these birds produce more chicks than kittiwakes in natural colonies along the coast, to the benefit of the impoverished Norwegian Kittiwake population. ...
Read more..

Seabird experts in CAFF propose a new kittiwake conservation plan

The Circumpolar Seabird Group under CAFF and the Arctic Council has proposed a conservation plan for the black-legged kittiwake Rissa tridactyla , a species which has been declining severely since the 1970s. Four main objectives are identified, and specific action...
Read more..

Palm oil certification brings mixed outcomes to neighbouring communities

Sustainable certification of oil palm plantations can reduce poverty, but the timing of certification is among the factors that influence the effect.
Read more..

Seabirds and kelp harvest – conflict or harmony?

Foraging shags and commercial kelp harvesters very often utilize the same marine areas.
Read more..

How efficient are mitigation measures for bird-friendly wind power?

Simple measures can make wind turbines more bird friendly. New research shows that measures such as painting the rotor blades or towers, using UV-light and smart micro-siting of wind turbines, decreases the risk for bird collisions considerably.
Read more..

Wild salmon’s wild journey in the ocean

Last spring Atlantic salmon were tagged with satellite tags in Southern Norway. Now they have phoned home.
Read more..

Vultures respond to auditory cues

Vultures and other avian scavengers characteristically circle the skies, scanning the ground for carcasses. New research has revealed that these birds can, in addition to sight, respond to auditory cues indicative of potential foraging opportunities.
Read more..

Carbon emissions have made the world a greener place, which has a cooling effect

The very same carbon emissions responsible for harmful changes to climate are also fertilizing plant growth, which in turn is somewhat moderating global warming. This affects also remote places, like the High Arctic.
Read more..

Animals take climate action

Migratory animals are actively adjusting their traditions to climate change.
Read more..

A ray of hope for the golden deer of Myanmar

Developing state-of-the-art statistical tools that combine different sources of data has allowed researchers from Norway and Myanmar to make robust estimates of population size for an often-overlooked population of one of the world’s most threatened deer species. The r...
Read more..

Have you checked your baggage for alien species?

Are you travelling to the Arctic? Seeds, insects and parasites can travel with you as stowaways without your knowledge. A new short film explains how you can avoid bringing unwanted species that can threaten the vulnerable Arctic environment.  
Read more..

China and India dominate in greening the Earth

A new study reports China’s planting of trees and India’s intensive crop cultivation as the main reasons why the Earth is greening throwing doubt on the role of carbon dioxide fertilization, which climate change skeptics have touted as the beneficial effects of otherwi...
Read more..

First estimates of body mass change between the breeding and wintering stage in Atlantic Puffins.

By measuring body mass and wing length of adult Atlantic Puffins on their breeding grounds and in their wintering areas near the Faroe Islands, researchers have now estimated the seasonal changes in body mass for two populations breeding in Norway and Scotland.
Read more..

Long-term side-effects of abdominal implants in brown bears

A recent study from the Scandinavian Brown Bear Research Project has shown serious side effects from radio transmitters implanted into the abdominal cavity of brown bears.
Read more..

Environmental benefits of leaving offshore infrastructure in the ocean

More than 7500 oil and gas platforms and wind turbines will become obsolete in the next few decades. Full removal may not be the best plan after all, according to new survey of international experts.
Read more..

Standardization and facilitation of seabird data for use in impact and environmental risk assessments

A new NINA-report gives recommendation on how seabird data should best be used in impact and environmental risk assessments.
Read more..

NINA Annual Report 2017

NINA’s key statistics and activities throughout 2017. 
Read more..

Flexibility in the foraging behaviour of the kittiwake may buffer the effect of marine environmental changes

Recent Norwegian research shows that the black-legged kittiwake is surprisingly flexible when it comes to finding food for itself and its chicks. The ability to adapt makes this small gull robust to changes in the marine environment – that is, if it has access to suita...
Read more..

Impacts of salmon lice on wild Atlantic salmon and sea trout

New report concludes: Considerable evidence exists that there is a link between farm-intensive areas and the spread of salmon lice to wild Atlantic salmon and sea trout. 
Read more..


Norwegian Institute for Nature Research

NINA is an independent foundation for nature research and research on the interaction between human society, natural resources and biodiversity.
Follow us on: