financed by the National Natural Science Foundation of China(No.31770419,31272331,30970375,30400047 to HW);the Postdoctoral Program of Agricultural Science and Technology Innovation Center in North-east China(No.150482 to WO)
Background:For secondary cavity-nesting bird species that do not add lining materials to nests,the presence of old nest material or organic remains that have accumulated within nest cavities from previous breeding eve...