Study finds selection for parental care in birds during the KT event

Yanornis figure, showcasing that like Enantiornithes and pterosaurs early members of the modern bird lineage flew soon after birth.

A recent study has found that, during the KT event, birds were subjected to selective pressures to be both small and develop parental care. This is consistent with previous studies finding Cretaceous enantiornitheans to have died out due to their supreprecocial habits, and the same likely also applying to pterosaurs and early members of Ornithuromorpha. All of these could fly since birth, and likely the fact that they needed to occupy different niches across their growth may have made them vulnerable to the demise of terrestrial ecosystems during the KT event.

The fact that parental care was selected for seems rather counterintuitive, since parents would have been forced to feed more mouths than the availiable food resources, but perhaps this helped young grow faster and with a more reliable source of food. Note that not all birds with parental care made it through either; hesperornitheans and ichthyornitheans both have growth rates suggesting rapid growth and thus parental care, but they died out.

Overall a fascinating study on the developmental ecology of prehistoric birds.