I was born in the days when babies were put outside in their prams to get the air, and my first memory - I must have been only a few months - is of lying on my back looking up into the rowan tree that grew in the middle of my granny’s back garden and hearing, or rather feeling, a gentle little rustling flutter in the branches above me.

I wasn’t old enough to wonder what it was but I have never, even now in my 80s, lost that memory and the feeling of mystery and excitement that it brought me, 

And then, later, a toddler stumbling through the park opposite my granny’s house trying to catch up with her and my mother, I remember stopping to watch a little bird hopping round in the grass. On my level. Making friends. I couldn’t talk to tell my mother what it was but she saw my eyes following it and I knew she and my granny were pleased too and that birds were one of the joys of life.

And then there were those childhood wanders and stoppings under the trees to the melodies of thrushes and blackbirds - I probably didn’t know the word “inspiration” but I think that’s what it was, perhaps too the start of my lifelong love of music. Then later brisk walks with my almost too know-all birding aunt: pointing out every little flutter or edge of a feather - a bit overwhelming, but it meant I got to feel the flap of a wing, the soar, the miraculous nests and colours.

I recall too walking through the woods with my classical-scholar father as we heard the constant voices of the pigeons and he told me that they coo in the “dochmiac” rhythm, the wildest most emotional most dramatic of all the ancient Greek meters - and they were: cooo cooo coo cooo, coocoocoo kooo coo cooo, those rhythmic stirring tones that I still hear every day from the trees opposite our house,

And in the autumn I look and listen for the double-wedged honk honk honk of the migrating wild geese.

How could I not be fascinated by birds and want to know more about them?

It was only much later as I grew to be myself a scholar that I discovered that birds were indeed the object of research and scientific investigation, giving a route not just to admire them but to learn about and - as humans always have - from these amazing creatures.

For years I’ve vaguely wanted to know more but it’s only now that I have thought that perhaps I should try to create a book to pass on some distillation of what I have learned and felt and loved about these wonderful parallel miracles of our earth.

So this, dear reader, dear birds of the sky and the trees, is it. Forgive its deficiencies, it is the best I can do.

What are birds?

You know birds, you see them every day. 

They hop visibly on our lawns, build nests in our hedges and trees, swoop over the sea, swim in ponds and rivers, fly amazing aerobatics in the sky, show us their incredible migrating navigating flocks. They sound their calls and songs through the woods, show off their colours, inform the symbolisms of our poetry. To an extent unequalled by any other untamed animals they are truly part of our everyday life,

But what are they, really? 

The answers surprised me, and may surprise you too. 

Let me start with the obvious things. Birds are a group of warm-blooded vertebrates within the earth’s animal kingdom, making up a class (in technical terminology, the aves)characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton adapted for flight.

They are everywhere, for, like grass, they live in all parts of the world, even the most inhospitable places.. 

They are incredibly varied too.  They range in size, for example, from the tiny 2.2 inch hummingbird to the 9 foot 2 inch ostrich,

and come in many shapes and forms, there are about ten thousand living species.

Birds have wings, that too is obvious These have developed from forelimbs and give birds the ability to fly through the air (there are a few exceptions as further evolution has led to the loss of flight in large birds such as ostriches, emus, rheas, cassowaries, and kiwis, also penguins, and some island species). Birds’ digestive and respiratory systems are uniquely adapted for flight. Several aquatic species, particularly seabirds and water fowl, have further evolved for swimming.

Compared to mammals?

There are several clear differences from mammals. Whereas birds have feathers, lack teeth and lay eggs, mammals have fur or hair for insulation, possess teeth and give birth to live young. 

But although birds are more closely related to reptiles than to mammals, birds and mammals do have characteristics in common. Both are warm-blooded, which means they can maintain a constant body temperature and do not need to rely on an external heat source to stay warm. This lends itself to several other commonalities, such as similar caloric requirements by weight and the ability to remain active in colder temperatures (cold-blooded animals, such as reptiles, do not have to eat as much, but they also cannot survive colder temperatures). Being warm-blooded gives birds and mammals the unique ability to live on any landmass on earth.

There are also some behavioural traits shared between birds and humans. Both tend to be more intelligent than reptiles, amphibians, or fish. Birds and humans form social groups with complex vocal inter-communication. Both usually care for their offspring for an extended period of time, as opposed to most other animals which don’t offer a high level of parental care (the length of time varies from species to species, depending on the age that the young are able to take care of themselves). Female mammals feed their young by lactating, while birds feed them beak to beak.

Birds and humans also share some traits that are due not to common ancestry but to “convergent evolution”, something that occurs when species that are not closely related evolve the same or similar traits due to similar evolutionary pressures.

Birds, then, are eventually reptiles - but at the same time with some physical and, as we have increasingly become aware in recent years, cultural overlapswith mammals.

How do birds behave? 

To summarise, typical bird behaviour includes cooperative living, nest building, and two-parent care of the young. Birds reproduce by laying sexually fertilised eggs, usually in a nest and incubated by the parents. With most birds there is an extended period of parental care after hatching.

Birds are essentially social and cultural beings and as such, like humans, learn and pass on knowledge from generation to generation. They are also social in the sense of communicating with each other through visual signals, calls, and songs, and of participating in such behaviour as cooperative breeding and hunting, flocking, and mobbing predators. Most species are socially (but not necessarily sexually) monogamous, usually for one breeding season at a time, sometimes for years or, as we shall see, for life.  

Many species of birds are economically important to us humans as food and as raw material for manufacturing. Both domesticated and undomesticated birds are good sources of eggs, meat, and feathers. Songbirds, parrots, and other species are popular as pets while guano (bird excrement) is harvested as a valuable fertiliser. In addition, birdwatching is important for study and leisure, and is now a significant part of the ecotourism industry.

In addition, for millennia and perhaps from the very ancientest of times, birds have had a prominent presence in human art, music, and literature.