Tuesday, August 9, 2011
Swan and cygnets
I came across this Mute Swan (Cygnus olor) and her cygnets today, preening on a raised mound of land in the Charles River near a small heron rookery. It was difficult to make out how many cygnets were in the group, but I'd venture to say there were six. These cygnets are gray or "Royal" and start off with gray down and grow in gray-brown and white feathers, giving them a mottled look.
Male and female Mute Swans choose the nest site together and use any material within about 40 feet to make the nest. The female (or pen) lays between 1 to 12 eggs, the average being 6. The eggs are laid every other day and only when the last egg has been laid does incubation start. The incubation period lasts about 35 days and the pen only comes off the nest for very short periods to drink and stretch her legs. The male (or cob) takes over after a recognition head lifting ceremony. The cob will defend the nest against foxes, dogs and other predators.
Cygnets normally take to the water 24 hours after the last cygnet has hatched, usually in May. The parents do not feed them, but the pen will 'foot paddle' to bring food to the surface for cygnets to eat and pull out reeds which the young would otherwise be unable to reach. One parent will always be on guard and they often travel in line with one parent at the back, the other in front. The pen will carry the young on her back. The swan family is very close and if a cygnet is lost, the parents will often look for it up to a week. Natural predators are pike, foxes, mink and cold, wet weather. Unfortunately man poses further hazards.
Nature has been clever with the swan's moulting period when they cannot fly. The moult takes about 6 weeks and for non-breeding birds takes place about July time. A pair with cygnets moult at different times, first the pen and then the cob in August to September so that one of them can always defend the young.
Source: Fairford Swan Aid
Swan lovers everywhere will be interested in The Swan Sanctuary and Simply Superb Swans.