Migratory birds can adjust to climate change, study finds
Helping birds fly north earlier improved breeding success.
A study has suggested that teaching birds to migrate further north earlier might improve their breeding chances.
The research was proposed in response to the effects of climate change on migratory birds’ breeding success. The earlier arrival of spring in Sweden has been affecting birds’ abilities to feed properly.
This is because the warmer weather is causing caterpillars to hatch, grow and pupate earlier than in previous years. Migratory birds that cannot eat caterpillars that have reached the pupal stage are therefore running out of food far sooner, resulting in many chicks starving.
This has prompted researchers from Lund University, Sweden, to test a theory that encouraging these migratory birds to travel and breed earlier could improve breeding success.
The biologists caught pied flycatchers that had arrived in the Netherlands prior to breeding and drove them through the night to Vombs Fure, an area of pine forest outside Lund in Skåne, where they were released.
The caterpillar availability in Skåne peaks two weeks later than in the Netherlands, a distance of 600km that the pied flycatcher would cover in two nights.
Researchers observed that the birds synchronised well with the new food peak, and began to breed ten days earlier. They also saw improved breeding success in these birds than birds elsewhere in Sweden and the Netherlands.
The success of the project continued following these chicks’ first spring migration. Rather than stopping in Netherlands they returned to the forest where they were born, arriving before the Swedish pied flycatchers.
This meant that the chicks then born to these pied flycatchers were also better fed.
The success of this project suggests that encouraging migratory birds to naturally migrate further and earlier could have long term benefits for the breeding success of the species.
Jan-Åke Nilsson, study author and biology researcher at Lund University, said: “The number of small birds, particularly migratory birds, has decreased drastically throughout Europe.
“By flying a little further north, these birds, at least in principle, could synchronise with their food resources and there is hope that robust populations of small birds can be maintained, even though springs are arriving ever earlier.”
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