Many species of birds build nests. These birds are born with the knowledge to engineer these stable structures that provide a safe and comfortable home for their offsprings. It's part of their instincts.
But just how were these instincts acquired?
One day, a bird must have built the first nest. How could this bird with very limited intelligence figure out all the steps to interweave all the twigs in the right order?
This bird couldn't go to bird engineering school, so he had to have the instruction manual coded in his DNA. How did it get there ? According to evolutionists, random mutations at reproduction caused the precise instructions to appear in the bird's DNA.
However, today we don't observe new knowledge entering the DNA trough mutations. Would you expect one day to witness a child born with the knowledge to build a house?
Creationists believe that birds were created with the instructions to build nests already programmed by God in their DNA. God knew that birds would need a nest and gave them the necessary knowledge from the very beginning.
It is logical to believe that amazing design in nature, like birds and their nests, require a designer.