Hatching

Young #FoulshawOsprey chick number 1 hatched 37 days after the egg was laid. Numbers 2 and 3 just 36 days after their eggs were laid.

Ospreys can control the incubation period of their eggs and the adult female, Blue 35, was able to reduce the time between the first and last egg hatching helping to ensure that all chicks have a more even chance of survival.

Feeding

Newly hatched osprey chicks are somewhat helpless and for the first hour or two will wriggle in the nest recovering from the effort of pecking their way out of their shells. Within a very short time, their necks strengthen and they are able to hold their heads up. Then the feeding instinct kicks in and they furiously beg for food from the parent birds.

After 37 days of a fairly leisurely lifestyle, the behaviour of the parent ospreys changes as they adapt to the needs of their hungry youngsters. The Foulshaw male osprey, White YW, has increased his fishing trips and, as the sunny days lengthen, he has plenty of opportunity to provide more than enough food for the female and her brood.

The male brings the fish to the nest, normally having eaten the head first, and the female feeds herself and offers tiny pieces of fish to the chicks. When they first hatch, the chicks only take one or two beakfuls at feeding time before they're satisfied.

As the days go by, their need for food increases and the chicks become more demanding. Generally, the attentive female is able to make sure that all the chicks get as much food as they need, despite the persistence of the oldest chick to dominate mealtimes.

Imagine an egg, a large hen’s egg. The size and weight is about the same as a newly hatched osprey: around 50g. Within 6 or 7 weeks the young ospreys will have grown so fast that they weigh around 1.5 – 2 kg and have a wing span nearly as wide as we are tall. It's an incredible growth spurt in a very short time and is vital to enable the ospreys to tackle their challenging migration at the end of the summer.

Coping with this summer's heat

Unusually, these young ospreys have hardly experienced any rain so far this summer. Since they hatched, the weather has been exceptionally hot and dry. Instead of mum protecting them from the wet, she has shielded them from the sun providing as much shade as she can.

As with the adult ospreys, the youngsters pant to help keep themselves cool but, unlike the adults, they can’t go for a dip to cool off. It has been so hot that the chicks don’t need the warmth of Blue 35 to protect them.

On many occasions now she is staying a little way away from the nest, still keeping an eye on them in case of any unwelcome intruders.

As long as the chicks continue to be fed well, which White YW is doing admirably, they will get enough water from the fish they eat to keep them hydrated. These sunny, clear conditions are just perfect for YW’s fishing expeditions.

Feathers

When the ospreys hatch, they are covered in a soft white fluffy down except for the distinctive dark eye strip from the beak to the back of the head. This strip probably reduces the glare from the water when they are fishing.

Within ten to twelve days they grow a second down which is darker and more scaly; then, at two weeks, the pin feathers start to appear on the head and neck with body feathers following soon afterwards.

At three weeks, the youngsters are getting more mobile, shuffling around on their haunches before their wings start to develop. At four weeks they will be fully feathered and will soon be strong enough to stand up. By six weeks the wings are almost fully formed and their flying attempts are strong and controlled.

Fledging

Most ospreys fledge between seven and eight weeks with males tending to fledge a bit earlier than the females as they are smaller and lighter. Females tend to be 20% larger.

Once the ospreys fledge, they stay close to the nest site, gaining strength and developing their skills. When they are about twelve to fourteen weeks old they are strong enough to start their migration.

Before then though our brood at Foulshaw Moss has a busy time ahead: eating, growing, learning life skills and flying, not to mention keeping safe. Their next milestone will be in a few weeks’ time when they're ringed with identification tags on their legs, and maybe then we can find out which are male and which are female.

Follow their progress through our osprey live webcam here.

White YW is making very many fishing trips. Do you know how many he is doing each day?