The sugar-phosphate backbone of DNA is held together by covalent bonds.     The strands of DNA are joined by hydrogen bonds (H-bonds) between the nitrogenous bases o â¦ n either side. Adenine is joined to Thymine by 2 H-bonds. Cytosine is joined to Guanine by 3 H-bonds.
The mother will leave the nest and the newly hatched chicks sometimes for long periods of time to eat, drink or take a bathroom break. In some species the father will then take over nest duties, but in hummingbirds, itâs up to the mother to tend the eggs and the babies.
After they grow, she begins to give the chicks independence. 1  In about a week or so the growing chicks will be covered with fuzzy new feathers. 2  After about two weeks, they start to look more like small adult hummingbirds.  After three weeks, the young birds are ready to leave the nest forever.