Loons are large birds, with wing spans approaching four feet, but they are also relatively heavy birds so the large wings are essential. They are extremely efficient diving birds, and their legs are set well back on the body, which aids in propulsion in the water but makes navigating on land nearly impossible. A loon is vulnerable on land because it can only thrust its chest forward a few inches and drag the legs back underneath the body. Loons feed on fish and other aquatic life. They return to northern waters in the spring, where the longer days provide ample time for the biologically expensive activities of laying eggs and raising chicks.
Loons typically produce two eggs each year.
Incubation takes about 28 days, and the parents share the nest duty equally. The average loon pair in New Hampshire fledges one chick each year - heat stress during incubation and predation by large bass and raptorial birds shortly after a chick hatches take their toll. The adults now take on the substantial challenge of feeding the babies and themselves - diving for 30 to 50 seconds at a time, catching fish, and feeding them directly to the chicks. During the first week, a chick may crawl on to the back of a parent which is paddling along on the surface. The chicks grow very rapidly and are nearly the size of the adults within four to six weeks.