The great tit and other birds can adapt to changes in their food supply as a result of climate change, but they run into trouble if the changes happen too quickly.
An ever warmer climate could be bad news for species that depend on stable and abundant access to food at certain times of the year.
“If changes happen too fast, species can become extinct,” says Emily Simmonds, an associate professor at NTNU’s Department of Biology.
She is the first author of an article in Ecology Letters that addresses how great tits can be affected if the supply of larvae changes in the spring.
Spring, plants and larvae arriving earlier
Several bird species depend on the abundance of larvae while their young are small. If the larvae supply peaks earlier in the spring than normal, there may simply be too little food for the hatchlings.
A warming climate can bring about changes like this. An earlier spring causes trees to leaf out earlier, which in turn causes the larvae that feed on the plants to hatch out earlier.
“When the climate changes, the interactions between different species changes too,” Simmonds says.
She and a team of researchers at the University of Oxford used population models to calculate the consequences of different climate scenarios. They wanted to see at what point the changes would happen too fast for the great tit to modify its behaviour quickly enough to keep up with the larvae.