Why Carolina Wrens Choose to Hatch More Boys or Girls

Ever wondered why some bird moms have more boys or girls? It all comes down to their quality and the environment. Carolina wrens, which are loyal to one mate, face this dilemma. If a mom is in good shape, she might have bigger sons who can fight for food. But if she's really high-quality, she might have more daughters instead. This is because daughters can provide better care for their kids in the future. Researchers swapped chicks between nests to figure this out. They found that sons grew larger than daughters, and dads who brought lots of food had a big impact on their sons' chances. Moms who were in great condition and had food-bringing dads often had more boys. But, interestingly, daughters from these high-quality moms grew up to have big families themselves. So, it's like these moms are strategizing based on their future grandkids!