Over the past couple of months we’ve have been enjoying brilliant song and dazzling displays from our birds. But they’ve now moved on to the serious business of raising a family, and we are welcoming new arrivals. Eggs will have hatched and young birds will be making demands of their busy and harried parents!
We’ve had reports of nightingales, lesser whitethroat, garden warbler and blackcaps feeding young around the hedgerows and in the scrub.
Juvenile blackcap. Photo by Graham Osborne
As I took a walk in Black Wood this week it was busy with families of blue, great and coal tits scouring the oaks for food. I particularly enjoy watching the interactions between parents and youngsters and puzzling over the occasional tricky-to-identify juvenile! It's always great to hear what you have seen around the nature reserve, so do report your sightings to the team at our welcome hut.
There are two different biological strategies for the development of birds; some are precocial where the eggs are incubated for a longer time, and on hatching the chicks are mobile within hours, have some downy feathers to keep them warm and can find food for themselves (with a little help). Others are altricial where the eggs hatch pretty quickly (within a couple of weeks) but the young are helpless, naked and blind and will need to be fed and incubated until they fledge. Let’s meet some of each…
Out on the wetlands at Pulborough Brooks our lapwings incubate their eggs for almost a month. When the chicks hatch, they are adorable bundles of down, who must quickly get used to their long spindly legs and within hours be ready to scurry into the cover of a tussock of grass. Lapwings nest on the ground, in a simple scrape in the mud, so the youngsters are vulnerable to predators and must be able to run and hide from an early age. They feed themselves soon after hatching, although they are still cared for by both parents until they can fly.
Lapwing brood. Photo by Graham Osborne.
In a hole in a tree is an unexpected nest; a mandarin duck who has laid her clutch of eggs 10 metres up in a cup of downy feathers. The ducklings hatch and, like the more familiar mallard ducklings, are born with a downy coat. Although they cannot fly, they need to leave the nest quickly to feed in the water. Eek…it’s a long way down! The female flies to the ground and attempts to coax her ducklings out of the nest hole and to jump to the ground. Once they have made it to the ground she leads them to water to feed. Both adults will then protect the ducklings as they feed and develop feathers, ready to fly after about 40 days.
Meanwhile, in an incredible egg-shaped nest constructed of lichen, moss and spider’s silk, the long-tailed tit’s 10 eggs have hatched after just two weeks. The young will be featherless and unable to feed themselves, so the parents must use all of their energy to feed those hungry mouths and keep the chicks warm. For the next two weeks, the parents have to work incredibly hard but the chicks develop quickly, their elasticated nest expanding with them. After 14 – 18 days the chicks fledge but they all stay together as a family for another 2 weeks. This is one of my favourite things to see and they are surprisingly easy to find as they are very vocal, chatting to one another in high pitched squeaks and seeps.
In a purpose-built nestbox on the trunk of an oak, busy blue tits are constantly toing and froing with mouthfuls of caterpillars. All 12 of their eggs have hatched, and whilst the chicks may be small and helpless they can certainly be demanding. Each chick can eat around 100 caterpillars a day, so the parents must find 1200!
This juvenile blue tit looks rather grumpy - perhaps the caterpillars are in short supply! Photo by Graham Osborne
They’ll continue to do this, interspersed with keeping the nest clean by removing faecal sacs and occasionally brooding the chicks to keep them warm. Thankfully, the chicks leave the nest after 2 – 3 weeks. The adults breath a sign of relief and decide not to try again for another year.