Basin Notes - March 2011

Harbingers of Spring

Rain, gales, sunshine, frost and snow ... Yes, March can be relied on to give us very changeable weather. For some birds however the breeding season is well under way.

The largest of our corvid family, the raven, is usually our earliest nester. It is buzzard size and a strong, handsome bird with its all black plumage, shaggy throat feathers and stout bill. It nests mainly on crags and cliffs on the western side of Britain. Starting in mid-February an average of five eggs are laid and incubated by the female while the male bird carries food to her in his throat pouch.

In her eyrie on a remote mountain crag the golden eagle will start incubating her eggs this month. This will take around 45 days and while up to three eggs may be laid only one offspring is likely to be reared to adulthood.

The grey heron will makes its nest or refurbish an old one in early February in a heronry in the high treetops. Egg laying months are February, March and April and both parents are involved in incubation and they feed their chicks with regurgitated food. From hatching to fledging takes up to two months. The heron takes a wide variety of prey but its easy pickings at this time of year with so many frogs about.

The tawny owl is another early nester and the female will now be incubating her two to four round white eggs in a tree hole or in the nook of an old building. The owlets will leave the nest at around 28 days old and will be fed by their parents for a further three months before they are independent.

It is a busy time in the mammal world too. Many fox cubs are born this month and the vixen will rely on the dog to bring her food in the first week or two while she suckles her young. After two weeks the cubs will take regurgitated food and from 6 weeks onwards they will start exploring outside the den.

The brown hare of course goes a bit mad in March. Normally a wary animal, the springtime courtship is fuelled by "notching hormones". The buck is always ready to mate first, but the doe will fight him off, both standing on their hind legs and exchanging blows with their fore paws. The doe is larger than the buck and packs the bigger punch. The lady is always in control of the situation however and will mate only when she is good and ready. It's a harbinger of Spring ritual to remember and treasure.

Spring migrants from Africa will be arriving around the Basin during the last week of March and bird watchers will be looking for their first sighting of wheatear, sand martin, chiffchaff or os-prey. A first of the season was a red admiral butterfly flitting around the Visitor Centre on March 1st.