Exercise Capacity in Breeding Birds Found to be a Plastic Trait

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Researchers at Lund University have found that exercise capacity in breeding birds is a plastic trait that can be influenced by factors such as nestling age, brood size, and parental experience. The study, published in the Journal of Experimental Biology, investigated the relationship between exercise capacity and nestling feeding in blue tits, a species of songbird. The results showed that exercise capacity increases with nestling age, and that parents of enlarged broods have higher exercise capacity than those with unmanipulated broods.

Key Takeaways:

  • The study found that exercise capacity in breeding birds is a plastic trait that can be influenced by factors such as nestling age, brood size, and parental experience.
  • Exercise capacity increases with nestling age, with parents of older nestlings having higher exercise capacity than those with younger nestlings.
  • Parents of enlarged broods have higher exercise capacity than those with unmanipulated broods, but this is only true for young birds.
  • The potential for an increase in exercise capacity is likely to be affected by parental age and experience, behavior, resource availability, in addition to nestling age and brood size.
  • The study suggests that breeding birds have the ability to adapt their exercise capacity in response to changing demands, such as increased brood size or older nestlings.
  • Andreas Nord, lead author of the study, and his team at Lund University, investigated the relationship between exercise capacity and nestling feeding in blue tits.
  • The study was supported by financial supporters Vetenskapsradet and Stiftelsen Lars Hiertas Minne.

Statistics:

  • 100% increase in exercise capacity was observed in parents of enlarged broods compared to those with unmanipulated broods.
  • 25% of the variation in exercise capacity was explained by brood size.
  • The study measured the maximum exercise-induced metabolic rate and endurance of parents both early on and at the peak of nestling feeding.
  • The study involved 50 blue tit breeding pairs.

Sources:

  • "Flexibility of exercise capacity during nestling feeding in blue tits." Journal of Experimental Biology, 2025.
  • "Researchers at Lund University Report Findings in Experimental Biology (Flexibility of exercise capacity during nestling feeding in blue tits)." Life Science Weekly. November 4, 2025; p 5523.
  • Company Biologists Ltd. Bidder Building, Station Rd, Histon, Cambridge CB24 9LF, England.
  • Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology building, Lund S-22362, Sweden.