BBC: Secret Life of Birds

'A bird's life in Wales must be wonderful.

'A life made in heaven.

'Anything but.

'Birds have to work from dawn to dusk to find food and water.

'If they don't, they die.

'They have to battle with the elements too.

'Survival, especially during winter, is always difficult.

'And during the spring, they're busy raising families.

'They also have to put up with us

'and find a way of surviving in our artificial landscape.'

In this series, I'll be finding out what a bird's life is really like in Wales.

I'm going to be discovering the vast array of species we have here.

And I'm going to be probing into their secret lives.

'Llandegfedd Reservoir near Pontypool in South Wales.

'It's late March.

'A male great crested grebe is courting a female.

'It's difficult to tell the male and female apart. They look the same.

'But the male is the one offering nesting material to the female.'

Everybody's got their own favourite signs of spring,

whether it's the first primrose or the first swallow,

but for me, it's watching great crested grebes in their courtship dance.

There's a pair in front of me here

and they've set up territory in this shallow little inlet.

At the moment, they're indulging in a bit of head shaking.

They have been parallel swimming.

And this, more than anything else,

tells me that the long, hard winter we've just experienced

has now come to an end, and spring has finally arrived.

'Great crested grebes have the most complex courtship display

'of any Welsh bird.

'The grebes approach each other and dance.

'The elaborate ear tufts only grow during spring.

'The rest of the year, they disappear.

'The headdress is clearly an important part of the display.

'Birds court in a variety of ways.

'These are mute swans.

'They, too, dance.

'Black-headed gulls drop their wings in their display.

'Sandwich terns court by sharing food.

'But in terms of survival and raising a family,

'the ability to provide food is essential.

'On the uplands of Mynydd Hiraethog in Clwyd,

'another bird uses food in its courtship.

'This is a male hen harrier.

'And this is a female.

'They look completely different.

'The male is blue-grey.

'The female is brown and a much bigger bird.

'The difference in size means that they can exploit

'a wide variety of food on upland moors.

'They can hunt different prey.'

A male hen harrier has just come in with food,

probably a meadow pipit or a vole.

She'll sit in the tall heather down there, just waiting for him,

because he'll be the one who hunts.

He'll bring food for her and when he gets above her,

he whistles this low kind of whistle.

Up she then comes.

He'll hold the food underneath him, she flips under him,

he then drops it last minute, she takes that food

and goes off to feed, in what's called the food pass.

When you watch it like this, in an area like this, it's stunning.

It's absolutely fantastic.

'On the east side of Anglesey

'lies the beautiful quiet bay of Fedw Fawr.

'Rock pipits are found here,

'as they are all along the rocky coasts of Wales.

'This is a male.

'He's claimed a thin band of cliffs as his territory.'

If you're going to live here, if you're going to establish a territory here,

if you're going to mate here,

you need to be able to communicate in a particular way.

Rock pipits haven't got a good song. They're not colourful birds.

So what they do is they display

and they display by going up into the air.

'All pipits do this.

'They fly high up in the air, call, and just drop.

'They'll perform this parachute ritual over and over again.

'And they'll continue to display, even when the female has been found.

'The territory and the female must be kept.

'Having courted successfully,

'the business of raising young can commence.

'And it's not always a romantic affair.

'And of course, there's also a nest to be built.

'I've come to a small patch of woodland near Newtown in Powys

'and Wales' finest nest builder has built a home.'

This is a typical long-tailed tit's nest.

It's tucked out of the way in a real jungle of thorns and bramble bushes.

They're incredible things when you consider that every single nest

has got at least 1,000 feathers in it.

Some have even got 2,000 feathers.

The difference depends on where the nest is.

If it's in a fairly open, exposed area, it'll have more feathers.

If, like this one, it's in a nice, sheltered, warm spot,

it'll have fewer feathers.

When the female lays her eggs,

there's enough space in there for everyone.

But when those eggs hatch and the chicks are about two weeks old,

like they are in this nest, there's hardly any room at all.

So what they do is they weave spiders webs into the nest,

and as the chicks grow, the nest expands out.

It's a remarkable feat of engineering really.

'The building abilities of birds are quite remarkable.

'They're well accomplished nest builders,

'and they can build a nest very quickly.

'These are rooks and they're building nests

'in the centre of Newtown in Powys.

'They nest early in the year, usually during late February.

'And different birds have different techniques.

'Some do it the hard way.

'They break off twigs to build a nest.

'Others do it the easy way.

'They steal twigs from other rooks' nests.

'This gold finch is building a nest at the end of a branch.'

When I see birds building a nest,

it always strikes me that they've got a small brain and a beak.

I've got two hands and a large brain

and yet I couldn't do in 12 months what they do in just a few days.

'This nuthatch is building a very different kind of nest

'in Coed Crafnant Wood near Harlech.

'It has commandeered an old woodpecker's nest.

'A hole in a tree which has been dug out by a woodpecker.

'But the entrance hole is too big for the birds,

'so it reduces the size by filling it with mud.

'It takes the nuthatch pair two days to achieve the desired size.'

And there it is. They've finished all the building work now.

Isn't that amazing? They take a hole that's a little bit too big

and make it the perfect size by packing it down with wet mud.

That mud is still a little bit damp up there.

They'll be leaving that now for a week, maybe two weeks,

for that to dry out. And it's like concrete, it's so hard.

She'll be lining the nest inside with bits of bark, oddly enough.

And when that's all done,

it's only then that she thinks about laying her eggs.

'Not all birds nest in trees.

'Over time, birds have adapted to the habitat that suits them best.

'We're in the Grwyne Valley near Abergavenny.

'And this is a dipper.

'A bird that lives along rivers.

'It's collecting food for its chicks.

'And it's built a nest on the riverbank.'

This nest blends in so well. It's just on the bank here now.

The bird itself is dependent on the river,

completely dependent on the river, because that's where the food is.

And so is the nest, really.

You always find it out over water like this.

The reason for that is because the droppings fall in the river

and get washed away.

'The dipper is our only small bird

'that swims underwater to look for food.

'It collects insect larvae from the riverbed.

'The chicks are fed by both parents.