Increased temperatures in the Arctic due to climate change are causing earlier and earlier springs and negatively affecting the migratory birds that go to the Arctic to breed.
A new study found that even though migratory barnacle geese have tried to adapt to the earlier arctic springs by speeding up their 3,000-kilometer migration and taking fewer stops along the way, the birds are still laying their eggs too late.
Because the geese are speeding up their travel time to get to the Arctic breeding grounds quicker, they need more time to rest and refuel before laying eggs. This has led to the reduced survival rate of goose chicks.
The chicks are not able to forage properly or survive long to migrate on their own.
Researchers from the Netherlands Institute of Ecology and the University of Amsterdam used a combination of tracking and observational methods to follow barnacle geese as they traveled to their Arctic breeding grounds in order to see how climate change was impacting breeding times and migration.
Every spring, barnacle geese travel from temperate wintering grounds along the North Sea to breeding grounds in the Russian Arctic.
The researchers observed that during early springs in the Arctic, the geese who had tired themselves during their migration didn’t lay their eggs until after the snow started melting. This created a disparity between hatching times and peak food availability.
The results were published in the journal Current Biology and show that unless migratory birds can learn to leave earlier as opposed to simply speeding up their travel time, geese populations could steadily decline.
One problem is that the geese are sensitive to certain cues that signify it’s time to make their migratory trek such as a change in day length and vegetation greening, however these do not necessarily warn of warming temperatures in the Arctic.
“The birds are leaping in the dark as they cannot predict, while being at the wintering grounds in temperate areas, whether it is going to be an early or late spring in the Arctic,” said Bart Nolet, a co-author of the study.
“The weather systems in the temperate and Arctic regions are not linked, and on top of that, temperature rise is far stronger in the Arctic than in the temperate region. Only halfway through the migration, the geese are probably able to judge from environmental cues what spring will be like up in the Arctic, and they are apparently able to speed up if spring is early.”
The researchers say that the only hope for the birds lies in their ability to adapt to climate change and migrate earlier.
There are instances of some barnacle geese making major adjustments to their migration patterns but it remains unknown whether or not if barnacle geese as a whole can change their migration cues.
“Geese migrate in families, and young learn the route and timing from their parents,” said Nolet. “On the one hand, this leads to traditional patterns; on the other hand, it can lead to rapid adjustments when some birds experience that doing the migration differently–often induced by extreme weather events–pays off.”